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1
Bellingeri, Arianna. "Ecotoxicity and sub-lethal effects of accidentally dispersed and purposely produced nanoparticles through a multi-trophic approach." Doctoral thesis, Università di Siena, 2022. http://hdl.handle.net/11365/1201982.
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The use of nanotechnology in everyday life received a boost in the last twenty years thanks to improved
performances and adjustable properties of engineered nanomaterials (ENMs) and nanoparticles (NPs)
compared to traditional materials. ENMs and NPs are purposely produced for a wide variety of
applications and, as recently discovered, are also accidentally formed during some industrial processes.
Being so extensively employed they end up into the natural environment and their occurrence,
especially in the aquatic environment, has been recently confirmed, although only for selected NPs.
In fact, due to technical limitations in the detection of NPs in natural matrices, the actual concentrations
are mostly established based on predicted environmental concentrations (PECs), in the range of ng-mg
L-1. The consequences of environmental exposure for aquatic organisms, especially in the long-term,
are not well-understood and, due to the large variety of features contributing to NP diversity, common
guidelines for NP risk assessment are in their infancy. The aim of this thesis was to investigate the
effects of two different type of NPs, polystyrene nanoparticles (PS NPs) as proxy for nanoplastics and
silver nanoparticles (AgNPs), toward aquatic microorganisms at different levels of ecological
organization. Selected organisms belonging to the bacterial, microalgal, and microcrustacean
communities, from the freshwater and the marine environment, have been investigated. Both NPs
were thoroughly characterized for their properties and their behaviour in exposure media by means of
dynamic light scattering (DLS), transmission electron microscopy (TEM) and, in the case of AgNP,
inductively coupled plasma mass spectrometry (ICP-MS) for the assessment of ion release. When
possible, all the elements possibly interfering with the observed effects were determined and reported,
in order to help in the correct assessment of NP mode of action in terms of ecotoxicity. AgNP synthesis
process was reported in detail, while additives in PS NP suspension were listed and their final
concentration in exposure media was calculated. Moreover, for a more correct interpretation of NP
behaviour data, the composition of all exposure media and their physico-chemical parameters were
reported and considered in data analysis. All biological models were tested for acute toxicity and, when
allowed by the organism ecology, chronic toxicity was assessed as well. Particular attention was given
to sub-lethal effects occurring upon exposure to NPs and how these could be linked to more
detrimental effects in the long-term and furthermore having implications at the ecological level. Results
enriched the data pool on NP ecotoxicity at various levels of aquatic food chains, while also highlighting
the importance of long-term exposure and sub-lethal effects. Marine diatom exposed to PS NPs showed
no effect on growth but resulted in PS NP adhesion to the algal surface and reduced chain length of
algal cells, with possible implications for algal buoyancy and bloom formation. The first evaluation of
novel AgNPs designed for water remediation successfully resulted in low dissolution and no toxicity for
two freshwater and marine microalgae. A more thorough investigation, however, showed effects in the
long-term especially for marine microcrustaceans and suggested a toxicity linked to the AgNP nano-size
rather than to dissolved Ag values. Effect comparison of two differently coated AgNP to bacteria and
microalgae revealed a different mode of action based on coatings: one confirmed to be influenced by
the nano-size while for the other a dissolution-based toxicity was observed. Overall results showed that
the consequences of NP exposure more likely originate from the physical interaction with the organism
membrane/cell wall or body surface in long-term exposure scenarios, and with, often, unexpected
outcomes compared to traditional toxicity endpoints (i.e., cell growth and mortality). New
ecotoxicological outcomes should be considered in order to provide a more realistic assessment of the
risk associated to NP use and discharge in the aquatic environment, while a more ecologically-based
design for new generations of ENMs should be promoted.
2
Fonner, Adam M. "An Investigation on Syndiotactic Polystyrene Aerogel Coating of Macroporous Fabric via Dip Coating Method." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron15550203400871.
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Zhou, Bo. "The preparation and characterization of thermo-sensitive colored hydrogel film and surfactant-free porous polystyrene three-dimensional network." Thesis, University of North Texas, 2001. https://digital.library.unt.edu/ark:/67531/metadc3019/.
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Polymer hydrogel films change their properties in response to environmental change. This remarkable phenomenon results in many potential applications of polymer hydrogel films. In this thesis colored thermo-sensitive poly(N-isopropylacrylamide) (PNIPAAm) hydrogel film was prepared by firstly synthesizing polymer latex and secondarily crosslinking the nanoparticles and casting the polymers onto glass. The shape-memory effect has been observed when changing the environmental temperature. The temperature-dependent of turbidity of polymer hydrogel film was measured by HP UVVisible spectrophotometer. This intelligent hydrogel might be used in chemomechanical systems and separation devices as well as sensors. Polymer adsorption plays an important role in many products and processes. In this thesis, surfactant-free three-dimensional polystyrene (PS) nanoparticle network has been prepared. The infrared spectroscopy and solubility experiment are performed to prove the crosslinking mechanism, also the BET method was used to measure the adsorption and desorption of polystyrene network. The BET constant (C) is calculated (C=6.32). The chemically bonded polymer nanoparticle network might have potential applications as catalyst or used for chromatographic columns.
4
Heed, Elias. "Investigation of the effects of nanoparticle size on blood activation using a human wholeblood model." Thesis, Uppsala universitet, Klinisk immunologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-265904.
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Nanoparticles are used more and more extensively in today's society, especially in the industry sector. Humans get exposed to nanoparticles daily but the effect is a topic that has not been fully explored yet and its effect on humans is still unknown.The purpose of this project was to investigate whether the size of nanoparticles is a factor that influences their effect on humans, mainly the effect on blood activation. In order to study this, nanopaticles of polystyrene with three different sizes (75, 120 and 260 nm) were selected and incubated in a human whole blood model, the Chandler loop. The samples from the Chandler loop experiments were analysed with three different ELISA's: C3a, terminal complement complex (TCC, sC5b-9) and thrombin-antithrombincomplexes (TAT).The results in this study indicate that the smallest nanoparticle has a higher potential for activating the coagulation system than the larger ones. The complement system did not seem to be significantly activated from the nanoparticles. More experiments needs to be done in order to get a better statistic value but just as it is the results look promising and there is a tendency for a higher activation of the coagulation system with the 75 nm nanoparticles.
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Prime, Dominic Charles. "Switching mechanisms, electrical characterisation and fabrication of nanoparticle based non-volatile polymer memory devices." Thesis, De Montfort University, 2010. http://hdl.handle.net/2086/3314.
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Polymer and organic electronic memory devices offer the potential for cheap, simple memories that could compete across the whole spectrum of digital memories, from low cost, low performance applications, up to universal memories capable of replacing all current market leading technologies, such as hard disc drives, random access memories and Flash memories. Polymer memory devices (PMDs) are simple, two terminal metal-insulator-metal (MIM) bistable devices that can exist in two distinct conductivity states, with each state being induced by applying different voltages across the device terminals. Currently there are many unknowns and much ambiguity concerning the working mechanisms behind many of these PMDs, which is impeding their development. This research explores some of these many unanswered questions and presents new experimental data concerning their operation. One prevalent theory for the conductivity change is based on charging and charge trapping of nanoparticles and other species contained in the PMD. The work in this research experimentally shows that gold nanoparticle charging is possible in these devices and in certain cases offers an explanation of the working mechanism. However, experimental evidence presented in this research, shows that in many reported devices the switching mechanism is more likely to be related to electrode effects, or a breakdown mechanism in the polymer layer. Gold nanoparticle charging via electrostatic force microscopy (EFM) was demonstrated, using a novel device structure involving depositing gold nanoparticles between lateral electrodes. This allowed the gold nanoparticles themselves to be imaged, rather than the nanoparticle loaded insulating films, which have previously been investigated. This method offers the advantages of being able to see the charging effects of nanoparticles without any influence from the insulating matrix and also allows charging voltages to be applied via the electrodes, permitting EFM images to capture the charging information in near real-time. Device characteristics of gold nanoparticle based PMDs are presented, and assessed for use under different scenarios. Configurations of memory devices based on metal-insulator-semiconductor (MIS) structures have also been demonstrated. Simple interface circuitry is presented which is capable of performing read, write and erase functions to multiple memory cells on a substrate. Electrical properties of polystyrene thin films in the nanometre thickness range are reported for the first time, with insulator trapped charges found to be present in comparable levels to those in silicon dioxide insulating films. The dielectric breakdown strength of the films was found to be significantly higher than bulk material testing would suggest, with a maximum dielectric strength of 4.7 MV•cm-1 found, compared with the manufacturers bulk value of 0.2 – 0.8 MV•cm-1. Conduction mechanisms in polystyrene were investigated with the dominant conduction mechanism found to be Schottky emission.
6
Cellier, Julien. "Etude et caractérisations de membranes nanocomposites hybrides pour pile à combustible du type PEMFC." Thesis, Tours, 2017. http://www.theses.fr/2017TOUR4001/document.
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La membrane conductrice protonique constitue un rouage essentiel du fonctionnement des piles à combustible PEMFC. Les travaux de recherche présentés dans ce document consistent à développer une membrane non perfluorée basée sur une technologie nanocomposite hybride susceptible d’être produite à faible coût. Cette membrane est composée d’une matrice poly(VDF-co-HFP) dans laquelle sont dispersées des nanoparticules de silice fonctionnalisée par de l’acide poly(styrène sulfonique) (PSSA). Ce travail a porté sur l’étude de la mise en oeuvre de la membrane afin d’obtenir une membrane homogène et dense avec des caractéristiques physico-chimiques et électrochimiques intéressantes. Les performances en pile après rodage à 60 °C sont extrêmement satisfaisantes avec un gain en densité de puissance de 40 % à 0,7 V par rapport au Nafion® NRE211. Les études de durabilité de la membrane ont mis en évidence un phénomène d’élution de la silice fonctionnalisée ayant pour conséquence un fort déclin de tension. Différentes stratégies de modification de la membrane ont été proposées pour améliorer la stabilité de la membrane. Les plus intéressantes consistent à modifier la morphologie de la matrice (grades de PVDF plus rigides ou réticulation du poly(VDF-co-HFP) par irradiation) pour mieux confiner les charges ou à greffer la silice fonctionnalisée sur la matrice. Cette dernière stratégie conduit à une diminution par trois du gonflement et par 2,5 de la vitesse de déclin à 80°CThe proton conductive membrane is an essential part of the operation of PEMFC. This document presents the development of a non-perfluorinated membrane based on a hybrid nanocomposite technology likely to be produced at low cost. This membrane is composed of a poly(VDF-co-HFP) matrix in which are dispersed poly(styrene sulphonic acid) (PSSA) functionalized silica nanoparticles. This work focuses on the study of the implementation of the membrane to obtain a homogeneous and dense membrane with good physicochemical and electrochemical characteristics. Fuel cell performances after running at 60 °C are extremely satisfactory with a gain, compared to Nafion NRE211, of 40% for the power density at 0.7 V. However, the durability studies showed an elution phenomenon of the functionalized silica particles which results in a high voltage decline. Different membrane modification strategies have been proposed to improve the stability of the membrane. The most interesting involve modifying the morphology of the matrix (more rigid grades of PVDF or poly(VDF-co-HFP) crosslinking by radiation) to better confine the particles or grafting functionalized silica to the matrix. This last strategy leads to a threefold decrease of the swelling and 2.5 factor of the decay rate at 80 °C
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Horgan, Adrian. "Polystyrene nanoparticles based on block and graft copolymers." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343355.
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Al, Khafaji Ammar Sahib Abdulameer. "Understanding the uptake of polystyrene nanoparticles by the nasal mucosa." Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/2176.
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Nanoparticles have many proposed advantages for use in nasal drug delivery systems. Nanoparticles can improve uptake and efficacy and lower toxicity compared to the drug alone. In order to study the transport behavior of nanoparticles across nasal tissues, the uptake of non-biodegradable, fluorescently-labeled, carboxylate-modified polystyrene nanoparticles was measured. These 40 nm particles are spherical in shape and loaded with fluorescein, a fluorescent dye that can be measured spectrophotometrically, to determine the number of particles that entered the nasal tissues. In order to identify the pathways involved in the uptake of these particles, different pharmacologic inhibitors were also included in the nanoparticle transport studies. The results indicate that the nanoparticles enter the nasal tissues using several endocytosis mechanisms, namely, macropinocytosis, clathrin-mediated endocytosis, and caveolin-mediated endocytosis. These findings suggest that more than one endocytic pathway is involved in the uptake process in the nasal tissues, and these multiple pathways may help to increase the total nanoparticle uptake in the nasal tissues.
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Shen, Jiong. "Application of nanoparticles in polymeric foams." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1150139899.
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Li, Weiya. "Assemblage induit en milieu solvant de nanoparticules de silice à patchs : vers de nouvelles molécules colloïdales." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0127.
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Cette étude porte sur l’assemblage de particules à patchs pour obtenir de nouveaux matériaux. L’étatde l’art a permis de choisir et de mettre en oeuvre une stratégie originale dont la force motrice est l’assemblageinduit en milieu solvant, c’est-à-dire basé sur le caractère collant des macromolécules de polystyrène (PS)lorsqu’elles sont soumises à un mélange d’un bon et d’un mauvais solvant. Nous avons étudié l’assemblage enclusters, en chaînes ou en monocouches de nanoparticules (NPs) de silice possédant respectivement un, deux outrois patchs, constitués de macromolécules de PS greffées à des endroits spécifiques de leur surface. Les NPs desilice à un patch, présentant un rapport de taille patch/particule contrôlable, ont été synthétisées avec succès parune étape de séparation de phases induit par gonflement suivie d’un dépôt de silice régiosélectif. Leur assemblagea été réalisé dans des mélanges binaires DMF/éthanol. Les effets de la qualité du solvant, de la force decentrifugation, de la concentration en NPs, de la durée d'incubation et du rapport de taille patch/particule ont étéétudiés et discutés. La stratégie a été étendue pour obtenir des clusters à base d’or. Les NPs de silice à deuxpatchs ont été préparées par un procédé de polymérisation en émulsion ensemencée du styrène et le rapport detaille patch/particule a été ajusté via le taux de recroissance du noyau de silice. L’assemblage en chaînes des NPsa été réalisé dans des mélanges THF/solution aqueuse de NaCl en faisant varier la concentration en NaCl, lerapport volumique THF/eau, la durée d’incubation, la concentration en NPs et le rapport de tailles patch/particule.Nous avons montré que la cinétique de croissance des chaînes est typique d’une croissance par étapes. Desstratégies pour imiter des homopolymères, des copolymères statistiques, des copolymères séquencés à blocs etdes polymères ramifiés ont été mises en oeuvre, en utilisant comme briques de base des NPs à un patch, des NPsà deux patchs avec des tailles ou des fonctions de surface différentes et/ou des NPs à trois patchs. Les NPs desilice à trois patchs ont été obtenues par la même voie de synthèse que celles à deux patchs. Pour les assemblerdans des structures 2-D en nid d'abeille, nous avons utilisé la technique de Langmuir et nous avons étudiél'influence de différents paramètres expérimentaux. Une étape de recuit sous vapeur de THF a été mise en oeuvre,ce qui a permis de renforcer mécaniquement l’assemblage, mais sans effet significatif sur la compacitéThis study deals with the assembly of patchy particles to get new materials. The state-of-the-art allowedus to select and implement an original strategy whose driving force is the solvent-induced assembly, i.e. based onthe stickiness of polystyrene (PS) macromolecules when they are subjected to a mixture of good and bad solvents.We investigated the assembly into clusters, chains or monolayers of one-patch, two-patch or three-patch silicananoparticles (NPs), respectively, the patches being PS macromolecules grafted at specific positions on theirsurface. One-patch silica NPs with controllable patch-to-particle size ratio were successfully synthesised throughphase separation and site-specific silica coating. Their assembly was performed in DMF/ethanol binary mixtures.The effect of the solvent quality, centrifugation force, particle concentration, incubation time and patch-to-size ratiowas investigated and discussed. The strategy was spread to obtain gold-coated clusters. The two-patch silica NPswere prepared through a seed-growth emulsion polymerisation of styrene and the patch-to-particle size ratio wasadjusted through the extent of the silica core regrowth. The chaining of the NPs was efficiently achieved in theTHF/NaCl aqueous solution mixtures by varying the NaCl concentration, solvent quality, incubation time, NPsconcentration and patch-to-particle size ratio. We showed that the kinetics of the chaining process is characteristicof a reaction-controlled step-growth polymerisation. Strategies to mimic homopolymers, random copolymers, blockcopolymers and branched polymers were implemented by using one-patch NPs, two-patch NPs with different sizes/surface chemical functions and/or three-patch NPs as building units. The three-patch silica NPs were obtainedthrough the same synthetic pathway than two-patch ones. For assembling them in honeycomb-like 2-D structures,we used the Langmuir technique.and we studied the influence of different experimental parameters. THF vapourannealing was implemented to reinforce mechanically the assembly but without significative effect on the packingdensity
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Yammine, Elham. "Synthèse de nanoparticules de latex de polystyrène à patchs magnétiques." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0397.
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Les particules à patchs magnétiques ont pris une importance toute particulière dans l’étude des assemblages vers de nouvelles structures colloïdales. L’état de l’art nous a montré que la majorité des systèmes synthétisés et étudiés concerne des particules à un seul patch magnétique limitant ainsi les possibilités de structures accessibles par assemblage. Notre objectif s’est donc centré sur l’obtention de nanoparticules sphériques de polystyrène (PS) porteuses de plusieurs nanoparticules superparamagnétiques à leur périphérie. La voie multi-étapes retenue a consisté à préparer par polymérisation en émulsion ensemencée des particules Janus magnétiques (MJPs) présentant un nodule de PS qui a ensuite été rendu « collant » dans un mélange de bon/mauvais solvant pour fusionner avec celui d’un nombre limité de particules similaires. Pour servir de patchs magnétiques d’environ 100 nm, nous avons préparé des supraparticules colloïdales de nanoparticules d’oxyde de fer superparamagnétiques par un procédé incluant des étapes d’évaporation d’une phase émulsifiée, de consolidation par la silice et de resserrement de la distribution de taille par purification. Les paramètres optimaux de la polymérisation en émulsion ensemencée (composition du mélange de tensioactifs, nature et taux de greffage de l’agent de couplage) et de l’assemblage (nature et fraction du bon solvant, concentration particulaire, température et durée d’incubation) ont été préalablement déterminés avec des nanoparticules-modèles de silice présentant un diamètre et un état de surface similaires. L’application de ces conditions aux MJPs s’est avérée plus compliquée que prévue notamment en raison de la faible quantité de supraparticules disponible et cela a notamment conduit à définir de nouvelles conditions de polymérisation en émulsion ensemencée. Finalement, des lots de nanoparticules de latex à deux ou trois patchs magnétiques ont été obtenus, mais nécessiteront des étapes de purification avant d’envisager des études d’assemblage sous champ magnétiqueMagnetic patchy particles are of great interest for assembly into novel colloidal structures. The state of the art showed us that the vast majority of synthesized and studied systems concerns particles with a single magnetic patch, thus limiting the structures accessible by particles assembly. Therefore, the main goal of the present study was to develop spherical polystyrene (PS) nanoparticles with two or many superparamagnetic nanoparticles on their surface. Our multistep process involved first the fabrication of Magnetic Janus particles (MJPs) by seeded-growth emulsion polymerization and subsequent incubation in suitable mixtures of good and bad solvents to make their polystyrene lobe “sticky”. MJPs are then ready to coalesce into self-assembled structures with small aggregation numbers. In order to obtain magnetic patches with a size range of 100 nm, we prepared colloidal supraparticles highly loaded with superparamagnetic iron oxide nanoparticles through a multistep procedure, including evaporation-induced emulsion, silica coating and purification, leading to a narrowing of the size distribution. The optimal parameters of the seeded-growth emulsion polymerization (surfactant mixture composition, coupling agent type, surface grafting density) and of the assembly (solvent quality, good solvent content, particle concentration, temperature and incubation time) were previously determined with silica nanoparticles as models with similar particle diameter as well as surface chemistry. We demonstrated that under the same conditions MJPs synthesis became trickier, mainly because of the small amount of available supraparticules. This led us to implement new seeded-growth emulsion polymerization conditions. Finally, batches of latex nanoparticles with two or three magnetic patches were obtained, but required further purification steps before investigating their assembly behavior under magnetic field
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Noviana, Eka. "Fabrication of Polystyrene Core-Silica Shell Nanoparticles for Scintillation Proximity Assay (SPA) Biosensors." Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/556865.
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The development of analytical tools for investigating biological pathways on the molecular level has provided insight into diseases and disorders. However, many biological analytes such as glucose and inositol phosphate(s) lack the optical or electrochemical properties needed for detection, making molecular sensing challenging. Scintillation proximity assay (SPA) does not require analytes to possess such properties. SPA uses radioisotopes to monitor the binding of analytes to SPA beads. The beads contain scintillants that emit light when the radiolabeled analytes are in close proximity. This technique is rapid, sensitive and separation-free. Conventional SPA beads, however, are large relative to the cells and made of hydrophobic organic polymers that tend to aggregate or inorganic crystals that sediment rapidly in aqueous solution, thus limiting SPA applications. To overcome these problems, polystyrene core-silica shell nanoparticles (NPs) doped with pTP and dimethyl POPOP were fabricated to produce scintillation NPs that emit photons in the blue region of visible light. The developed scintillation particles are approximately 250 nm in diameter (i.e. 200 nm of core diameter and 10-30 nm of shell thickness), responsive to β-decay from tritium (³H) and have sufficient stability in the aqueous media. DNA hybridization-based SPA was performed to determine whether the scintillation NPs could be utilized for SPA applications. A 30-mer oligonucleotide was immobilized on the polystyrene core-silica shell NPs to give approximately 7.6 x 10³ oligonucleotide molecules per NP and ³H-labeled complementary strand was annealed to the immobilized strand. At the saturation point, increases in scintillation signal due to oligonucleotide binding to the NPs were about 9 fold compared to the control experiments in which no specific binding occurred, demonstrating that the scintillation NPs can be utilized for SPA. Along with the improved physical properties including smaller size and better stability in the aqueous system, the developed scintillation NPs could be potentially useful as biosensors in cellular studies.
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Ducay, Rey Nann Mark Abaque. "Direct Detection of Aggregates in Turbid Colloidal Suspensions." Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1439434385.
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Durrer, Carlo. "Investigation des mécanismes de la bioadhésion de systèmes nanoparticulaires vis-à-vis des muqueuses intestinales." Paris 11, 1994. http://www.theses.fr/1994PA114811.
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Lerch, Simone [Verfasser]. "Uptake mechanism, intracellular trafficking and endo-lysosomal pH monitoring of polystyrene nanoparticles / Simone Lerch." Mainz : Universitätsbibliothek Mainz, 2012. http://d-nb.info/102016414X/34.
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Gonçalves, Ana Patrícia Cordeiro. "Effects of polymeric nanoparticles on fish : a multiparametric approach." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21473.
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Mestrado em Biologia Molecular e CelularThe contamination of aquatic systems with several kinds of debris is an emerging environmental crisis. One of the problems associated with plastic pollution is its persistence. Plastic particles do not disappear, they slowly degraded from macro to micro to nano sizes. Although an increasing number of studies are currently assessing the effects of microplastics in aquatic organisms, the effects or nanoplastics are largely unknown. The present study aims to assess the short-term effects of polymeric nanoparticles in fish alone and in the presence of organic matter. Thus, the effects on ontogenic development were assessed in Danio rerio, a freshwater fish, by exposing fish embryos for 96h to PMMA (concentration range from 2.5 to 202.5 mg/L) and PS (concentration range from 2.5 to 1822.5 mg/L) particles (≈ 50 nm). In addition to ontogenic development, behavioural (distance and time swam as well as thigmotaxis) and biochemical effects (NPT, CAT, GPx, GST, GR and LPO) were also assessed. Effects on Dicentrarchus labrax, a marine fish species, were also assessed after 96h exposure. Assessed parameters included genotoxicity (erythrocytes micronuclei and other nuclear abnormalities and echinocytes shape differences) and effects on antioxidant status and damage (NPT, CAT, GPx, GST, GR and LPO). Overall, the nanoparticles revealed ability to be pernicious to fish, with PMMA presenting a higher toxicity to fish than PS. D. rerio displayed behavioural alterations associated with overall activity and stress responses. In D. labrax, the tested nanoparticles were genotoxic, as demonstrated by the increase of erythrocytes nuclear abnormalities. the assessed biochemical responses were more responsive in gills and liver than intestine with data confirming that nanoplastics have the ability to affect antioxidant status. The present study results are highly relevant as they demonstrate the ability of the tested nanoplastics to affect fish development and behaviour and that they are cytogenotoxic.
A contaminação de sistemas aquáticos com vários tipos de detritos é uma crise ambiental emergente. Um dos problemas associados à poluição com plásticos é a sua persistência. As partículas de plástico não desaparecem, degradaram lentamente de tamanhos macro para micro para nano. Embora atualmente haja um número crescente de estudos que avaliem os efeitos dos microplásticos em organismos aquáticos, os efeitos de nanoplásticos são amplamente desconhecidos. O presente estudo tem como objetivo avaliar os efeitos a curto prazo das nanopartículas poliméricas em peixes e na presença de matéria orgânica. Assim, os efeitos sobre o desenvolvimento ontogénico foram avaliados em Danio rerio, um peixe de água doce, expondo embriões de peixe por 96h a PMMA (intervalo de concentração de 2,5 a 202,5 mg/L) e PS (intervalo de concentração de 2,5 a 1822,5 mg/L) de partículas (≈ 50 nm). Além do desenvolvimento ontogénico, foram também avaliados efeitos comportamentais (distância e tempo de natação, assim como o tigmotaxia) e os efeitos bioquímicos (NPT, CAT, GPx, GST, GR e LPO). Efeitos no Dicentrarchus labrax, uma espécie de peixe marinho, também foram avaliados após a exposição de 96h. Os parâmetros avaliados incluíram genotoxicidade (micronúcleos de eritrócitos e outras anormalidades nucleares e diferenças de forma de equinócitos) e efeitos sobre o estado e dano antioxidante (NPT, CAT, GPx, GST, GR e LPO). No geral, as nanopartículas revelaram a capacidade de ser perniciosas para peixes, com PMMA apresentando maior toxicidade para o peixe do que o PS. D. rerio apresentou alterações comportamentais associadas à atividade geral e respostas de stress. Em D. labrax, as nanopartículas testadas foram genotóxicas, como demonstrado pelo aumento das anormalidades nucleares dos eritrócitos. As respostas bioquímicas avaliadas foram mais sensíveis nas brânquias e no fígado do que no intestino, com dados que confirmam que os nanoplásticos têm a capacidade de afetar o estado antioxidante. Os resultados do presente estudo são altamente relevantes, pois demonstram a capacidade dos nanoplásticos testados para afetar o desenvolvimento e o comportamento dos peixes e que eles são citogenotóxicos.
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Thèvenot, Caroline. "Synthèses, caractérisations et propriétés électrostimulables d'hydrogels composites polyacrylamide-nanoparticules de polystyrène/polyaniline." Pau, 2006. http://www.theses.fr/2006PAUU3028.
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De nouveaux matériaux adaptatifs, des hydrogels composites (HC) électrostimulables ont été élaborés. Ils sont composés d'un réseau de poly(acrylamide) réticulé par du N-N'méthylènebisacrylamide (BisAM) emprisonnant deux types de nanoparticules : (i) de polystyrène (PS) réticulé, (ii) cœur-écorce (CS) constituées d'un cœur de PS et d'une couronne de polymère intrinsèquement conducteur (polyaniline). Ces nanoparticules ont été synthétisées par polymérisation radicalaire en dispersion puis caractérisées. Elles sont de composition et de taille bien définies (400 à 450 nm). La synthèse des HC a été optimisée pour s'affranchir des incompatibilités chimiques entre réseau et nanoparticules. La dispersion de celles-ci dans le réseau a été étudiée par microscopie électronique. Un suivi cinétique en RMN a permis de conclure à la formation d'inhomogénéités du réseau dues à la différence de réactivité entre les monomères (rAM = 0,52, rBISAM = 5,2) et à une conversion quasi-totale. Les HC élaborés ont été caractérisés par rhéologie : ils ont montré une augmentation très importante du G' en fonction de la quantité de nanoparticules incorporées. Par ailleurs, une instrumentation simple, originale, basée sur la reconnaissance de forme a été développée pour permettre le suivi cinétique du gonflement des HC. L'étude menée a démontré que les nanoparticules se comportent en spectatrices sans modifier le processus de gonflement. Deux applications des HC ont été démontrées : les propriétés électrostimulables des HC à base de CS à travers le relargage d'espèces ioniques quand un champ électrique est appliqué (1V) ainsi qu'un effet mécano-électrique pour les HC à base de PSNew électroactives materials, “composite hydrogels” (HC) have been developed. They are composed of a poly(acrylamide) network crosslinked by N-N'methylenebisacrylamide (BisAM) and may contain two kinds of nanoparticles : (i) of crosslinked polystyrene (PS) or (ii) “core-shell” (CS) made of a core of PS with a conducting polymer shell (polyaniline). These aforementioned nanoparticles were synthesized by water dispersion and well characterized. The chemical compositions as well as particle sizes were controlled. The synthesis of HC was optimized by taking into account of the network and the nanoparticles chemical and experimental condition requirements. The particles dispersion into the hydrogel network was also characterized with electronic microscopy. A kinetic study done by NMR showed the formation of inhomogeneities in the network structure due to the values of the reactivity ratios of the monomers (rAM=0,52, rBISAM=5,2) and a quasi-total conversion. The HC were characterized by rheology: it showed a significant increase of G' with the nanoparticles content. Otherwise, a new simple and original system based on pattern recognition was developed to monitor the swelling kinetics of the HC. Swelling equilibrium and diffusion phenomena showed that nanoparticles are not involved in the process of swelling. Two applications were developed: the electroactives properties of HC containing CS particles i. E. Release of ionic species when an electric field is applied (1V) and a mechano-electric effect for the HC containing PS latexes
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Maximilien, Jacqueline. "Studies of the impact of core-shell polystyrene nanoparticles on cell membranes and biomimetic models." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2180.
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L’objectif de ce projet est d’étudier l’interaction de nanoparticules polymères avec les membranes, soit directement sur des cellules entières ou grâce à des modèles membranaires biomimétiques, dans l’optique de valider leur utilisation dans le cadre d’applications biologiques. Des nanoparticules (NPs) polymères cœur/enveloppe avec un diamètre inférieur à 100 nm ont été synthétisés. Cette taille a été choisie afin de leur permettre de pénétrer à travers les membranes plasmiques. Des nanoparticules ayant la même composition chimique mais avec un diamètre hydrodynamique supérieur, de l’ordre de 250 nm, ont été également préparées afin de mettre en évidence l’effet de la taille des particules sur le processus d’internalisation cellulaire. Dans cette thèse, une méthode innovante de synthèse monotope a été développée pour obtenir des NPs coeur-enveloppe, compatibles en milieu aqueux et présentant à leur surface des résidus iniferter. Le coeur est composé de polystyrène avec une taille d’environ 30 nm. Un large éventail de fonctionnalités peut être greffé sur la surface du coeur par polymérisation radicalaire contrôlée en faisant varier différents types de monomères. L’épaisseur de l’enveloppe peut être ajustée en fonction de la concentration en monomère et du temps de polymérisation. Les nanoparticules synthétisées ont été caractérisées par diffusion dynamique de la lumière, par spectroscopie infrarouge à transformée de Fourier, par analyse micro-élémentaire et par microcopie à transmission électronique. Les interactions des NPs à coeur polystyrène et avec des enveloppes de charge neutre et négative ont été étudiées avec des cellules kératinocytes épidermiques humaines néonatales (NHEK), des fibroblastes primaires humains et les cellules HACaT de kératinocytes humains. Les études de cytotoxicité réalisées en utilisant un marquage à l’iodure de propidium et un test à la lactate déshydrogénase n’ont relevé aucune toxicité sur les lignées testées. Cependant, le suivi de la prolifération cellulaire par impédance électrique de substrats cellulaires a indiqué que les nanoparticules anioniques induisent une forte diminution de la prolifération des kératinocytes. L’internalisation cellulaire des NPs a été confirmée par microscopie confocale qui n’indique pas leur colocalisation avec les endosomes précoces, les lysosomes et l’actine. De plus, les données obtenues par triage cellulaire par cytofluorométrie soutiennent qu’un mécanisme énergétiquement-dépendant est mis en œuvre pour l’internalisation des NP neutres, ce qui semble être moins le cas pour les nanoparticules négatives. Les membranes biomimétiques ont été employées afin d’étudier les spécificités des interactions entre nanoparticules et lipides dans des conditions contrôlées. L’étude sur des modèles de vésicules géantes couplée à de la spectroscopie de fluorescence a révélé que les nanoparticules coeur/enveloppe sont capables d’interagir profondément dans la région hydrophobe de la membrane, mais uniquement quand la bicouche lipide est en phase fluide désordonnée. Le mode de pénétration des NPs au travers de la bicouche des vésicules semblent engendrer la formation de pores. Un effet plus prononcé de rigidification de la bicouche a pu être observé lors de l’interaction de nanoparticules chargées négativement avec les bicouches de phosphatidycholines. Cet effet pourrait être attribué à un changement de l’orientation des têtes phosphocholines du à des interactions électrostatiques. En conclusion, les nanoparticules polymère que nous avons synthétisées apparaissent être des outils polyvalents pour les études d’interaction cellulaire et d’imagerie. Ces nanomatériaux peuvent être éventuellement être employés pour la délivrance de médicaments en incorporant les molécules actives dans une enveloppe polymère thermosensible par exempleThis project’s aim was to study polymeric nanoparticle-membrane interactions using both live cells and biomimetic models with the idea to validate such nanoparticles for use in bio-applications. Core-shell polymeric nanoparticles below 100 nm, as this small size is capable of penetrating plasma membranes, were synthesised. Nanoparticles (NPs) with the same chemical composition but with hydrodynamic diameters of ~250 nm, were also prepared in an effort to highlight any effect of NP size on cell internalisation. In this thesis, an innovative method is presented for the synthesis of water-compatible, iniferter-bound polystyrene core shell NPs (~30 nm) using a one-pot synthetic method. A plethora of functionalities could be added to the nanoparticles via shell grafting from the surface of the polystyrene core in the presence of additional monomers via controlled living radical polymerisation. Shell thickness could be tuned as a function of monomer’s concentration and polymerisation time. The nanoparticles were fully characterised by dynamic light scattering, Fourier transform infra-red spectroscopy, microelemental analysis and transmission electron microscopy. Further, the interactions of polystyrene core NPs possessing neutral and anionic shells were investigated using neonatal human epidermal keratinocytes (NHEK), human primary fibroblasts and HaCaT cells. Cytotoxicity studies performed using propidium iodide and lactate dehydrogenase indicated no evidence of cytotoxicity in either cell line. However, cell proliferation monitored by electric cell substrate impedance sensing (ECIS) protocols indicated that anionic nanoparticles induced a dramatic decrease in cell proliferation in keratinocytes. The cellular internalisation of NPs was confirmed by confocal microscopy and no co-localisation was found with early endosomes, lysosomes or actin. Additionally, fluorescence activated cell sorting (FACS) data support the theory that an energy-dependent mechanism is employed for neutral NP internalisation but less so for negatively charged NPs. Biomimetic membrane models were used to investigate specific nanoparticle-lipid interactions under controlled conditions. Employing giant vesicles coupled with fluorescent spectroscopy techniques revealed that core-shell nanoparticles interact deep in the hydrophobic region of bilayers only when the membrane is in the fluid phase. Their mode of entering artificial cells (i.e giant vesicles) appears to cause the formation of pores. Anionic nanoparticles interact with the choline moiety of phosphatidylcholine and confer a rigidifying effect on phosphocholine containing bilayers. Therefore we conclude that the polymeric nanoparticles that we synthesized are versatile tools for cell interaction and imaging studies. These nanomaterials could eventually be applied to drug delivery studies by incorporation of the drug in for instance a thermoresponsive polymeric shell. Furthermore, it is clear that NPs coated with anionic and neutral polymeric shells present a lower toxicity profile than previously reported cationic nanoparticles. Both nanoparticles increase the order lipid bilayer vesicles composed of POPC (the most common glycerophospholipid) in animal and plants. Anionic nanoparticles in particular exhibit a rigidifying effect on POPC lipid bilayers and their mode of entry into cells may be due to the formation of pores which was determined to not induce cell death
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Habel, Azza. "Hairy Nanoparticles with Hydrophobic Polystyrene Cores and Hydrophilic Poly(2-hydroxyethylmethacrylate) Hairs: Synthesis and Characterization." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2019. http://digitalcommons.auctr.edu/cauetds/166.
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The self-assembling properties of a core-shell system are considered to be the most desirable characteristics that allow using this class of polymers in different applications. New hairy nanoparticles (HNPs) with hydrophobic polystyrene cores (PS Cores) and hydrophilic poly(2-hydroxyethylmethacrylate) (PHEMA) shells were synthesized by coupling polymerization methods. Living anionic polymerization in one-pot step was used to synthesize cross-linked polystyrene cores functionalized with hydroxyl groups and atom transfer radical polymerization (ATRP) was then carried out to prepare PHEMA hairs following the grafting form technique. The structural characterizations were carried out by FT-IR and NMR spectroscopy (1H NMR, 13C NMR, APT 13C NMR and 1H 13C HMQC). Dynamic light scattering measurements of obtained HNPs show small increase in the order of nanometers of their hydrodynamic radii after the grafting. Thermal properties were studied by TGA and DSC. The thermal stability of PS cores was affected by functionalization with the hydroxyl group. However, the stability of the PS core was not affected by grafting of PHEMA on their surfaces. DSC thermograms of the HNPs shows two distinct transition temperatures corresponding to glass transition temperatures (Tg) of a PS phase and of a PHEMA phase indicating the formation of a hydrophobic-hydrophilic phase separated system. SEM and AFM were utilized to study the morphologies and self-assembly of nanoparticles. The self-assembled HNPs morphologies were dependent on the solvents used.
Complexes of the synthesized HNPs and R- or S-mandelic acid were prepared and characterized by circular dichroism (CD) and AFM. CD was used to study the induced chiral properties of the complexes. The CD spectra indicated the formation of enantiomeric chiral structures and the AFM images show toroidal self-assembled structures. Polymer blends of polystyrene functionalized with hydroxyl groups and PHEMA show different morphology and different thermal properties than the core-shell HNP system.
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Drillières, Sophie. "Synthèse de nanoparticules réticulées de poly(styrène) de type "coeur brosse" à structure contrôlée." Le Mans, 1999. http://www.theses.fr/1999LEMA1013.
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Un procede de synthese de particules de poly(styrene) reticulees et greffees, de structure controlee et modulable, a ete developpe. La strategie d'elaboration de ces nanoparticules de type cur-brosse est couramment appelee core-first et from. Elle a consiste a preparer des curs porteurs de groupes capables d'amorcer la polymerisation radicalaire pseudo-vivante du styrene, puis a elaborer les greffons par polymerisation du styrene a partir de ces curs reactifs. Deux types de groupements amorceurs ont ete introduits : l'un, thermosensible, derive du tempo, et l'autre, photosensible, du n,n-diethyldithiocarbamate. La realisation des greffons par polymerisation radicalaire controlee du styrene a necessite une etape prealable de modelisation. Dans le cas de l'amorcage de la polymerisation a partir du n-benzyloxy-2,2,6,6-tetramethyl-1-piperidine (derive du tempo), il a ete montre que le mecanisme de polymerisation n'est pas pseudo-vivant du fait de la lenteur de la cinetique de decomposition de l'amorceur. En revanche, la polymerisation du styrene amorcee par l'iniferter n,n-diethyldithiocarbamate de 4-methylbenzyle presente les caracteristiques d'une polymerisation pseudo-vivante : sans reaction de transfert ni de terminaison irreversible. Des nanoparticules porteuses de groupes amorceurs de structure analogue a celle des composes modeles ont ete preparees par copolymerisation en emulsion suivie, dans certains cas, d'une etape de modification chimique. Les greffons ont ensuite ete prepares par polymerisation du styrene a partir de ces curs reactifs redisperses dans un solvant organique. Le greffage des curs porteurs de groupes du type tempo s'accompagne de la formation d'homopolymere (chaine libre) par amorcage thermique spontane de la polymerisation du styrene. Lors du greffage de curs porteurs de fonctions n,n-diethyldithiocarbamate la presence d'homopolymere n'a pas ete detectee et une gamme de nanoparticules chevelues a pu etre elaboree et caracterisee.
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Delgado, Anne-Paula De Sousa. "Latex de polystyrène à propriétés de surface contrôlées par adsorption de copolymères à base de dextrane et de poly(oxyéthylène)." Vandoeuvre-les-Nancy, INPL, 2000. http://www.theses.fr/2000INPL066N.
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Différents dérivés hydrophobisés du dextrane (dextrane-phenoxy, dexph) et des copolymères dextrane-phenoxy-poly(oxyethylene) (dexph POE) ont été utilisés pour modifier les propriétés de surface de nanoparticules de polystyrène. Les dérivés dexph se déposent sous la forme de couches interfaciales relativement denses, tandis que les copolymères dexph POE forment une double-couche moins compacte, constituée d'un coeur de dextrane et d'une couronne externe de POE. La structure des couches adsorbées est essentiellement déterminée par le nombre de points de contact entre le dextrane et la surface du polystyrène, ainsi que par les répulsions des chaines de POE entre elles et avec celles de dextrane. Elle joue un rôle déterminant sur la stabilité des suspensions, en présence de sels ou sous l'effet de la température. Pour éviter la désorption de polymère en présence d'espèces hydrophobes telles que les protéines, les couches déposées ont été réticulées par voie chimique. Concernant les particules recouvertes des copolymères dexphpoe, les protéines sont capables de déformer et de pénétrer la couche épaisse de POE, puis de s'adsorber à la surface du polystyrène en déplaçant certains segments de dextrane. Au contraire, les recouvrements à base des dérivés dexph sont moins perméables aux protéines, à condition que le nombre de points d'ancrage entre le dextrane et le polystyrène soit suffisamment élevé. Nous avons également montre que la concanavaline a (cona), qui présente des sites de fixation spécifiques du glucose, s'adsorbe de façon spécifique sur les particules dont la surface externe est constituée de dextrane. Enfin, les dérivés du dextrane ont également été utilisés comme stabilisants pendant la polymérisation en émulsion du styrène. Les résultats préliminaires montrent qu'il est ainsi possible d'obtenir des particules dont la surface est hydrophile et non-attractive vis-à-vis des protéines. Comme précédemment, le nombre de points de contact entre le dextrane et la surface du polystyrène est un paramètre déterminant.
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Barnoud, Jonathan. "Interaction entre modèles de membranes biologiques et nanoparticules, une études par simulation moléculaire." Paris 7, 2014. http://www.theses.fr/2014PA077260.
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Les membranes biologiques jouent un rôle crucial pour les cellules. Elles constituent leurs barrières externes et internes. Ces membranes régulent les flux de matière, d'information et d'énergie au sein des cellules. Les fonctions d'une membrane sont intimement liées à sa composition, altérer de cette composition peut altérer les fonctions membranaires. Un tel changement de composition peut être du à l'ajout de molécules exogènes, tels des médicaments ou des polluants. L'effet de ces molécules sur les membranes n'est pas toujours compris. De plus, l'environnement chimique d'une molécule affecte son comportement ; ainsi, une membrane lipidique affecte les molécules exogènes qui y sont intégrées. Les détails moléculaires de ce phénomène restent méconnus. Ici, j'ai utilisé des simulations de dynamique moléculaire pour étudier l'effet de nanoparticules de carbone sur des modèles membranaires, ainsi que l'effet des membranes sur les nanoparticules. Je montre que des nanoparticules de polystyrène altèrent des propriétés membranaires, notamment l'organisation latérale des lipides. Cette organisation est affectée par d'autres molécules hydrophobes dont le fullerene C60. Cet effet dépend des molécules en jeu : les molécules aromatiques stabilisent la séparation des lipides tandis que les molécules aliphatiques mélangent les lipides. Je montre aussi que le fullerene C60 déstabilise le surfactant pulmonaire. Dans un second temps, je montre que les membranes lipidiques affectent la dimérisation de peptides transmembranaires ; puis je caractérise comment le fullerene C60 tend moins à s'agréger dans une membrane lipidique que dans des alcanes pourtant similaires chimiquementBiological membranes have a crucial role in cells as they form their outer boundary with the plasma membrane, but also the inner boundaries as they border the organelles. Membranes regulate the flow of matter, information, and energy in all cell compartments. A membrane functions are tightly attached to its composition, so alterations of a membrane composition can alter the membrane function. Such change in composition can be due to the addition of exogenous molecules as drugs or pollutants. How these exogenous molecules alter membrane properties is not always known nor understood. In addition, the chemical environment of a molecule affects the its behavior; therefore, exogenous molecules embedded in a lipid membrane can be affected by the membrane. The molecular details of this effect on small molecules are not fully understood. In this thesis, I used molecular dynamics simulations to investigate the effect of carbon nanoparticules on the properties of membrane models, and the effect of these membranes on nanoparticules. I showed that polystyrene nanoparticules alter some membrane properties, especially the lipid lateral organization. Other hydrophobie molecules affect lipid lateral organization. This effect depends on the molecule: aromatic molecules, including C60 fullerene, stabilize the separation of the lipids; on the contrary, aliphatic molecules mix the lipids. C60 fullerene also destabilize lung surfactant. I investigated the effect of membrane properties on the dimerization of transmembrane peptides. Finally I characterized how C60 fullerene aggregate less in a lipid membrane than in chemically similar bulk alkanes
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Walker, Richard John. "Behaviour of nanocolloidal particles on mica : investigations using atomic force microscopy." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4633.
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In this thesis we used atomic force microscopy (AFM) to investigate systematically the behaviour of both electrostatically stabilised silica and sterically stabilised polystyrene (PS) colloidal systems on freshly cleaved mica substrates. For the silica colloidal nanoparticles we explored the effect of colloidal suspension concentration, particle size, and different application techniques on both the adsorption behaviour and subsequent structuring of the particles. For the PS colloidal nanoparticles we explored concentration effects and experimented with both dip-coating and droplet application techniques. We showed that silica nanoparticles adsorbed onto mica via irreversible adsorption that possessed lateral mobility due to the weak attraction between the nanoparticles and the substrate, facilitating subsequent capillary structuring of the nanoparticles during drying. We associated the effects of volume fraction with Debye screening, and kinetics effects with particle size and volume fraction. We also successfully imaged a partially dried film and showed the role of convective/capillary forces in the structuring of the nanoparticles. Studies with variations in particle size generated a number of different topography structures; with dewetting phenomena observed for 10 nm nanoparticles and the formation of crystalline structures for 100 nm nanoparticles. Spin coating techniques were used to produce even larger crystalline structures of nanoparticles. Size dependent ordering occurred for low concentration samples due to the polydispersity of the colloidal suspension. We showed that acceleration can affect interparticle spacing. We also studied the role of rotational speed on the crystallinity of the particle configurations and showed how fine tuning of rotational speed can generate large scale monolayer crystalline formations of nanoparticles.
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Greven, Anne-Catherine [Verfasser], and Dušan [Akademischer Betreuer] Palić. "Polycarbonate and polystyrene nanoparticles act as stressors to the innate immune system of fathead minnows (Pimephales promelas, Rafinesque 1820) / Anne-Catherine Greven. Betreuer: Dušan Palić." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1084582937/34.
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Shuwaikan, Mohammed Salem. "Investigation of the uptake, co-localisation, biological effects, and toxicity mechanism(s) of carboxyl-modified polystyrene nanoparticles (COO-PS-NPs) onto human bronchial epithelial (BEAS-2B) cells." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6155/.
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Carboxyl-modified polystyrene nanoparticles (COO-PS-NPs) have many potential applications, for example drug-delivery systems, but their toxicity remains poorly assessed. In the current study, characterisation, uptake and toxicity of two sized COO-PS-NPs in cultured BEAS-2B lung epithelial cells were investigated. The 20nm sized COO-PS-NPs tended to aggregate heavily in the cell culture media yielding larger aggregates, in contrast the 100nm COO-PS-NPs were stable. Electron and confocal microscopy demonstrated that COO-PS-NPs rapidly accumulate in vesicle-like structures within cells and fluorescent organelle co-staining showed the presence of 20nm COO-PS-NPs in mitochondria and the 100nm COO-PS-NPs in Golgi apparatus. Cellular studies revealed that COO-PS-NPs cause GSH depletion and induce ROS generation resulting in oxidative stress. Studies in a cell-free system showed that COO-PS-NPs directly deplete levels of GSH in solution. Size- and concentration-dependent DNA strand breaks (by comet assay) were also observed and both 20nm and 100nm COO-PS-NPs induced caspases-3/7 activation in a Ca2+ independent manner, however a significant decrease in cell viability was observed only at high concentrations of 20nm COO-PS-NPs. In summary, this in vitro study demonstrated that toxicity of the 20nm COO-PS-NPs is mediated by oxidative stress after co-localisation to the mitochondria and that further studies are needed to assess the safety of COO-PS-NPs.
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Cinausero, Nicolas. "Etude de la dégradation thermique et de la réaction au feu de nanocomposites à matrice PMMA et PS." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2009. http://tel.archives-ouvertes.fr/tel-00382965.
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En dépit de leurs propriétés uniques, les polymères sont très sensibles à la température et sont susceptibles de s'enflammer en présence d'une source de chaleur et au contact de l'air. Afin de remplacer les additifs retardateurs de flammes halogénés, soumis à certaines inquiétudes et restrictions, nous avons étudié de nouveaux systèmes retardateurs de flammes à base d'oxydes minéraux nanométriques concernant deux polymères : le poly(méthacrylate de méthyle) (PMMA) et le polystyrène (PS). Trois stratégies ont été mises en place. Nous avons examiné dans un premier temps l'influence des oxydes d'aluminium et de silicium nanométriques sur les propriétés ignifuges et les mécanismes de stabilité thermique des nanocomposites à matrices thermoplastiques. Divers paramètres ont été évalués comme le taux d'incorporation, la composition chimique des oxydes et le type de matrice polymère. L'impact de la modification de surface des nanoparticules sur la réaction au feu des composites a été également analysé. Les traitements de surface des oxydes concernent des greffages de molécules organiques de faible masse molaire, le dépôt de couches inorganiques et le greffage d'oligomères. Enfin, des combinaisons d'additifs phosphorés et de nanocharges, vierges ou modifiées, ont mis en évidence des synergies notables sur la réaction au feu. L'étude du procédé d'ignifugation des composites a été réalisée notamment par l'analyse approfondie des résidus charbonnés.
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Lepcio, Petr. "Příprava a charakterizace samouspořádávacích polymerních nanokompozitů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217011.
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Polymerní nanokompozity na bázi polyhedrálních oligomerních silsesquioxanů (POSS) představují slibnou oblast výzkumu, která potenciálně může využít samouspořádávní při navrhování nových materiálů. Tato diplomová práce popisuje postup přípravy oktafenyl-POSS/PS, oktafenyl-POSS/PMMA a oktamethyl-POSS/PS systémů a charakterizaci jejich termomechanických vlastností v pevné fázi a reologických vlastností v roztoku. Získané výsledky jsou diskutovány s přihlédnutím k teoriím zabývajících se stavem disperze nanočástic.
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Mathlouthi, Chourouk. "Étude des propriétés thermodynamiques et dynamiques des polymères confinés en géométrie nanoparticules." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI035/document.
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L’effet du confinement sur les propriétés physiques des polymères est un sujet d’une importance à la fois fondamentale et académique et est le centre d’un débat scientifique soutenu. La relation entre la transition vitreuse (Tg) et la dynamique des polymères en confinement est notamment le centre d’un débat controversé au sein de la communauté scientifique depuis les deux dernières décennies. Alors que la transition vitreuse mesurée par expansion thermique est diminuée de manière remarquable en films minces, sa dynamique alpha est invariante : ce phénomène est aperçu comme une rupture avec la loi de superposition temps température. Pour chercher l’origine des controverses scientifiques qui en résultent et répondre aux questions posées dans ce débat, on s’intéresse, dans ce travail de recherche, aux propriétés calorifiques des polymères à base de nanoparticules, avec une surface spécifique élevée, confinés en structure compacte. Bien que cette géométrie présente quelques avantages comme une importante surface spécifique et une méthode de préparation générant moins de contraintes résiduelles, relativement peu d’études ont été réalisées sur cette géométrie de confinement comparé à celles portant sur les films minces.L’objectif principal de cette thèse est d'étudier le comportement de la Tg et de la dynamique du polystyrène confinés sous forme de nanoparticules dans une structure compacte où les particules sphériques sont séparées par des vides et en les comparants aux polymères massiques correspondants. Nous étudions la cinétique de fermeture des vides inter-particules dans cette géométrie compacte en fonction de la surface libre pour extraire la dynamique α du polystyrène confiné. Nous avons utilisé les résultats des thermogrames de calorimétrie à balayage différentielle (DSC) de ces particules pour obtenir des informations sur la capacité calorifique Cp. Nous montrons que la capacité calorifique du polystyrène confiné est similaire à celle du polymère massique correspondant dans le régime vitreux et s’écarte de ce comportement entre Tg -30°C et Tg. Cet écart devient de plus en plus important avec l’augmentation de la surface libre. Ce phénomène a été attribué à l'existence d'une couche mobile à la surface libre du polystyrène ou à l'existence d'une couche possédant un coefficient de dilatation important. Par contre, nous montrons également que la dynamique α du polymère confiné présente le même comportement que le polymère massique dans cette gamme de température.Le deuxième volet de cette thèse vise à étudier le mécanisme de vieillissement vitreux du polystyrène confiné dans la géométrie des particules en structure compacte. Nous avons calculé la recouvrance enthalpique lors du vieillissement du polystyrène dans les cas confiné et massique à des différents températures et temps de vieillissement. Nous montrons que le vieillissement vitreux dépend de la méthode de préparation du polymère et est fortement affecté par le confinementThe impact of confinement on the physical properties of polymers is an important topic for both fundamental and academic aspects and has gathered an intensive interest within the polymer physics community. In particular the relationship between the glass transition (Tg) and the dynamic of confined polymers has remained the center of a controversial debate over the past two decades. While the glass transition measured by thermal expansion is remarkably decreased in thin films, the alpha dynamic of polymers was found to be invariant, which can be seen as incoherence with the time-temperature superposition. To search the origin of these controversies and answer the questions posed in this debate, we focus the study on the thermal properties of confined polystyrene in the compact structure with a high surface area such as nanoparticles. Even though the particles geometry exhibit several advantages such as higher free surface and mild processing method, only few studies have been carried out on it compared to that on the thin films.The main objective of this thesis is to investigate the behavior of Tg and the dynamics of confined polystyrene in particles in the close packed structure, where the spherical particles are separated by voids, and to compare them to their corresponding bulk. We investigate the kinetic of void closure to quantify the α-dynamic of confined polystyrene in particles. We extract information about the heat capacity (Cp) from differential scanning calorimetry (DSC) thermograms. We show that the Cp of confined polystyrene is similar to that of bulk in the glassy regime and deviates from it between Tg -30 ° C and Tg. The magnitude of this deviation increases with increasing the free surface area. This was interpreted by the existence and the propagation of a mobile layer on the free surface or the existence of a zone with higher expansion coefficient. On the other hand, the α-dynamic probed via the void closure in the area where Cp increases was found to exhibit a bulk behavior.A second objective of this thesis is to investigate the physical aging of confined polystyrene in particles in the glassy regime. We quantify the enthalpy recovery during aging of both confined polystyrene and their corresponding bulk at various temperatures and aging times. We show that the physical aging process depends on the processing history of the polymer and is highly affected by the confinement
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Santos, Fábio Júnior Mota dos. "Espumas de poliestireno impregnadas com nanopartículas de ouro para a redução do p-nitrofenol." Universidade Estadual da Paraíba, 2017. http://tede.bc.uepb.edu.br/jspui/handle/tede/3026.
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There are countless researches related to the treatment of waste water because they contain large amounts of recalcitrant chemicals, such as p-Nitrophenol widely used in the industry in dyeing leather. Because it is a very toxic substance even at low concentrations, its total removal and / or transformation into other less polluting substances becomes an urgent environmental issue. Gold nanoparticles because they have great catalytic potential besides being non-toxic can somehow contribute to the minimization of the environmental effects caused by nitrophenols. Reactions using homogeneous catalysts are not very feasible in some cases, they present great difficulty during the separation of the catalysts from the rest of the reaction medium. In this context, this work aimed at the development of a catalyst based on gold nanoparticles impregnated in polystyrene foams an industrial waste, using thermally induced phase separation as the method of obtaining the same. It is then tested for catalytic reduction of p-Nitrophenol. The gold nanoparticles of different diameters were obtained using different synthesis conditions and characterized by spectrophotometry in the region of the visible for the size measurement, whereas for the already impregnated foams the characterization techniques used were the scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric (TG) analysis and thermogravimetric analysis (DTG). The catalyst was tested using as a model reaction the reduction of p-Nitrophenol to p-Aminophenol, the whole process was accompanied by UV-vis and what is concluded is a variation in the reaction velocities as a function of the variation of the particle size present in the foam and / or their concentrations therein.
Já são inúmeras as pesquisas relacionadas ao tratamento de águas residuais pelo fato de as mesmas conterem grandes quantidades de substancias químicas recalcitrantes, a exemplo do p-Nitrofenol muito utilizado na indústria no tingimento de couro. Por se tratar de uma sustância muito tóxica mesmo em baixas concentrações sua total remoção e/ou transformação em outras menos poluentes, torna-se uma questão ambiental urgente. As nanopartículas de ouro por apresentarem grande potencial catalítico além de não serem tóxicas, podem de alguma forma contribuir para a minimização dos efeitos agressivos ao ambiente causados por nitrofenóis. Reações que utilizam catalisadores homogêneos são pouco viáveis em alguns casos, apresentam grande dificuldade durante a separação do catalisados do restante do meio reacional. Nesse contexto esse trabalho objetivou o desenvolvimento de um catalisador a base de nanopartículas de ouro impregnadas em espumas de poliestireno um rejeito industrial, utilizando como método de obtenção para o mesmo a separação de fases induzida termicamente. Para então testa-lo na redução catalítica do p-Nitrofenol. As nanopartículas de ouro de diferentes diâmetros foram obtidas utilizando-se diferentes condições de síntese e caracterizadas através da espectrofotometria na região do visível para a aferição do tamanho, enquanto que para as espumas já impregnadas as técnicas de caracterização utilizadas foram a microscopia eletrônica de varredura (MEV), difração de raio-X (DRX), analise termogravimétrica (TG) a derivada da analise termogravimétrica (DTG). O catalisador foi testado utilizando como reação modelo a redução do p-Nitrofenol a p-Aminofenol, todo o processo foi acompanhado por UV-vis e o que se conclui é uma variação nas velocidades das reações em função da variação do tamanho de partículas presente na espuma ou/e de suas concentrações na mesma.
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Ramaye, Yannic. "Optimisation des latex magnétiques utilisés dans les biotechnologies." Paris 6, 2004. http://www.theses.fr/2004PA066423.
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Catrouillet, Sylvain. "Nanocylindres supramoléculaires formés par association de polymères à blocs promoteurs de liaisons hydrogène." Thesis, Le Mans, 2014. http://www.theses.fr/2014LEMA1006/document.
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L’objectif de cette thèse était d’obtenir des nanocylindres de Janus, particules présentant deux faces différentes, parchimie supramoléculaire. De telles particules seraient très intéressantes comme stabilisant d’émulsions mais sont trèsdifficiles à synthétiser. Notre idée a consisté à utiliser des systèmes auto-associatifs de type bisurée et trisurée, capablesde s’organiser en solution en structures cylindriques par le biais de liaisons hydrogène directionnelles. En décorant cesfonctions de deux bras polymères incompatibles, des propriétés de Janus sont attendues.Tout d’abord, l’étude de l’auto-association en solution de bisurées et trisurées décorées de deux bras polyisobutylène(PIB) identiques a montré que la formation de longs cylindres nécessitait des motifs trisurées s’associant assez fortementpour contrebalancer la gêne stérique des bras PIB. Pour des trisurées décorées de deux bras polystyrène (PS), il estnécessaire de synthétiser des bras PS très courts pour former des cylindres anisotropes, ce qui a été possible en ayantrecours à la polymérisation radicalaire contrôlée.Les résultats précédents ont permis d’identifier une trisurée décorée par un bras PIB et un bras PS court comme candidatidéal à l’élaboration de nanocylindres de Janus. La synthèse d’une telle molécule a été mise au point. Son organisation ensolution a été étudiée par diffusion de lumière, révélant que la taille des objets est principalement contrôlée par les brasPS encombrants. Bien que l’incompatibilité forte entre le PS et le PIB, vérifiée en masse, laisse espérer leur ségrégationde phase en solution, le caractère Janus des particules reste une perspective essentielle de ce travailThe goal of this thesis was to obtain Janus self assembled nanocylinders. These particles present two different faces andwould be very interesting as emulsion stabilizers but are very difficult to synthesize. Our idea was to use self assemblingsystems based on bisureas and trisureas. These systems are able to self-assemble in solution into cylindrical structuresthrough directional hydrogen bonds. Decorating them by two incompatible polymer arms should lead to Janus properties.First, the study of the self-assembly in solution of bisureas and trisureas decorated by two identical polyisobutylene (PIB)arms has demonstrated that the formation of long cylinders required trisureas, able to develop strong enough hydrogenbonds to counterbalance the steric hindrance of the PIB arms. Trisureas decorated by two identical polystyrene (PS) armsrequired the synthesis of very short PS arms in order to form anisotropic cylinders. This could be achieved usingcontrolled radical polymerization.The previous results allowed the identification of a trisurea decorated by one PIB arm and one short PS arm as idealcandidate for the elaboration of Janus nanocylinders. The synthesis of such a molecule was developed. Its self-assemblyin solution was studied by light scattering, revealing that the size of the objects was mainly controlled by the bulky PSarms. Although the strong incompatibility between PS and PIB, which was evidenced in the bulk, gives hope that thesepolymers will phase segregate in solution, the Janus character of these particles remains an essential outlook of thiswork
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Chavez, Panduro Elvia Anabela. "Synchrotron Nano-scale X-ray studies of Materials in CO2 environment." Thesis, Le Mans, 2014. http://www.theses.fr/2014LEMA1010/document.
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Le travail qui est présenté dans ce manuscrit est le résultat d'une série d'expériences qui ont été effectuées à la fois à l'Université du Maine (IMMM Le Mans) et aux lignes de lumière lD10 et lD02 de l'ESRF (Grenoble) où j'ai passé la moitié de mon temps. Le projet que j'ai travaillé pendant trois ans a été principalement orienté sur l'étude des nanomatériaux qui ont été exposés au CO2 supercritique en utilisant de diffusion des rayons X. Par conséquent une partie de ce travail a été consacrée à la description des propriétés de ce fluide supercritique et comment il interagit avec des matériaux tels que les polymères par exemple. Les matériaux analysés ont été le polystyrène sous forme de film et des ilots, ensuite des matériaux meso-structures avec des tensioactifs fluorés et finalement le carbonate de calcium. Due à la taille nanométrique de tous ces matériaux, les techniques de rayons X qui ont été largement utilisés dans ce travail étaient Small angle X-ray scattering (SAXS), Grazing Small angle X-ray scattering ( (GISAXS) et X-ray reflectivity (XRR)The work that is presented in this manuscript is the result of a series of experiments that were performed both at the Université du Maine (IMMM Le Mans) and at the ID10 and ID02 beam lines of the ESRF (Grenoble) where I have equally spent half of my time. The project I have been working on for three years was mostly oriented on the study by means of X-ray scattering probes of nanomaterials that were exposed to supercritical CO2. As a result another part of this work will be also dedicated to describing the properties of this supercritical fluid and how it interacts with materials such as polymers for instance. The analyzed materials were thin film and small island of polystyrene, then materials mesostructures using fluoro-surfactants and finally calcium carbonate. Due to the nanoscale of these materials, the X-ray probes that were extensively used in this work were Small Angle X-ray scattering (SAXS), Grazing Incidence Small Angle X-ray Scattering (GISAXS) and X-ray Reflectivity (XRR)
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Dru, Delphine. "Synthèse, optimisation et caractérisation des nouvelles architectures catalytiques pour une application en pile à combustible PEMFC." Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2277/document.
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Ces travaux de recherche s'inscrivent dans le développement de nouveaux catalyseurs pour les piles à combustible de type PEMFC. L'objectif est d'améliorer le transfert de charges et de matières au sein des électrodes afin d'améliorer la durabilité des matériaux. Nous avons développé des catalyseurs qui permettent la transposition de la phénoménologie du point triple à l'échelle moléculaire. Le greffage de polymères conducteurs protoniques à la surface de nanoparticules de platine a été réalisé afin d'obtenir des complexes catalytiques nano-composites, comportant le catalyseur au platine, un conducteur protonique et un conducteur électronique. L'ensemble des matériaux issus de cette première étape ont été caractérisé en demi-cellule électrochimique afin de déterminer les catalyseurs les plus actifs et les plus sélectifs. Les matériaux les plus prometteurs ont enfin été testés en mono-cellule PEMFC de 5 cm² et 25 cm² afin de déterminer d'une part les performances in situ et d'autre part la durabilité des matériaux. Les électrodes nano-composites, formulées sans Nafion®, ont des caractéristiques équivalentes aux systèmes commerciaux. En effet, elles fournissent une densité de puissance maximale de 1 W.cm-2 et une durabilité de 20 µV.h-1 sur 300 h. Ces électrodes formulées sans composé fluoré permettent le recyclage du platine par pyrolyseThis research work is within the scope of new catalysts for PEM fuel cells. The objective is to decrease the platinum amount in the electrode and to promote mass and electronic transfers, in order to improve the durability of the systems. We developed catalysts that enable the implementation of the phenomenology of the triple phase boundary at the molecular scale. The fieldwork concerns the grafting of proton conducting polymers (PSS) on the platinum nanoparticles surface in order to obtain nanocomposite catalysts. All synthetized materials are characterized in electrochemical half-cell, in order to determine the most active and the most selective catalyst. Then, the best catalytic complexes are tested in PEMFC 5 cm² and 25 cm² single-cell to determine in situ performance and materials durability. The properties of the nanocomposites electrodes formulated without Nafion®, are equivalent to commercial systems. Indeed, they provide a maximum power density of 1 W.cm-2 and a durability of 20 µV.h-1 during 300 h. These electrodes formulated without fluorinated compound allow platinum recycling by pyrolysis
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Oropeza, María Verónica Carranza. "Síntese e caracterização de nanopartículas núcleo-casca de poliestireno e polimetacrilato de metila obtidas por polimerização em emulsão sem emulsificante e fotoiniciada." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-16032012-133346/.
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O objetivo do trabalho foi sintetizar e caracterizar nanopartículas de poliestireno e polimetacrilato de metila com morfologia núcleo-casca obtidas através da polimerização em emulsão sem emulsificante em dois estágios e através da fotopolimerização. Nos experimentos avaliou-se a influência de diferentes condições operacionais baseadas em fatores cinéticos sobre os dois estágios da polimerização. As condições avaliadas para o primeiro estágio de preparação de núcleos foram: a temperatura do processo, a concentração de iniciador e de monômero, e o efeito de agentes modificadores de superfície (sal, co-monômero e reticulante). Para o segundo estágio de formação da casca as condições avaliadas foram: a concentração e o regime de alimentação de monômero. Os resultados experimentais mostraram que uma relação de co-monômero e reticulante é a melhor alternativa para preparar núcleos estáveis e de diâmetros pequenos. Assim, o revestimento uniforme dos núcleos é obtido no segundo estágio e com isso a morfologia núcleo-casca em equilíbrio é alcançada. Dois sistemas experimentais (reator convencional e reator fotoquímico) foram propostos e avaliados na sua eficiência para obter partículas com este tipo de morfologia no segundo estágio (formação do revestimento). As diversas técnicas de caracterização indicaram a formação de morfologia núcleo-casca na maioria dos casos estudados para os dois sistemas propostos. Por sua vez, as técnicas espectroscópicas (NIR e Raman) permitiram o monitoramento do processo em tempo real e a elaboração de modelos de calibração que correlacionaram o crescimento do tamanho da partícula núcleo. Da mesma forma, os fatores termodinâmicos foram estudados para predizer a morfologia final esperada nos sistemas. Os resultados, experimental e predito são comparados e discutidos em termos de aspectos chave envolvidos no controle da morfologia da partícula.This work aimed at studying the synthesis and characterization of core-shell nanoparticles of polystyrene and polymethylmethacrylate obtained in a two-stage emulsifier-free emulsion polymerization and photopolymerization. The influence of different operational conditions based on kinetic factors was experimentally evaluated. In the first stage (seed preparation) the process temperature, initiator and monomer concentrations and the effect of surface-modifier agents (acids, salts, co-monomers and crosslinker) were investigated; similarly in the second stage, the concentration and feeding regime of monomer were evaluated with respect to the shell formation. Experimental results showed that both, crosslinker and co-monomer are the best alternative to achieve a stable seed with small diameter; hence, with this core, uniform coating is obtained in the second stage and core-shell morphology is reached. In order to evaluate the efficiency of the preparation of core-shell particles, two experimental systems (conventional and photochemical reactor) were studied. Different characterization techniques indicated that in most of the cases studied particles with the desired core-shell morphology were formed. The use of spectroscopic techniques NIR and Raman were tested for the real-time monitoring of the process using adequate calibration models developed to correlate the average size of the growing core particle with the spectra. In the same way, thermodynamic factors were used to predict the expected final morphology of the particles. Experimental and predicted results were compared and discussed in terms of the key aspects involved in the control of the particle morphology.
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Lepcio, Petr. "Efekt submikrometrických rysů na reologii polymerních nanokompozitů." Doctoral thesis, Vysoké učení technické v Brně. CEITEC VUT, 2018. http://www.nusl.cz/ntk/nusl-391876.
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Polymerní nanokompozity (PNCs) mají slibnou budoucnost jako lehké funkční materiály zpracovatelné aditivními výrobními technologiemi. Jejich rychlému rozšíření však brání silná závislost jejich užitných vlastností na prostorovém uspořádání nanočástic (NP). Schopnost řídit disperzi nanočástic je tak klíčovým předpokladem pro jejich uplatnění ve funkčních kompozitech. Tato práce zkoumá přípravu polymerních nanokompozitů v modelové sklotvorné polymerní matrici roztokovou metodou, technikou schopnou vytvářet prostorové uspořádání nanočástic řízené strukturními a kinetickými parametry přípravného procesu. Prezentované výsledky popisují rozdíly mezi změnami rheologického chování roztoku polystyrenu při oscilačním smyku s vysokou amplitudou (LAOS) vyvolanými nanočásticemi. Výsledky vedou k závěru, že vysoce-afinní OP-POSS nanočástice při nízkých koncentracích dobře interagují s PS a tvoří tuhé agregáty, zatímco nízko-afinní OM-POSS nanočástice za těchto podmínek neovlivňují deformační chování polymerních řetězců. Dále byla pozornost zaměřena na vliv použitého rozpouštědla na uspořádání nanočástic v SiO2/PMMA a SiO2/PS nanokompozitech, který je v literatuře prezentován jako parametr řídící prostorové uspořádání nanočástic v pevném stavu. Důraz byl kladen na kvalitativní rozdíly mezi „špatně dispergovanými“ shluky nanočástic, které byly na základě rheologie a strukturální analýzy (TEM, USAXS) identifikovány jako polymerními řetězci vázané nanočásticové klastry a dva typy agregátů, jeden termodynamického a druhý kinetického původu. Jednotlivé druhy agregátů se vyznačují odlišnými kinetikami vzniku a rozdílnými vlastnostmi jak mezi sebou, tak v porovnání s dispergovanými nanočásticemi. Pozorované typy disperze nanočástic byly kvantitativně posouzeny podle svých rheologických vlastností během roztokové přípravy, podle kterých byla vyhodnocena míra adsorpce polymeru na povrch nanočástic a atrakce ve vypuzeném objemu. Výsledky byly porovnány s teorií PRISM. Důležitost uspořádání nanočástic byla demonstrována na porovnání teplot skelných přechodů různých struktur při stejném chemickém složení.
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Tallec, Kevin. "Impacts des nanoplastiques et microplastiques sur les premiers stades de vie (gamètes, embryons, larves) de l'huître creuse Crassostrea gigas Surface functionalization determines behavior of nanoplastic solutions in model aquatic environments, in Chemosphere 225, June 2019 Nanoplastics impaired oyster free living stages, gametes and embryos, in Environmental Pollution 242 (Part B), November 2018 Constraints and priorities for conducting experimental exposures of marine organisms to microplastics, in Frontiers in Marine Science 5(252), July 2018 Cellular responses of Pacific oyster (Crassostrea gigas) gametes exposed in vitro to polystyrene nanoparticles, in Chemosphere 208, October 2018." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0103.
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Depuis 70 ans, les débris plastiques dont la fin de vie a été négligée par les sociétés humaines s’accumulent dans les océans. L’évaluation des effets engendrés par cette contamination ubiquitaire est une préoccupation majeure, notamment au regard des micro- et potentiels nanoplastiques (MNP ; < 5 mm) du fait de leur biodisponibilité pour la plupart des organismes marins. L’objectif de cette thèse était de déterminer les effets des MNP sur les jeunes stades de vie d’une espèce ingénieure des habitats côtiers, l’huître creuse Crassostrea gigas. Les impacts des MNP sur ces jeunes stades sont apparus dépendants de la taille des particules. Le rapport surface/volume important des nanosphères de polystyrène (nano-PS ; 50 nm) a favorisé les interactions avec les gamètes et embryons, induisant une inhibition de la fécondation et de l’embryogénèse tandis que les microsphères (0,5 et 2 μm) n’ont causé aucun effet phénotypique visible. La toxicité des nano-PS est apparue dépendante de leurs propriétés de surface (e.g groupements chimiques, charge) qui dirigent leur agrégation dans l’eau de mer et les interactions avec les membranes biologiques. Les nano-PS cationiques, qui restent à l’échelle nanométrique dans l’eau de mer, sont à l’origine des effets toxiques les plus marqués. L’exposition embryonnaire à une dose non létale a notamment diminué les performances larvaires et modulé la réponse de la génération suivante à une réexposition embryonnaire. Toutefois, ces effets néfastes sont observés à des concentrations numéraires supposément non-représentatives de l’environnement actuel (la quantité de NP n’étant pas caractérisée en mer à ce jour), suggérant un risque limité des micro- et nanosphères de polystyrène sur les jeunes stades de C.gigas. Les prochaines études devront tenir compte de la complexité et de la réalité des MNP environnementaux (e.g. polymères, formes, contaminants adsorbés, concentrations) sur plusieurs générations de bivalves dans le but d’appréhender plus précisément le risque pour les écosystèmes côtiersFor 70 years, mismanaged plastic waste accumulates in the oceans. Risk assessment of this contamination is a major concern, especially regarding micro- and presumably nanoplastics (MNP; <5 mm) which are bioavailable for most marine species. The objective of this thesis was to assess adverse effects of MNP to early life stages of the oyster Crassostrea gigas, a key engineer species in coastal ecosystems. MNP toxicity on oyster young stages depended on the particle size. The high surface area- to - volume ratio of polystyrene nanobeads (nano- PS; 50 nm) promoted their reactivity and interactions with biological membranes of gametes and embryos, leading to an inhibition of the fertilization and embryogenesis success while 0.5 and 2 μm polystyrene beads had any detectable effects. The nano-PS toxicity depended on the particle surface properties (e.g. surface functionalization and charge) which govern their aggregation in seawater and affinity with biological membranes. Furthermore, cationic nano- PS which remained at nanometric scale in seawater, had the highest toxic potential to oyster gametes and embryos. Embryonic exposure to these particles at a non-lethal dose reduced first generation larval performances and modulated larval growth at the second generation in response to the same embryonic exposure. All adverse effects were observed at supposedly unrealistic environmental concentrations (no in situ data exists on NP), suggesting low risk of polystyrene beads to oyster early life stages. Future studies will have to take into account the complexity and reality of MNP in oceans (e.g. polymer and shape diversity, concentrations, contaminants adsorption) to assess effects on bivalve species across generations in order to establish more accurately the risks for coastal environments
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Lo, Chi-Jen, and 羅啟仁. "Synthesis of polystyrene nanoparticles and microstructures of nanoparticle film." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/57087692174209711224.
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碩士國立中正大學
化學工程所
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Nanoparticles have major applications in the fields of food, printing, liquid crystal and drug release. These particles can also generate ordered structures, so called photonic crystals (PCs), which can enhance the optical property in the device such as fiber, laser and wave guide. Among all fabrication approaches, two processes are generally used: lithography and self-assembly. Lithography has been recognized as an excellent method to produce large area defect-free 3D PCs due to its scalability and controllability, but this process is limited by its expensive equipment that ordinary laboratory cannot afford. On the other hand, self-assembly becomes a better method in fabrication of 3D PCs in the lab. In order to control the sizes of polystyrene (PS) nanoparticles, we carried out the PS synthetic experiments. PCs were then prepared by sonication-assisted casting (SAC). Additionally, microstructure evolution during solvent evaporation is of fundamental interest. Therefore, we designed an environmental chamber that can maintain suitable experimental conditions. This thesis is mainly divided into three parts: synthesis of PS nanoparticles, fabrication of PCs by SAC and design of environmental chamber. Surfactant-free emulsion polymerization was used to synthesize PS nanoparticles of diameters between 30-1000 nm, by changing the concentration of styrene, 4-styrenesulfonic acid sodium salt, and sodium chloride. They served as monomers, nuclei, and the salt that varied the ionic strength, respectively. Diameter and distribution of particles were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). PCs made of PS nanoparticles with diameters between 200 nm-1000 nm was fabricated by SAC. Different structures such as hexagonal, cubic, and random packing can be obtained, by adjusting concentration, volume and solvent of precursor. High-quality PCs, using 100 μL and 24 mg/mL of precursor, were prepared on the 1 cm2 glass substrate. SEM cross-section image shows the face centered cubic (FCC) array. Peak position of the UV-Vis spectrum (absorption > 30%) agrees with the Bragg’s-Snell law. Additionally, the diameter and quality of PCs can also be qualitatively determined from the scattering stripes by home-built of solid state film light scattering (SSL-LS). Environmental chamber is comprised of a temperature controller and an automatic dispensing system. The temperature can be controlled from room temperature to 300℃, and a steady experimental environment can be reached in 20 min. This chamber is able to dispense a desired volume of precursor and to maintain constant dry speed. We can, in theory, utilize an in-situ grazing incidence x-ray scattering (IsGIXS) with high-flux synchrotron radiation source to study structure evolution of thin film formation during solvent evaporation. The further applications of PCs are the ultimate goal. For example, utilize it as a template to fabricate porous films or exploit the unique property of photonic band gap of PCs to enhance the absorption of particular wavelength in material, more investigations need to be done.
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Yi, i.-Ling Liu, and 劉怡伶. "Synthesis,Characterization of Magnetite/polystyrene core-shell nanoparticle." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/27xs32.
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Chiu, Guo-Wei, and 邱國維. "Polystyrene sulfonic acid-Magnetic NanoParticle for Cell Level Hyperthermia Treatment." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/728dum.
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Liu, Kun-Chi, and 劉昆奇. "Plasmon-Mediated Trapping Force of Gold Dimer Array on Polystyrene Nanoparticle." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/c2hjr7.
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碩士國立臺灣大學
應用力學研究所
105
This thesis studies for the 1D nano-gold dimer (NGD) array, which is irradiated by a linearly polarized Gaussian beam, on a polystyrene nanoparticle (NP) and trapping it. By using multiple-multipole expansions method (MMP) and Maxwell stress tensor to compute the electromagnetic (EM) field and the optical force and optical torque. This thesis use quantitative research method to analyze the phenomenon of optical force and optical torque, and compare with the experience. The numerical results show that in the far field, which the distance of NGD array and NP is longer than λ/2, the stationary point is dominated by Gaussian beam. In the other hand, if this case is in the near field, the stationary point is dominated by the NGD array. We find that the polystyrene NP is trapped by an optical force vortex, which results in spinning and floating in the oil, even the NGD moves away from the Gaussian beam axis. When the NGD is far away from the beam axis, the gradient force of Gaussian beam will make the NP going to the next NGD, we call this motion ‘‘jumping motion’’. And then, the movement as a step-like motion, is happened.
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Tsai, Hsin Chih, and 蔡欣芝. "Preparation of Polystyrene Composite With Controllable Gold Nanoparticle Size via Anionic Polymerization." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/70073474097178271036.
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碩士國立中正大學
化學工程研究所
101
This work mainly takes advantage of anionic polymerization to synthesize SCH3-polystyrene and SCH3-polystyrene-SH. Basically speaking，we use n-butyllithium to activate one side of dimethyl sulfide to form activated complex ion. Then we add styrene monomers to proceed polymerization. Finally, we use ethylene sulfide as end-functionalization agent to quench the polymer chain. Most importantly, we make use of the sulfur atom to form gold nanoparticle/ polystyrene nanocomposite with the addition and reduction of gold solution. We observe the effect on the size of gold nanoparticles of not only the amount of polymer but also the type of functional group. The composite is analyzed by GPC、1H-NMR、13C-NMR、EDS、TEM、UV-Vis、TGA and DSC for details.
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Chou, Chen-Yu, and 周振宇. "Quantum Dot-sensitized Solar Cells: Investigation on Polystyrene-templated TiO2 and ZnO Nanowire/Nanoparticle Photoanodes." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/01485100837331033424.
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Liu, Kuan-Ting, and 劉冠廷. "Optical Trapping of Gold Nanostructure on Polystyrene Bead and Photothermal/Optomechanical Deformation of Gold Nanoparticle." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/bze64y.
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碩士國立臺灣大學
應用力學研究所
107
This thesis is divided into two parts: the first part is related to the optical trapping of gold nanostructure, and the second the photothermal and optomechanical deformation of gold nanoparticle (NP). We adopt the multiple-multipole expansions method to calculate the electromagnetic field of light-mater interaction, and then utilize Maxwell’s stress tensor to obtain the optical traction and force upon the object for both parts. In the first part, we study the optical trapping on a polystyrene bead by a gold nanostructure (dimer, trimer or tetramer), irradiated by a linearly polarized (LP) Gaussian beam. The streamline field of optical force for a dimer shows that the stagnation point of noncontact-mode trapping can follow the dimer to move if the polarization direction is not perpendicular to the orientation of dimer. However, the noncontact-mode trapping ability of a dimer depends on the polarization direction very much. In contrast, the trapping ability of a trimer and tetramer is not sensitive to the polarization. The results of a 2D dimer array or 1D trimer array also show that if the gap coupling in the cluster is induced by a LP light the stagnation point of noncontact mode will follow the array to move. The step-like jump of the trapped NP will occur as the array continuously moves away from the optical axis. In the second part, we study the photothermal and optomechanical deformation of a gold NP under the irradiation of a LP Gaussian beam. Due to the photothermal heating, the gold NP becomes softened. In addition, the optomechanical effect, the optical traction exerted upon the surface of NP, causes the deformation. Our results show that the photothermal effect softens NP to become semi-solid, and the optical stretching tractions at the two ends of NP elongate it. As a result, the NP becomes a nanorod (NR). In addition, optical pinching traction at the middle circumference of NR causes a necking. Subsequently, the elongated NR will be cut into two smaller NRs by the optical traction. If we continuously irradiate the NRs, liquid gold is induced, and the surface tension will spherify these NRs.
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Chandran, Sivasurender. "Structure and Dynamics of Binary Mixtures of Soft Nanocolloids and Polymers." Thesis, 2013. http://etd.iisc.ernet.in/2005/3458.
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Binary mixtures of polymers and soft nanocolloids, also called as polymer nanocomposites are well known and studied for their enormous potentials on various technological fronts. In this thesis blends of polystyrene grafted gold nanoparticles (PGNPs) and polystyrene (PS) are studied experimentally, both in bulk and in thin films. This thesis comprises three parts; 1) evolution of microscopic dynamics in the bulk(chapter-3),2) dispersion behavior of PGNPs in thin and ultra thin polymer matrices (chapter-4) 3) effect of dispersion on the glass transition behavior (chapter-5).
In first part, the state of art technique, x-ray photon correlation spectroscopy is used to study the temperature and wave vector dependent microscopic dy¬namics of PGNPs and PGNP-PS mixtures. Structural similarities between PGNPs and star polymers (SPs) are shown using small angle x-ray scatter¬ing and scaling relations. We find unexpected (when compared with SPs) non-monotonic dependence of the structural relaxation time of the nanoparticles with functionality (number of arms attached to the surface). Role of core-core attractions in PGNPs is shown and discussed to be the cause of anomalous behavior in dynamics. In PGNP-PS mixtures, we find evidence of melting of the dynamically arrested state of the PGNPs with addition of PS followed by a reentrant slowing down of the dynamics with further increase in polymer frac¬tion, depending on the size ratio(δ)of PS and PGNPs. For higher δ the reen¬trant behavior is not observed with polymer densities explored here. Possible explanation of the observed dynamics in terms of the presence of double-glass phase is provided. The correlation between structure and reentrant vitrifica¬tion in both pristine PGNPs and blends are derived rather qualitatively.
In the second part, the focus is shifted to miscibility between PGNPs and polymers under confinement i.e., in thin films. This chapter provide a compre¬hensive study on the different parameters affecting dispersion viz., annealing conditions, fraction of the added particles, polymer-particle interface and more importantly the thickness of the films. Changes in the dispersion behavior with annealing is shown and the need for annealing the films at temperatures higher than the glass transition temperature of the matrix polymers is clearly elucidated. Irrespective of the thickness of the films( 20 and 65 nm) studied, immiscible particle-polymer blends unequivocally prove the presence of gradi¬ent in dynamics along the depth of the films. To our knowledge for the first time, we report results on confinement induced enhancement in the dispersion of the nanoparticles in thin polymer films. The enhanced dispersion is argued to be facilitated by the increased free volume in the polymer due to confinement as shown by others. Based on these results we have proposed a phase diagram for dispersibility of the nanoparticles in polymer films. The phase diagram for ultra thin films highlights an important point: In ultra thin films the particles are dispersed even with grafting molecular weight less than matrix molecular weight.
In the third part, we have studied the glass transition of the thin films whose structure has been studied earlier in the earlier part. Non-monotonic variation in glass transition with the fraction of particles in thin films has increased our belief on the gradient in the dynamics of thin polymer films. En¬hanced dispersion with confinement is captured with the enhanced deviation in glass transition temperature of ultra thin films. Effect of miscibility param¬eter on Tgis studied and the results are explained with the subtle interplay of polymer-particle interface and confinement.
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Huang, Jing-Ting, and 黃敬庭. "Preparation of Polystyrene Nanoparticles with Core-shell Structure." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/x3v2u3.
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碩士國立高雄應用科技大學
化學工程與材料工程系碩士在職專班
106
Core-shell polystyrene nano-spheres were successfull prepared by emulsion polymerization. In this system, styrene monomer, cross-linking agent divinyl-benzene, hydrophobic organic material isooctane and n-hexane were used as an oil phase. The water phase contains the deionized water, emulsifier, co-emulsifier and initiator (potassium persulfate; KPS). Polymerization reactions for core-shell structure of polystyrene nano-spheres were conducted in an appropriate temperature. Sphere morphology was detected by FE-SEM. The particle size distribution was in the range of 100 to 200 nm. Core-shell structure was also observed by TEM. Effect of HLB values (hydrophile-lipophile babance) of emulsifiers on particle size was also investigated by a particle size analyser (PSA)
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Hsieh, Hui-Ling, and 謝蕙蔆. "Synthesis and Characterization of Nanoparticles-Embedded Polystyrene Micro Particles." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/46913419413289346116.
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碩士國立臺灣科技大學
化學工程系
103
This work points to a relatively easy and convenient two-step process for the sequential synthesis of iron-coating carbon nanoparticles (Fe0@C) and of polystyrene (PS) microparticles with samarium(Ⅲ) oxide (Sm) and Fe0@C. Fe0@C was synthesized by the chemical reduction method and hydrothermal carbonization method at different ratios of FeCl3‧6H2O and citric acid. The result showed that the ratio of [FeCl3‧6H2O]: [Citric acid] = 1: 5 was better than the others, since iron nanoparticles were homogeneously dispersed in carbon matrix and can be attracted by magnet. PS microspheres were synthesized by suspension polymerization in water system. The morphology of polystyrene microspheres was observed using optical microscopic and scanning electron microscopic (SEM) studies. When 2,2-azobis-isobutyronitrile (AIBN) of 10 mg was chosen, the PS particles were large in number and were observed as a sphere with a narrow size distribution. Materials of Sm, PS and Fe0@C were mixed to synthesize PS/Sm and PS/Sm/Fe0@C by polymerization. In thermal gravimetric analysis (TGA), the weight loss curve of PS/Sm showed that after 450 °C, the PS was burned off and PS/Sm weight remained 6.1 %, attributed to the Sm. The morphology of PS/Sm/Fe0@C was similar between optical microscopic images and SEM images. The PS/Sm/Fe0@C particles had a diameter between 20~50 μm, but the smaller particles with amorphous shape coexisted. According to the research results, PS/Sm/Fe0@C particles should be suitable for using cancer therapy and deliver it to the tumors via its blood supply.
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Chou, Chin-Hui, and 周菁慧. "Synthesis and Properties of Platinum/ Polystyrene Core-Shell Nanoparticles." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/36x5f2.
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碩士國立臺北科技大學
有機高分子研究所
95
In this research, we design a series of organic interfaces and link molecular, SH base group that this molecular includes one end and can absorb chemistry with platinum nanoparticles; another end can as initial alkyl bromide of ATRP of polyreaction, link two sense alkyl spacer of base. The molecule absorbs and assembles on the surface in Pt particle, make use of it in order to disperse the platinum nanoparticlse in the organic solvent, for instance toluene, THF, chloroform, etc.. It is to regard NaBH4 as the reducing agent, reduce H2PtCl6•xH2O into a platinum particle that platinum particle is synthetic. And then disperse the platinum particle in the organic solvent with this molecule. Then utilize ATRP method carry on surface-initiated polymerization to polymerize polystyrene on surface of platinum nanoparticles. After that regard SDS (sodium dodecyl sulfate) as the surfactant to disperse the platinum nanoparticlse in the water. Finally, the Pt particle were characterized by NMR, IR, TEM, XRD and DLS.
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Hu, Chih-Wei, and 胡致維. "SIZE-CONTROL OF AU NANOPARTICLES IN POLYSTYRENE VIA ANIONIC POLYMERIZATION." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/75551080893544063196.
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碩士國立中正大學
化學工程所
93
The aim of this work is to prepare the polystyrene with thiol terminal group (PS-SH) and use this functionalized polystyrene to stabilize and control the size of gold nanoparticles. The PS-SH was first synthesized via an anionic polymerization. Then, PS-SH was mixed with HAuCl4·3H2O in THF solvent in the presence of a reducing agent, super hydride. Upon the reduction of Au+ to Au atoms, the thiol groups of the polymer molecules were bonded onto the gold surface and a polymeric nanocomposite with well-distribute nanogold particles material was thus formed. Depending on the molar ratio of thiol to Au+ and the molecular weight of the polymer, the particle size was controlled within a range of 3~30nm with little aggregation. 1H-NMR、13C-NMR、TEM、XPS、TGA、DSC and UV-VIS were used to investigate the physical properties of the nanocomposite.
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Lai, Yu-ting, and 賴玉婷. "STABILIZATION OF AU NANOPARTICLES WITH A STAR-SHAPED POLYSTYRENE SYNTHESIZED ANIONICALLY." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/06936370474344295388.
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碩士國立中正大學
化學工程所
95
The aim of this work is to prepare a star polystyrene containing gold nanoparticles,(PS)star -AuNPs,via anionic polymerization.The synthesis uses the arm-first method that controls the number of arms of (PS)star by varying the molar ratio of DVB to n-BuLi.Afterwards,we functionalize the living (PS)star by ethylene sulfide(ES).The resulting star polystyrene with thiol terminal groups.(PS)star-SH was then mixed with HAuCl4•3H2O in THF solvent in the presence of the reducing agent, super hydride. Upon the reduction of Au+ to Au atoms, the thiol groups of the polymer molecules were bonded onto the gold surface and a polymeric nanocomposite with well-distribution nanogold particles was thus formed. Compared with the linear counterpart,(PS)linear-AuNP, (PS)star-AuNPs has a better size distribution of gold nanoparticles and prevent more effectively the aggregation of gold nanoparticles. 1H-NMR、13C-NMR、TEM、XPS、TGA、DSC and UV-VIS have bene used to investigate the physical properties of the nanocomposite material.
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Yang, Hong-ying, and 楊泓穎. "The Arrangement and Application of Gold Nanoparticles in Polystyrene-block-Polybutadiene Epoxidation." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/44345367920595523893.
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碩士國立中山大學
材料與光電科學學系研究所
98
This study uses the combination of block copolymer and metal nanoparticles to array ordered structure and specific physical properties such as optics, electricity and magnetism. In this first part, 2-phenylethanethiol was used as the monolayer-protected gold nanoparticles (nps) and dispersed in block copolymer PS-b-PB-E thin film. Two different methods are compared, the first method was PS-b-PB-E thin film by partial crosslinked treatment then the 2-phenylethanethiol of monolayer-protected gold nanoparticles soaked into PS-b-PB-E thin film. The second method was blended gold nps within PS-b-PB-E directly. We found that the first method was better than second method which had arrangement dispersedly. The analyses of UV-VIS, TEM, and SAXS measurement are able to provide the positive evidence to characterize the dispersion of gold nps in diblock copolymer thin film. In the second part, we design to manufacture the multi-nanoholes golden electrode, which has many application in catalysis, selective transit function and fuel cell electrode. We use the PS-b-PB-E copolymer as the spherical micelle, which is the templates and then micelle surface reaction in mercaptane (S-H) function. Gold nps will use the exchange stabilizing ligands method in the micelle surface layer, and the porous gold electrode material by way of the heat treatment step.