Littérature scientifique sur le sujet « Emulsione Pickering »
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Articles de revues sur le sujet "Emulsione Pickering"
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Fu, Lipei, Qianli Ma, Kaili Liao, Junnan An, Jinmei Bai et Yanfeng He. « Application of Pickering emulsion in oil drilling and production ». Nanotechnology Reviews 11, no 1 (3 décembre 2021) : 26–39. http://dx.doi.org/10.1515/ntrev-2022-0003.
Texte intégralRésumé :
Abstract When surfactant is used as emulsifier, the stability of emulsion is often greatly reduced with the influence of reservoir conditions (temperature, pressure, salinity, etc.), which shortens the validity period of emulsion. Pickering emulsion has a wide range of applications in the oil and gas field due to its advantages of good stability and easy regulation. In this article, the formation, stabilization mechanism, and influencing factors of Pickering emulsions were introduced, and the application status and prospects of Pickering emulsions in oil and gas field were summarized. It was pointed out that Pickering emulsion has many advantages and important research value when applied in deep strata and complicated reservoirs. It is expected that this article can effectively reflect the application value of Pickering emulsion in oil and gas field and promote the application of Pickering emulsion in petroleum industry.
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Cho, Yu-Jin, Dong-Min Kim, In-Ho Song, Ju-Young Choi, Seung-Won Jin, Beom-Jun Kim, Jin-Won Jeong, Chae-Eun Jang, Kunmo Chu et Chan-Moon Chung. « An Oligoimide Particle as a Pickering Emulsion Stabilizer ». Polymers 10, no 10 (27 septembre 2018) : 1071. http://dx.doi.org/10.3390/polym10101071.
Texte intégralRésumé :
A pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA)-based oligoimide (PMDA-ODA) was synthesized by a one-step procedure using water as a solvent. The PMDA-ODA particles showed excellent partial wetting properties and were stably dispersed in both water and oil phases. A stable dispersion was not obtained with comparison PMDA-ODA particles that were synthesized by a conventional two-step method using an organic solvent. Both oil-in-water and water-in-oil Pickering emulsions were prepared using the oligoimide particles synthesized in water, and the size of the emulsion droplet was controlled based on the oligoimide particle concentration. The oligoimide particles were tested to prepare Pickering emulsions using various kinds of oils. The oil-in-water Pickering emulsions were successfully applied to prepare microcapsules of the emulsion droplets. Our new Pickering emulsion stabilizer has the advantages of easy synthesis, no need for surface modification, and the capability of stabilizing both oil-in-water and water-in-oil emulsions.
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Zhang, Xingzhong, Dan Wang, Shilin Liu et Jie Tang. « Bacterial Cellulose Nanofibril-Based Pickering Emulsions : Recent Trends and Applications in the Food Industry ». Foods 11, no 24 (15 décembre 2022) : 4064. http://dx.doi.org/10.3390/foods11244064.
Texte intégralRésumé :
The Pickering emulsion stabilized by food-grade colloidal particles has developed rapidly in recent decades and attracts extensive attention for potential applications in the food industry. Bacterial cellulose nanofibrils (BCNFs), as green and sustainable colloidal nanoparticles derived from bacterial cellulose, have various advantages for Pickering emulsion stabilization and applications due to their unique properties, such as good amphiphilicity, a nanoscale fibrous network, a high aspect ratio, low toxicity, excellent biocompatibility, and sustainability. This review provides a comprehensive overview of the recent advances in the Pickering emulsion stabilized by BCNF particles, including the classification, preparation method, and physicochemical properties of diverse BCNF-based particles as Pickering stabilizers, as well as surface modifications with other substances to improve their emulsifying performance and functionality. Additionally, this paper highlights the stabilization mechanisms and provides potential food applications of BCNF-based Pickering emulsions, such as nutrient encapsulation and delivery, edible coatings and films, fat substitutes, etc. Furthermore, the safety issues and future challenges for the development and food-related applications of BCNFs-based Pickering emulsions are also outlined. This work will provide new insights and more ideas on the development and application of nanofibril-based Pickering emulsions for researchers.
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Zhang, Junjia, Jieyu Zhu, Yujia Cheng et Qingrong Huang. « Recent Advances in Pickering Double Emulsions and Potential Applications in Functional Foods : A Perspective Paper ». Foods 12, no 5 (26 février 2023) : 992. http://dx.doi.org/10.3390/foods12050992.
Texte intégralRésumé :
Double emulsions are complex emulsion systems with a wide range of applications across different fields, such as pharmaceutics, food and beverage, materials sciences, personal care, and dietary supplements. Conventionally, surfactants are required for the stabilization of double emulsions. However, due to the emerging need for more robust emulsion systems and the growing trends for biocompatible and biodegradable materials, Pickering double emulsions have attracted increasing interest. In comparison to double emulsions stabilized solely by surfactants, Pickering double emulsions possess enhanced stability due to the irreversible adsorption of colloidal particles at the oil/water interface, while adopting desired environmental-friendly properties. Such advantages have made Pickering double emulsions rigid templates for the preparation of various hierarchical structures and as potential encapsulation systems for the delivery of bioactive compounds. This article aims to provide an evaluation of the recent advances in Pickering double emulsions, with a special focus on the colloidal particles employed and the corresponding stabilization strategies. Emphasis is then devoted to the applications of Pickering double emulsions, from encapsulation and co-encapsulation of a wide range of active compounds to templates for the fabrication of hierarchical structures. The tailorable properties and the proposed applications of such hierarchical structures are also discussed. It is hoped that this perspective paper will serve as a useful reference on Pickering double emulsions and will provide insights toward future studies in the fabrication and applications of Pickering double emulsions.
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Potoroko, Irina, Irina Kalinina et Anastasia Paimulina. « Properties Stability Forecast of Pickering Emulsion Structured by Bioactive Plant Particles ». Food Industry 7, no 4 (21 décembre 2022) : 111–19. http://dx.doi.org/10.29141/2500-1922-2022-7-4-13.
Texte intégralRésumé :
The new generation design and production of food systems with the declared physicochemical and bioactive properties is impossible without the use of science-grounded approaches based on a complex combination of experimental studies and quantum calculation algorithms. One of the promising food systems, actively studied by the scientists around the world, are the Pickering emulsions. Pickering emulsions act as an emulsion food products basis and a fortifying complex that can be an effective system for delivering biologically active substances to the human body. The study aimed at obtaining predictive solutions to achieve the properties stability of the Pickering emulsions stabilized by plant sonochemically structured bioactive particles. As a result of applying quantum chemical calculations using the online resource chemosophia.com and visualization programs, the authors obtained a stable molecular interaction complex between a lipophilic biologically active substance and linseed oil triglyceride, confirming the possibility of such composite development. As a procedure result for fucoidan biologically active substance depolymerization using ultrasonic low-frequency exposure, there was a reduction in the fucoidan particles size by 20-40 times. This led to an increase in its stabilizing properties in the Pickering emulsion based on linseed oil. The scanning electron microscopy results enabled to reveal that the biologically active stabilizer concentration of the Pickering emulsion occurred at the phase boundary predominantly. The resulting Pickering emulsions can act as the basis of emulsion food products enriched with the valuable fatty acid composition of linseed oil and biologically active substances used to stabilize the emulsion.
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Sanchez-Salvador, Jose Luis, Ana Balea, M. Concepcion Monte, Angeles Blanco et Carlos Negro. « Pickering Emulsions Containing Cellulose Microfibers Produced by Mechanical Treatments as Stabilizer in the Food Industry ». Applied Sciences 9, no 2 (21 janvier 2019) : 359. http://dx.doi.org/10.3390/app9020359.
Texte intégralRésumé :
Pickering emulsions are emulsions stabilized by solid particles, which generally provide a more stable system than traditional surfactants. Among various solid stabilizers, bio-based particles from renewable resources, such as micro- and nanofibrillated cellulose, may open up new opportunities for the future of Pickering emulsions owing to their properties of nanosize, biodegradability, biocompatibility, and renewability. The aim of this research was to obtain oil-in water (O/W) Pickering emulsions using cellulose microfibers (CMF) produced from cotton cellulose linters by mechanical treatment through a high-pressure homogenizer. The O/W Pickering emulsions were prepared with different O/W ratios by mixing edible oil (sunflower oil) with water containing CMF at concentrations of up to 1.0 wt%. The apparent viscosity of the separated emulsion phase was measured. Results showed the feasibility of using low concentration of CMF for preparing and stabilizing Pickering emulsions, with the apparent viscosity of the emulsion phase increasing 60–90 times with respect to the sunflower oil, for a shear rate of 1 s−1. In addition, theoretical nutrition facts of the emulsions were calculated and compared with other fats used in foods, showing that they can be a promising low-calorie product containing dietary fiber, replacing trans and saturated fats in foods.
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Sy, Papa Mady, Sidy Mouhamed Dieng, Alphonse Rodrigue Djiboune, Mamadou Soumboundou, Fatou Diop Cisse, Mouskeba Sire Dieme, Boucar Ndong et al. « O/W Pickering emulsion stabilized by magnesium carbonate particles for drug delivery systems ». Journal of Drug Delivery and Therapeutics 13, no 2 (15 février 2023) : 47–54. http://dx.doi.org/10.22270/jddt.v13i2.5925.
Texte intégralRésumé :
This study investigates the formulation of surfactant-free Pickering emulsions that release a drug at a specific pH to improve its oral bioavailability. The stabilizing particles composed of magnesium carbonate particles. Pickering oil-in-water emulsions stabilized with magnesium carbonate particles and encapsulating a hydrophobic drug model (ibuprofen) were formulated using a high-energy process with rotor-stator turbo mixer (IKA® T25 digital ultra-Turrax). The experimental approach explored the impact of all formulation parameters, dispersed phase and amount of magnesium carbonate particles on the physicochemical properties of Pickering emulsions. The O/W Pickering emulsion was characterized by a methylene blue test, pH and conductivity measurements, and droplet size determination. In addition, Pickering emulsions stabilized by magnesium carbonate particles have the advantage of being destabilized in acidic medium leading to the release of the active principle via the droplets. The acidic medium release study (pH equal to 1.2) showed ibuprofen release as a function of initial droplet loading and saturation concentration. In the simulated intestinal medium at pH equal to 6.8, we found a better release of ibuprofen from emulsions that already had saturation in an acid medium. Thus, the interest of these Pickering emulsions lies on the fact that their non-toxicity and magnesium carbonate particles allow destabilization of the emulsions and release of the drug. These emulsions not only protect patients from the side effects of acid-based drugs, but also contribute to increase the bioavailability of these acidic drugs.
Keywords: emulsion -Pickering-magnesium carbonate- ibuprofen-oral bioavailability
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de Carvalho-Guimarães, Fernanda Brito, Kamila Leal Correa, Tatiane Pereira de Souza, Jesus Rafael Rodríguez Amado, Roseane Maria Ribeiro-Costa et José Otávio Carréra Silva-Júnior. « A Review of Pickering Emulsions : Perspectives and Applications ». Pharmaceuticals 15, no 11 (15 novembre 2022) : 1413. http://dx.doi.org/10.3390/ph15111413.
Texte intégralRésumé :
Pickering emulsions are systems composed of two immiscible fluids stabilized by organic or inorganic solid particles. These solid particles of certain dimensions (micro- or nano-particles), and desired wettability, have been shown to be an alternative to conventional emulsifiers. The use of biodegradable and biocompatible stabilizers of natural origin, such as clay minerals, presents a promising future for the development of Pickering emulsions and, with this, they deliver some advantages, especially in the area of biomedicine. In this review, the effects and characteristics of microparticles in the preparation and properties of Pickering emulsions are presented. The objective of this review is to provide a theoretical basis for a broader type of emulsion, in addition to reviewing the main aspects related to the mechanisms and applications to promote its stability. Through this review, we highlight the use of this type of emulsion and its excellent properties as permeability promoters of solid particles, providing ideal results for local drug delivery and use in Pickering emulsions.
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TOUZOUIRT, Saida, Fetta KESSAL, Chanez BELAIDI et Dihia BOULHALFA. « INFLUENCE OF PROCESSING PARAMETERS ON RHEOLOGICAL BEHAVIOR OF BENTONITE-BASED PICKERING EMULSION ». Journal of Drug Delivery and Therapeutics 8, no 5 (12 septembre 2018) : 442–47. http://dx.doi.org/10.22270/jddt.v8i5.1903.
Texte intégralRésumé :
The aim of this work is to study the impact of processing parameters on the rheological properties of Pickering emulsions containing bentonite particles, CTAB, NaCl and soybean oil. Emulsification experiments were performed using mixing and homogenization at different speeds for 10 minutes. The effects of stirring speed and homogenization were investigated to determine the best conditions for producing a suitable Pickering emulsion for the intended application. In order to assess the influence of processing parameters on the Pickering emulsion rheological behavior average droplet size was measured and rheological tests were performed on all the emulsions samples. The rheological behavior of these emulsions is modeled by Casson's law. Results show that the stirring speed first decreases the average size of the droplets, and then an effect on the initial viscosity is observed. Increasing the stirring speed increases the values of the initial viscosity in contrast to the infinite viscosity which is influenced by the homogenization speed. On the other hand, these processing parameters significantly affect the values of the yield strength.
Keywords: stirring speed, speed homogenization, rheological properties, Pickering emulsion.
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Ren, Gaihuan, Zhanzhao Li, Dongxu Lu, Bo Li, Lulu Ren, Wenwen Di, Hongqin Yu, Jianxin He et Dejun Sun. « pH and Magnetism Dual-Responsive Pickering Emulsion Stabilized by Dynamic Covalent Fe3O4 Nanoparticles ». Nanomaterials 12, no 15 (28 juillet 2022) : 2587. http://dx.doi.org/10.3390/nano12152587.
Texte intégralRésumé :
Herein, we describe pH and magnetism dual-responsive liquid paraffin-in-water Pickering emulsion stabilized by dynamic covalent Fe3O4 (DC-Fe3O4) nanoparticles. On one hand, the Pickerinfigureg emulsions are sensitive to pH variations, and efficient demulsification can be achieved by regulating the pH between 10 and 2 within 30 min. The dynamic imine bond in DC-Fe3O4 can be reversibly formed and decomposed, resulting in a pH-controlled amphiphilicity. The Pickering emulsion can be reversibly switched between stable and unstable states by pH at least three times. On the other hand, the magnetic Fe3O4 core of DC-Fe3O4 allowed rapid separation of the oil droplets from Pickering emulsions under an external magnetic field within 40 s, which was a good extraction system for purifying the aqueous solution contaminated by rhodamine B. The dual responsiveness enables Pickering emulsions to have better control of their stability and to be applied more broadly.
Thèses sur le sujet "Emulsione Pickering"
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TAGLIARO, IRENE. « NOVEL COLLOIDAL APPROACH TO PREPARE HIGHLY-LOADED SILICA-BASED ELASTOMERIC NANOCOMPOSITES ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2019. http://hdl.handle.net/10281/241175.
Texte intégralRésumé :
L’industria degli pneumatici si prefigge di indagare possibili strategie sintetiche per ridurre l’impatto ambientale durante tutto il ciclo di vita dello pneumatico, attraverso l’uso di materiali sostenibili e lo sviluppo di tecniche innovative che riducano il consumo di energia e le emissioni di CO2.
In questo contesto, questa progetto di dottorato è focalizzato sulla preparazione di nanocompositi eco-sostenibili attraverso l’uso di un approccio colloidale per aumentare la dispersione di filler idrofilici, in linea con i nuovi requisiti di sostenibilità delle politiche europee.
L’approccio colloidale punta a produrre nanocompositi con filler idrofilici, la cui efficiente dispersione attraverso tecniche di miscelazione tradizionali rimane difficoltosa a causa della scarsa compatibilità con la matrice organica. Questa tecnica si focalizza sull’incremento della dispersione di filler senza alcuna modifica superficiale, con l’eliminazione delle poveri prodotte durante il mescolamento con significativi benefici per l’ambiente e i lavoratori.
Due diversi approcci colloidali sono stati utilizzati: i) una tecnica di miscelazione in lattice e ii) una in situ polimerizzazione in emulsione per la produzione di nanocompositi altamente caricati contenenti filler come silice e sepiolite (Sep), questi ultimi sono considerati filler promettenti nell’ambito del rinforzo dei polimeri grazie alla loro struttura fibrosa e all’elevato rapporto di forma.
La concentrazione, la carica, la forma dei nanofiller a base silicea sono stati studiati come parametri rilevanti per la stabilizzazione e destabilizzazione di lattici a base di poliisoprene naturale e sintetico.
Una efficiente procedura di miscelazione in lattice è stata messa a punto per produrre compositi eco-sostenibili, chiamati masterbatches (MBs), attraverso l’incorporazione di silice o Sep nel lattice di gomma naturale (emulsione in acqua di cis-1,4-poliisoprene), attraverso la flocculazione (aggregazione risultante dalla coesione di particelle di polimero) di una miscela acquosa di nanofiller a base silicea e gomma.
La tecnica di miscelazione in lattice ha dimostrato di favorire una omogenea dispersione di fibre di sepiolite idrofilica in matrice di gomma. La principali caratteristiche fisico-chimiche che controllano i processi di aggregazione in acqua come il pH, il potenziale Z, la concentrazione, assieme alle caratteristiche morfologiche del MB Sep-gomma naturale, sono state prese in considerazione allo scopo di investigare le interazioni Sep-gomma naturale. E’ stato proposto un meccanismo di flocculazione basato su attrazioni elettrostatiche e depletive, connesso all’elevato contenuto di filler (50% in peso) e alla peculiare anisotropia delle particelle di Sep.
Inoltre, i MBs sono stati utilizzati per preparare compositi sostenibili attraverso la combinazione di miscelazione in lattice e mescolazione meccanica. Questo approccio combinato sfrutta la buona distribuzione del filler e previene il rilascio di polveri durante il processo.
Una polimerizzazione Pickering in situ è stata considerata come alternativa per la produzione di nanocompositi eco-sostenibili. Particelle poliisoprene/filler a base silicea sono state sintetizzate sfruttando dell’effetto stabilizzante di filler inorganici che agiscono come tensioattivi riducendo la tensione superficiale e stabilizzando l’emulsione. Sulla base dei nostri risultati, viene suggerito un possibile meccanismo di polimerizzazione in emulsione stabilizzata da particelle solide.
In conclusione, l’approccio colloidale, basato su miscelazione in lattice e polimerizzazione Pickering in situ, può essere considerato un metodo sostenibile, semplice ed efficace adatto per applicazioni tecnologiche altamente performanti. I risultati indicano che le strategie utilizzate sono adatte per produrre nanocompositi altamente caricati di filler a base silicea.Sustainability has become a field of great interest in the world industry. For the scientific community the challenge lies in the identification of green synthetic approaches and new alternatives to petroleum-based materials. In the case of the tyre industry, the challenge is to identify possible design strategies and alternatives to reduce the environmental impact throughout the life cycle of tyres, by means of both the use of environmentally friendly materials and the development of innovative products, having reduced energy consumption and CO2 emissions. In this context, this PhD thesis is focused on the preparation of eco-friendly silica-based nanocomposites by using a colloidal approach to increase the dispersion of hydrophilic fillers in line with the new requirements of sustainability from the EU policies. The colloidal approach aims at compounding nanocomposites with hydrophilic fillers, whose efficient dispersion through traditional mixing still remains a challenging issue, due to their poor compatibility with the organic matrix. This technique aims at increasing the filler dispersion without any expensive surface modification, with the elimination of the volatile component released during mixing, producing significant benefits for environment and workers. Two different colloidal approaches were applied: i) latex compounding technique (LCT) and ii) in situ emulsion polymerization to prepare highly-loaded nanocomposite rubber materials containing silica-based fillers, silica and sepiolite (Sep) clay, considered a promising filler candidate for the polymer strengthening due to its fibrous structure and high particle aspect ratio (AR). The concentration, the charge and the shape of silica-based nanofillers were studied as relevant parameters on stabilization and destabilization of natural and synthetic polyisoprene latexes. An effective LCT procedure was established to produce eco-friendly composites, namely masterbaches (MBs), by incorporating silica or Sep into natural rubber latex (i.e. emulsion in water of cis-1,4-polyisoprene), through the flocculation (i.e. aggregation resulting from the bridging of polymer particles) of the silica-based nanofillers/rubber mixed aqueous system. LCT showed to favour a homogeneous dispersion of hydrophilic Sep fibers in the rubber matrix. The main physicochemical parameters which control aggregation processes in the aqueous medium, i.e. pH, -potential, concentration, as well as the morphological features of the final Sep-natural rubber MBs, were comprehensively investigated helping to figure out the Sep-NR interactions and to propose a flocculation mechanism, based on electrostatic and depletion attraction forces, remarkably connected both to the high content (50 wt.%) and to the peculiar anisotropy of Sep fibers. Furthermore, the MBs with high filler loadings were used to produce environmentally friendly composites, by combining LTC and melt mixing. This combined approach could take advantage of the good filler distribution and prevents dust from floating in the air during processing. In situ Pickering polymerization was considered as an alternative colloidal approach to produce eco-friendly nanocomposites. Polyisoprene/silica-based structured particles were synthesized on the base of the stabilizing effects of inorganic fillers which act like surfactants lowering the interfacial tension and stabilizing the emulsion. On the basis of our results, we suggested a possible mechanism for emulsion polymerizations stabilized by solid particles. In conclusion, the colloidal approach, based on both LTC and in situ Pickering emulsion polymerization, can be considered as green, simple and effective method suitable for high-performance technological applications. The outcomes indicate the suitability of the adopted strategies as a sustainable procedure for the production of high-loaded silica based-rubber nanocomposites.
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Wang, Hongzhi. « Understanding of charge effects in pickering emulsions and design of double pickering emulsion templated composite microcapsules ». Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52965.
Texte intégralRésumé :
Particle stabilized emulsions, also known as Pickering emulsions, have been widely used in many industry applications. While the breadth of potential applications for Pickering emulsions keeps growing, our fundamental understanding of Pickering emulsions is still poor. My thesis work addresses both fundamentals and applications of particle stabilized emulsions. In the fundamental part of this thesis work, we investigated the effects of particle charge on particle adsorption and the particle contact angle, and to investigate their ensuing consequences for the stability of Pickering emulsions. We provided the first experimental hint that the widely overlooked image charge repulsion can hinder the adsorption of particle to the oil-water interface and prevent the formation of Pickering emulsions. Consistently with the experimental suggestion, our theoretical model also confirmed that the image charge repulsion has the right order of magnitude, relative to the other forces acting on the particle, to impede particle adsorption and Pickering emulsification. For the conditions in which particle adsorption to the liquid interface does occur, the particle contact angle will play an important role in influencing the stability and type of Pickering emulsions. Our experimental work showed that the equilibrium contact angle of particles at interfaces and the type of emulsions preferentially stabilized by these particles can be strongly affected by the particles' charging state, which we attribute to a free energy contribution from the electric field set up by the charged particle and its asymmetric counterion cloud. A very simplistic calculation considering only the dipole field as the leading contribution and treating the water phase as a perfect conductor, found that the energy stored in the field is indeed strong enough and shows sufficient variation with the particle position to shift the equilibrium position significantly from where it would be based on interfacial tension alone. In a separate, more application oriented part of this thesis work, we have fabricated microcapsules from double Pickering emulsions and demonstrated that the combined use of hard silica particles and pH-responsive dissoluble polymer particles at the emulsion interface imparts a combination of pH-responsiveness (stimulated pore opening) and structural integrity to resulting capsules. We have further demonstrated the first double Pickering emulsion templated capsules in which interfacial polymerization was carried out at both emulsion interfaces, yielding a capsule with two composite shells, composed of polyurethane and silica particles, and characterized the transport of a model cargo through the capsules walls as well as the capsules' mechanical properties.
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Duffus, Laudina Jeneise. « Edible pickering emulsion technology : fabrication of edible particle stabilised double emulsions ». Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7456/.
Texte intégralRésumé :
Water-in-oil-in-water (W/O/W) double emulsion systems provide an innovative approach for the development of low-fat healthier foods. By replacing a proportion of the oil phase of a simple oil-in-water (O/W) emulsion with an internal water phase, the overall oil volume within the emulsion system can be decreased, with potentially negligible changes to its organoleptic properties. However, double emulsions are notoriously unstable for adequate periods of time, largely due to the existence of two oppositely curved water-oil (W/O) and oil-water (O/W) interfaces in close proximity. The present study investigates the use of Pickering stabilisation in order to enhance the stability of double emulsions. Pickering stabilisation mechanisms are reputed for superior, longer term stabilisation capacities when compared to conventional surfactant stabilised emulsions, but edible particles with Pickering functionality are scarce. The work in this thesis explores the impact of introducing Pickering stabilisation to a double emulsion structure, initially at only one of the two water/oil interfaces (either W/O or O/W) and ultimately across the entire interfacial areas. Initial work conducted centred on investigating the role of a range of edible particulates as potential Pickering stabilisers in simple emulsions (both W/O and O/W emulsion types). Based on the knowledge gained from these studies, a range of Pickering-Surfactant stabilised double emulsions (with particles or surfactant stabilising alternate interfaces), using a range of surfactants, and Pickering only stabilised double emulsion systems were prepared and analysed in terms of their microstructure, stability and encapsulation efficiencies.
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Jutz, Günther. « Mineralized bionanoparticle pickering emulsions ». kostenfrei, 2008. http://opus.ub.uni-bayreuth.de/volltexte/2009/508/.
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Faresin, Andrea. « Functional materials for Pickering emulsions ». Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3427313.
Texte intégralRésumé :
This doctoral thesis highlights the most interesting experimental results achieved between 2015 and 2018 by the author, during his stay in the laboratories of the Department of Chemical Sciences of the University of Padova. The fil rouge of this thesis work is Pickering Emulsions (PE); emulsions where solid particles alone are used as stabilizers instead of the typical molecular or macromolecular surfactants that are employed to produce widely used emulsions in pharmaceutics, drug delivery, cosmetics, food industry to name a few. Solid micro/nanoparticles accumulate at the interface between two immiscible liquids (typically denoted as oil and water phase) and stabilize droplets against coalescence. A great advantage of a PE is that it is relatively stable once made and that many solid particles can be endowed with useful characteristics: conductivity, responsiveness, porosity, catalysis and so on.
The chemical modification of silica nanoparticles (SiNP) and their use as PE stabilizers is the first theme treated in this thesis work. SiNP are functionalized with hydrophobic molecular structures for tuning their wettability, and with photo-active moieties to impart photocatalytic properties. In addition, silica-based PE are used to confine special ingredients needed for the colorimetric detection of acetone whose presence is associated to triacetone triperoxide, a deadly explosive used by terrorists in recent attacks, and for the development of a testing kit in the form of a pen.
Another interesting PE stabilizer is nanocrystalline cellulose (NCC). An extensive sperimentation was carried out to learn how to handle and to chemically functionalize NCC. This led to the development of robust protocols that allowed to install on cellulose nanocrystals a pH-sensitive dye and magnetic nanoparticles that were used to develop, as a proof of principle, a solid pH sensor for urea detection and a colorimetric/magnetic, doubly-responsive system. The modified NCC materials hold the potential as PE stabilizers whose study is underway.
The last part of the thesis reports the study, in collaboration with prof. S. Gross of the Chemical Sciences Department in Padova and prof. E. Hensen of the University of Eindhoven, for the production of ZnS nanoparticles through a controlled nucleation and crystallization under continuous flow conditions at room temperature, in water and without the use of any stabilizing ligand. The colloids display an average size of 5 nm and an impressively high specific surface area of 287 m2/g. Nanostructured ZnS is well known to be a direct wide-bandgap semiconductor and, for its tunable photophysical and electrochemical properties, is used for a broad range of applications ranging from catalysis and photocatalysis to nonlinear optics, optoelectronic devices and optical bioimaging. The possibility to prepare stable nanoparticles without the need of special ligand stabilization open the interesting perspective to use those as-prepared particles directly from the continuous flow reactor to stabilize functional PE. Work in this direction is currently underway.
Furthermore, a toolbox that was always available during this thesis work was flow chemistry, an ensemble of techniques for the manipulation of fluids on the micrometer scale. Such manipulation is carried out inside microchannels, confined environments whose geometries can be exploited to optimize unit operations – such as mixing and heat transfer – of profound interest for chemists. A flow chemistry approach was used to prepare ZnS nanoparticles and also to develop a selective bromination protocol of tetraphenyl porphyrins. This latter study, along with a study on the application of functionalized NCC as a flame retardant have been a unique opportunity to face interesting problems, although they were not related to the Pickering emulsions general theme of this thesis work.
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Brunier, Barthélémy. « Modeling of Pickering Emulsion Polymerization ». Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10320/document.
Texte intégralRésumé :
L’objectif du présent projet est de développer une méthodologie pour la modélisation fondamentale de procédés de polymérisation en émulsion sans tensioactif stabilisés par des particules inorganiques, dénommées "polymérisation en émulsion Pickering". La modélisation des systèmes de polymérisation en émulsion nécessite la modélisation de la distribution de taille des particules (PSD), qui est une propriété importante d'utilisation finale du latex. Cette PSD comprend des sous-modèles dédiés à la nucléation des particules, le transfert de masse entre les différentes phases (monomère, radicaux, stabilisant) et la coagulation des particules. Ces modèles devraient de préférence être validés expérimentalement de manière individuelle. La première partie principale du travail est consacrée à l'étude expérimentale. Cette partie peut être divisée en trois parties. La première partie décrit l'adsorption de particules inorganiques sur le polymère sans réaction. Une adsorption multicouche a été observée et l’isotherme B.E.T. a été capable de décrire cette adsorption. L'adsorption se révèle être plus importante pour une force ionique plus élevée. La dynamique d'adsorption semple être rapide et par conséquent le partage peut être considéré à l'équilibre pendant la polymérisation. La deuxième partie concerne l'étude de différents paramètres de réaction sur le nombre de particules et la vitesse de réaction dans des polymérisations ab initio. L'effet du mélange, de la concentration initiale des monomères et de la concentration de l'initiateur a été étudié. L'optimisation de ces conditions a été utile pour la partie de modélisation. La dernière partie décrit les différences entre plusieurs Laponite® à travers la polymérisation en émulsion ab initio du styrène.La deuxième partie principale du manuscrit a porté sur la modélisation de la polymérisation en émulsion Pickering. Le modèle de bilan de population et le nombre moyen de radicaux par particule ont été calculés en fonction de l'effet des particules organiques. La croissance des particules de polymère a été optimisée en ajustant les modèles d'entrée et de désorption des radicaux décrits dans la littérature aux données expérimentales. Aucune modification n'a été nécessaire, ce qui nous a permis de conclure que l'argile n'avait aucune influence sur l'échange radical. Cependant, la stabilisation joue un rôle important dans la production de particules de polymère. Le modèle de nucléation coagulante a été capable de décrire le taux de nucléation et de prédire le nombre total de particulesThe aim of the present project is to develop a methodology for fundamental modeling of surfactant-free emulsion polymerization processes stabilized by inorganic particles, referred to as “Pickering emulsion polymerization”. Modeling emulsion polymerization systems requires modeling the particle size distribution (PSD), which is an important end-use property of the latex. This PSD includes submodels dedicated to particle nucleation, mass transfer between the different phases (monomer, radicals, stabilizer), and particle coagulation. These models should preferably be individually identified and validated experimentally. The first main part of the work is dedicated to the experimental study. This part can be divided in three parts. The first part describes the adsorption of inorganic particles on polymer without reaction. Multilayer adsorption was observed and B.E.T. isotherm was able to describe this adsorption. The adsorption was found to be enhanced at higher ionic strength. The adsorption dynamics were found fast and therefore clay partitioning can be considered at equilibrium during polymerization. The second part concerned the investigation of different reaction parameters on the particles number and reaction rate in ab initio polymerizations. The effect of mixing, initial monomer concentration and initiator concentration were considered. Optimization of these conditions was useful for the modeling part. The last part described the differences between several LaponiteR_ grades through the ab initio emulsion polymerization of styrene. The second main part of the manuscript focused on the modeling of the Pickering emulsion polymerization. The population balance model and average number of radicals balance were adapted regarding the effect of inxi organic particles. The growth of the polymer particles was optimized by fitting the models of radicals’ entry and desorption described available in literature to the experimental data. No modification was needed, which allowed us to conclude that the clay had no influence on radical exchange. However, LaponiteR_ stabilization played an important role in polymer particles production. Coagulative nucleation model was able to describe the nucleation rate and predict the total number of particles
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Vílchez, Villalba Alejandro. « Polymeric Macroporous Nanocomposites using highly concentrated emulsions as templates ». Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/104576.
Texte intégralRésumé :
The design of nanocomposites, which typically consist of polymeric matrices with embedded particles having at least one characteristic length in the nanometer range, has recently been the focus of a great attention. Nanocomposites, in a large variety of morphologies and distinct compositions are already on the market. In this context, the construction of novel porous nanocomposites, exhibiting hierarchical structures, will allow the development of innovative advanced materials with promising applications in many fields: catalysis, gas/liquid storage, gas purification, etc.
The use of highly concentrated phase emulsions (HIPEs) as templates has been shown to be an effective route for the preparation of macroporous polymers. Specifically, the use of suitable surface-modified inorganic oxide nanoparticles as emulsions stabilizers (so called Pickering emulsions) provide an alternative approach to the classical surfactant-based systems, to obtain such hybrid organic-inorganic nanocomposite porous materials. Thanks to the ability of finely-divided solids to adsorb spontaneously at liquid-liquid interfaces, any functionality coming from the nanoparticles can be imparted to the materials, in a single-step preparation method.
It has been described that, the resulting macroporous nanocomposites, obtained in Pickering highly concentrated emulsions, typically exhibit closed-cell structures and rather large pore sizes. These drawbacks are frequently overcome by combining simultaneously surfactants and particles. Nevertheless, there is a lack of systematic study on how the interactions between these two emulsifiers influence the final physicochemical properties of the materials obtained. For instance, contrary to what is often expected, the addition of particles to a surfactant-stabilized emulsion or inversely, the addition of surfactant to a particle-stabilized emulsion can negatively influence its stability, rather than enhance it.
The main objective of this research work was to investigate the formation of polymeric macroporous nanocomposites with embedded functional nanoparticles, using W/O highly concentrated emulsions as templates. For this purpose, two kinds of nanoparticles with interesting functionalities have been used:
- Superparamagnetic iron oxide nanoparticles
- Titanium dioxide photocatalytic nanoparticles
Styrene and the crosslinker divinylbenzene are used in the emulsion continuous phase, as a model monomer system. The emulsions are processed into macroporous materials by free-radical polymerization of such a continuous phase. In all cases, nanoparticles are included in the systems, and three different types of emulsions are studied using different approaches:
(a) HIPEs stabilized with surfactants and prepared by the phase inversion method, containing nanoparticles inside the continuous phase.
(b) HIPEs stabilized with nanoparticles, in absence of surfactant and prepared by the drop-wise addition method. The use of Pickering emulsions to obtain nanocomposite materials constitutes a very novel approach, recently first described.
(c) HIPEs stabilized primary with nanoparticles with increasing amounts of surfactant molecules, prepared by the drop-wise addition method.
In this work, special emphasis has been given to the study of the individual contribution of either nanoparticles or surfactants on the (in)stability of the resultant highly concentrated emulsions. Moreover, the precise role that each emulsifier plays, focusing on their interactions and the related emulsion stabilization mechanisms, has been investigated.
In addition, we have study the arrangement of the nanoparticles in the resulting porous nanocomposites, with respect to several parameters such as particle size or surfactant concentration. Likewise, the main physical properties of the materials, such as macroporous structure, porosity, permeability or mechanical strength, have been compared.
Finally, the magnetic properties and photocatalytic activity of the nanocomposite materials, which contained iron oxide and titanium dioxide nanoparticles, respectively, have been characterized.La preparación de materiales constituidos por una matriz polimérica que contiene algún tipo de elemento inorgánico, como nanopartículas o nanotubos, ha generado durante los últimos años un enorme interés científico. Generalmente, estos materiales se denominan nanocompuestos. Actualmente, existen productos en el mercado en forma de sensores ópticos o productos en fase de desarrollo comercial, como poliolefinas reforzadas con arcilla en la industria automovilística. Uno de los campos de mayor actividad es la fabricación de materiales porosos avanzados, con aplicaciones en campos tan variados como el de membranas, purificación de gases o almacenamiento de líquidos/gases. Este trabajo de tesis tiene como objetivo principal el de obtener nanocomposites macroporosos con nanopartículas incorporadas, utilizando emulsiones altamente concentradas como plantilla. Para ello se han empleado emulsiones del tipo agua en aceite, estabilizadas tanto con tensioactivos como con nanopartículas (denominadas emulsiones de Pickering). La obtención de nanocompuestos macroporosos utilizando emulsiones de Pickering constituye un método novedoso descrito por primera vez recientemente. Con este propósito, se han utilizado dos tipos de nanopartículas funcionales: nanopartículas superparamagnéticas de óxido de hierro y nanopartículas fotocatalíticas de dióxido de titanio. Ambas han sido previamente funcionalizadas con ácido oleico para conferir hidrofobicidad a su superficie. Para obtener los materiales poliméricos, se ha llevado a cabo una polimerización entre el monómero estireno y el entrecruzante divinilbenceno en la fase externa de las emulsiones. De esta forma, se han obtenido materiales poliméricos porosos con nuevas funcionalidades magnéticas y fotocatalíticas. En primera instancia, se ha evaluado la interacción entre los dos emulsionantes empleados, nanopartículas y tensioactivos, y sus implicaciones en la estabilidad de las emulsiones altamente concentradas iniciales. Además, se ha estudiado la distribución de las nanopartículas en los materiales macroporosos obtenidos, en función de diversos parámetros como el tamaño o concentración de nanopartículas. Finalmente, se ha llevado a cabo una exhaustiva caracterización de las propiedades físicas de los materiales, tal como estructura macroporosa, porosidad, resistencia a la compresión o permeabilidad. También, se han estudiado las propiedades magnéticas y fotocatalíticas de los nanocompuestos, que contienen nanopartículas de óxido de hierro y de dióxido de titanio, respectivamente.
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French, David James. « Fundamental aspects of Pickering emulsion stabilisation ». Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20450.
Texte intégralRésumé :
Much research has been carried out in recent years on Pickering emulsions, but understanding of the underlying physics requires considerable strengthening. This thesis seeks to address several fundamental aspects by presenting the results of recent experimental work. This work has focused on a model oil-in-water emulsion system stabilised by fluorescent colloidal silica particles and using a mixture of dodecane and isopropyl myristate as the oil phase. The phase behaviour of the particle dispersions has been altered using sodium chloride and sodium iodide, whilst sodium hydroxide and hydrochloric acid have been used to adjust the pH of samples. Comparisons are also made to emulsions stabilised by commercially available fumed silica. Conventionally, it was assumed that a weakly flocculating particle dispersion is required in order to generate a stable Pickering emulsion. It is shown in this work, however, that in some circumstances a weakly flocculating dispersion leads to the least stable emulsion. It is therefore argued that a more nuanced view of Pickering stabilisation is required, taking into account the factors affecting whether particles will adsorb to the interface during emulsification. Very recently it has begun to be suspected that Pickering emulsions sometimes aggregate due to the sharing of particles between two droplets, an effect known as bridging. In this thesis it is also shown that particle bridges can form in Pickering emulsions at high shear, and that they can subsequently be broken by low shear or by modifying the particle wettability. For the first time, electron microscopy has been used to provide direct evidence of droplets sharing particles. A simple theoretical model is developed, based on collisions between partially coated droplets, which captures the trends observed experimentally. It is argued that particle bridging may have been overlooked in the literature, and that the shear history of emulsions is a crucial determinant of subsequent behaviour. The deaggregation of bridged emulsions has been studied using a novel method where two different colours of particles are used. By starting with two emulsions which are bridged, each stabilised by a different colour of particle, and then using confocal microscopy to study them as they are mixed together and deaggregate, the processes involved in deaggregation can be elucidated. These experiments have also shown, for the first time, the dynamic nature of particles in Pickering emulsions; particles transfer readily between droplets when the samples are placed on a roller bank. It is found that a period of unbridging and rebridging takes place prior to deaggregation of the emulsions, and the timescale of deaggregation can be tuned by varying the particle wettability. The two-colour method has also been applied to the study of Pickering emulsions which are repeatedly sheared. It is found that limited coalescence is not reestablished simply by re-applying the shear rate which was used in the initial emulsification. This behaviour is attributed to the presence of an elastic shell of particles at the interface, which inhibits droplet breakup, and is in contrast to that of surfactant-stabilised emulsions, where increasing the stabiliser concentration makes droplets more liable to deform and breakup. Finally, a short study has been carried out attempting to increase the scale of the experiments presented in this thesis to sample volumes of approximately one litre. This study has demonstrated the relevance of particle bridging to industrial emulsification processes. Overall, experiments with carefully controlled model Pickering emulsions, including those using two colours of particles, have revealed the fundamental workings of these arrested systems.
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Han, Chenhui. « Nanomaterials stabilized pickering emulsions and their applications in catalysis ». Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/134131/1/Chenhui%20Han%20Thesis_Redacted.pdf.
Texte intégralRésumé :
This thesis is an exploratory study of nanomaterials stabilized Pickering emulsions and their applications. The study illustrates some novel emulsion behaviour through dynamic observation and develops a mechanically switchable emulsion based on the microstructure design of nanomaterials. The droplets of emulsion are demonstrated as an effective microreactor for chemical reactions that happen at the oil-water interface, showing the potential application of Pickering emulsion in catalysis.
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Stiller, Sabine. « Pickering-Emulsionen auf Basis anorganischer UV-Filter ». [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=96938470X.
Texte intégralLivres sur le sujet "Emulsione Pickering"
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Pickering Emulsion and Derived Materials. MDPI, 2017. http://dx.doi.org/10.3390/books978-3-03842-353-9.
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Clay Minerals and Synthetic Analogous as Emulsifiers of Pickering Emulsions. Elsevier, 2022. http://dx.doi.org/10.1016/c2021-0-00096-1.
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Wypych, Fernando, et Rilton Alves de Freitas. Clay Minerals and Synthetic Analogous As Emulsifiers of Pickering Emulsions. Elsevier, 2022.
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Wypych, Fernando, et Rilton Alves de Freitas. Clay Minerals and Synthetic Analogous As Emulsifiers of Pickering Emulsions. Elsevier, 2022.
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Aveyard, Bob. Surfactants. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198828600.001.0001.
Texte intégralRésumé :
Characteristically, surfactants in aqueous solution adsorb at interfaces and form aggregates (micelles of various shapes and sizes, microemulsion droplets, and lyotropic liquid crystalline phases). This book is about the behaviour of surfactants in solution, at interfaces, and in colloidal dispersions. Adsorption at liquid/fluid and solid/liquid interfaces, and ways of characterizing the adsorbed surfactant films, are explained. Surfactant aggregation in systems containing only an aqueous phase and in systems with comparable volumes of water and nonpolar oil are each considered. In the latter case, the surfactant distribution between oil and water and the behaviour of the resulting Winsor systems are central to surfactant science and to an understanding of the formation of emulsions and microemulsions. Surfactant layers on particle or droplet surfaces can confer stability on dispersions including emulsions, foams, and particulate dispersions. The stability is dependent on the surface forces between droplet or particle surfaces and the way in which they change with particle separation. Surface forces are also implicated in wetting processes and thin liquid film formation and stability. The rheology of adsorbed films on liquids and of bulk colloidal dispersions is covered in two chapters. Like surfactant molecules, small solid particles can adsorb at liquid/fluid interfaces and the final two chapters focus on particle adsorption, the behaviour of adsorbed particle films and the stabilization of Pickering emulsions.
Chapitres de livres sur le sujet "Emulsione Pickering"
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Schröder, Anja, Meinou N. Corstens, Kacie K. H. Y. Ho, Karin Schroën et Claire C. Berton-Carabin. « Pickering Emulsions ». Dans Emulsion-based Systems for Delivery of Food Active Compounds, 29–67. Chichester, UK : John Wiley & Sons, Ltd, 2018. http://dx.doi.org/10.1002/9781119247159.ch2.
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Bon, Stefan A. F. « Pickering Emulsion Polymerization ». Dans Encyclopedia of Polymeric Nanomaterials, 1–6. Berlin, Heidelberg : Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-36199-9_264-1.
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Bon, Stefan A. F. « Pickering Emulsion Polymerization ». Dans Encyclopedia of Polymeric Nanomaterials, 1634–39. Berlin, Heidelberg : Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-29648-2_264.
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Destribats, Mathieu, Serge Ravaine, Valérie Heroguez, Fernando Leal-Calderon et Véronique Schmitt. « Outstanding Stability of Poorly-protected Pickering Emulsions ». Dans Trends in Colloid and Interface Science XXIII, 13–18. Berlin, Heidelberg : Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-13461-6_4.
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Lecomte-Nana, Giséle L., Volga Niknam, Anne Aimable, Marguerite Bieniab, David Kpogbemabou, Jean-Charles Robert-Arnouila et Asma Lajmi. « Microcapsules from Pickering Emulsions Stabilized by Clay Particles ». Dans Advances in Bioceramics and Porous Ceramics VIII, 107–24. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781119211624.ch10.
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Lan, Yang, Yankai Jia et Daeyeon Lee. « Chapter 10. Pickering Emulsions Stabilized by Polymer Colloids ». Dans Soft Matter Series, 323–48. Cambridge : Royal Society of Chemistry, 2019. http://dx.doi.org/10.1039/9781788016476-00323.
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Shah, Bakht Ramin. « Stability and Release Behavior of Bioactive Compounds (with Antioxidant Activity) Encapsulated by Pickering Emulsion ». Dans Emulsion‐based Encapsulation of Antioxidants, 287–309. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-62052-3_8.
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Chevalier, Yves, Marie-Alexandrine Bolzinger et Stéphanie Briançon. « Pickering Emulsions for Controlled Drug Delivery to the Skin ». Dans Percutaneous Penetration Enhancers Chemical Methods in Penetration Enhancement, 267–81. Berlin, Heidelberg : Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-45013-0_19.
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Zhu, He, Lei Lei, Bo-Geng Li et Shiping Zhu. « Development of Novel Materials from Polymerization of Pickering Emulsion Templates ». Dans Polymer Reaction Engineering of Dispersed Systems, 101–19. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/12_2017_15.
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Wang, F., Y. Zhu, W. Wang et A. Wang. « Preparation of Macroporous Adsorbent Based on Montmorillonite Stabilized Pickering Medium Internal Phase Emulsions ». Dans Springer Proceedings in Earth and Environmental Sciences, 436–39. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22974-0_106.
Texte intégralActes de conférences sur le sujet "Emulsione Pickering"
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Berton-Carabin, Claire. « Lipid oxidation in Pickering emulsions ». Dans 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/nfxb4600.
Texte intégralRésumé :
Pickering emulsions have garnered great interest in food science lately. These systems are characterized by the use of colloidal particles as physical stabilizers, that strongly anchor at the oil-water interface, instead of conventional emulsifiers. Many biobased particles have recently been identified as useful for this application, which holds potential for revolutionizing the field of food emulsion formulation [1,2]. However, although the potential in terms of physical stabilization of oil-in-water (O/W) emulsions has been thoroughly explored in the past years, how such emulsions may resist lipid oxidation, and whether particles could also be used to protect labile polyunsaturated lipids against oxidation is still questionable. This presentation aims at shedding light on this question by combining a review of the different types of food-compatible particles that have been recognized as useful to form Pickering emulsions, discussing examples of mitigation of lipid oxidation in such emulsions [3,4], and finally reflecting on the desired properties and possible targeted design of particles to achieve dual physical and oxidative stabilization of emulsions [5].[1] Berton-Carabin, C., & Schroën, K. (2015). Pickering emulsions for food applications: Background, trends and challenges. Ann. Rev. Food Sci. Technol., 6, 263–297.[2] Dickinson, E. (2020). Advances in food emulsions and foams: Reflections on research in the neo-Pickering era. Curr. Opin. Food Sci., 33, 52–60.[3] Schröder, A., Laguerre, M., Sprakel, J., Schroën, K., & Berton-Carabin, C. (2020). Pickering particles as interfacial reservoirs of antioxidants. J. Colloid Interface Sci., 575, 489–498.[4] Schröder, A., Laguerre, M., Tenon, M., Schroën, K., & Berton-Carabin, C. (2021). Natural particles can armor emulsions against lipid oxidation and coalescence. Food Chem., 347, 129003.[5] Berton-Carabin, C., Schröder, A., Schroën, K., & Laguerre, M. (2021). Lipid oxidation in Pickering emulsions. In Garcia-Moreno, P., Jacobsen, C., Sorensen, A. D., & Yesiltas, B. (Eds), Omega-3 Delivery Systems, Elsevier, Cambridge, MA., pp. 275-293.
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Uluata, Sibel, Seymanur Avci et Gokhan Durmaz. « Comparing Physical Stability of Ultrasound and Pickering Emulsion Fortified with Vitamin D ». Dans 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/cwoy2387.
Texte intégralRésumé :
"Vitamin D is one of the important fat-soluble vitamins for human health. The fact that this vitamin is much lower or higher than needed creates some problems. The World Health Organization (WHO) has recognized fortification as the most effective and safest method to meet the daily requirements of Vitamin D, addressing malnutrition. However, it has numerous difficulties such as loss during processing and storage during food fortification. In recent developments in nanotechnology, microencapsulation technique such as emulsion has great potential to design efficient nanomaterials with desired functionality for fortifying potentiators such as vitamin D. In this study, the effect of emulsifier type and different oil types on the formation and stability of emulsions was determined by measuring the changes in droplet properties (size and charge) under pH, salt and temperature conditions. Emulsion fortified with vitamin D was prepare by using oil phase (linseed, sunflower and MCT oil), emulsifier (pea and lentil protein) with ultrasonication and pickering emulsion method. The mean particle diameter of the pea protein-linseed oil-water emulsions formed using the ultrasonication method was 0.21 µm and the droplet charge was -37.3 mV. In the Pickering emulsion method, the mean particle diameter was 0.17 µm and the droplet charge was -26.75 mV. Also, particle size were 0.24, 22.14, 0.15 µm and particle charge were 24.60, -19.65, -27.80 mV at pH 3, 5 and 7, respectively. In addition, the particle size of pickering emulsion did not dramtically change at 30˚C and 90˚C temperatures and at 100 mM and 500 mM salt concentrations. As a result, pickering emulsion was physically more stable than ultrasound emulsion. This study was supported by Inonu University Scientific Research Projects Unit with The Project number :FYL-2021-2355"
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Hatchell, Daniel, Wen Song et Hugh Daigle. « Effect of Inter-Particle Van Der Waals Attraction on the Stability of Pickering Emulsions in Brine ». Dans SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206112-ms.
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Abstract Pickering emulsions are stabilized by solid particles that occupy the fluid-fluid interface, physically preventing coalescence. Their stability in brine, where interparticle electrostatic repulsion is negligible and van der Waals (vdW) attraction dominates, makes them attractive for applications in porous media. Recent studies postulate that inter-droplet particle networks assemble in brine and aid Pickering emulsion stability to coalescence. This work experimentally assesses the effect of increasing interparticle vdW attraction on particle network strength and emulsion stability. We grafted 6 nm, 12 nm, and 20 nm silica nanoparticles with varying densities of polyethylene glycol (PEG) to prevent aggregation and dispersed them in either brine or deionized water (DI). We characterized the PEG-coated nanoparticles with thermogravimetric analysis and dynamic light scattering to determine PEG grafting density, diameter, and zeta potential. To generate oil-in-water emulsions, we sonicated dispersions of variable nanoparticle concentration and decane in equal volumes. We imaged the emulsions with microscopy and centrifuged them for 15 minutes at 5000 g of acceleration, using the volume of decane released after centrifugation as a measurement of emulsion coalescence to the applied force. Nanoparticle characterization confirmed successful grafting of PEG to the silica surface. We compared trends in emulsion stability as a function of salinity and particle diameter to changes in the relevant interparticle forces described by extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Analysis of microscopy images showed an increase in emulsion droplet diameter with decreasing nanoparticle concentration, salinity, and increasing nanoparticle diameter. Through centrifugation we observed that lower PEG grafting densities tended to produce more stable emulsions, suggesting that particles with high grafting densities and consequently high steric repulsion tended to repel and prevent formation of strong particle networks. Emulsions generated in DI coalesced more easily, indicating that electrostatic repulsion dominated relative to vdW attraction and that particle networks did not form. In brine, where electrostatic forces were screened out by counterions, the emulsions better resisted coalescence, consistent with the formation of a particle network. The strength of the network was inferred from the difference in emulsion stability to coalescence in DI and in brine. We measured a greater brine-DI stability difference of 3.7× for the larger 20 nm PEG-coated nanoparticles, compared with 3.3× and 2.2× for the 12 nm and 6 nm PEG-coated particles, respectively, further supporting the role of particle networks on emulsion stability.
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Zhu, Youyi, Peng Yu et Jian Fan. « Study on Nanoparticle Stabilized Emulsions for Chemical Flooding Enhanced Oil Recovery ». Dans International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21456-ms.
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Abstract Chemical flooding is one of enhanced oil recovery (EOR) methods. The primary mechanism of EOR of chemical flooding is interfacial tension reduction, mobility ratio improvement and wettability changes. Recent studies showed that enhancing emulsification performance was beneficial to improve oil displacement efficiency. The formation of Pickering emulsion by nanoparticles could greatly improve the emulsifying performance. Using nanoparticles stabilized emulsions for chemical EOR application is a novel method. In this study, six different types of nanoparticles were selected, including hydrophilic nano silica, modified nano silica, carbon nanotubes and bentonite, etc. The nanoparticle combine with petroleum sulfonate could form a stable emulsion. Particle wettability were measured by using contact angle measurement (OCA20). Emulsifying intensity index was measured for different nanoparticle-stabilized emulsions. The mechanisms of nanoparticle-stabilized emulsions and relationship between emulsion stability have been investigated. The influence of dispersant on nanoparticle-stabilized emulsions also has been investigated. Nanoparticles mainly play a role in improving the stability of emulsions while surfactant play a major role in enhancing the emulsifying dispersion. The wettability of solid particles was one of the most important factors that affects the stability of emulsions. Partial hydrophobic nanoparticles were much easier to form stable emulsions than hydrophilic nanoparticles. Nanoparticles could form a three-dimensional network structure, thereby the stability of the emulsion was improved. Use of surfactant to disperse nanoparticles could further improve the emulsion stability. Finally, three nanoparticles stabilized emulsion formulations were developed for chemical flooding EOR. Nanoparticle-stabilized emulsions could improve oil displacement efficiency in chemical combination flooding. This research was used to optimize chemical combination flooding formulation and has a guidance function for application of nanoparticles in chemical flooding EOR.
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Chu, Yifu, et Lingyun Chen. « The effect of uniform whey protein microgels on oil-in-water emulsion property improvements and their potential application as fat replacers to prepare fat-reduced food products ». Dans 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/txeh2871.
Texte intégralRésumé :
Protein-based microgels have the potential to mimic the oral lubrication properties of fat droplets at the fat-oral surface. As food proteins contribute to only 4 kcal per gram with high satiation, protein microgels are highly expected to be used as fat substitutes to develop novel low-calorie food, as a strategy against obesity prevalent. In our lab, we developed a facile method to fabricate uniform whey protein microgel with controllable size by modulating the protein-polysaccharide interactions. The microgel system (containing microgels, polysaccharides and unconcerted protein molecules) can stabilize oil-in-water emulsion with long-term stability and strong texture. The individual contributions of microgel, protein and polysaccharide will be discussed and the microgels can work both at the interface and in the bulk phase to improve the emulsion properties. Without any molecule surfactants such as protein molecules, the microgel alone can serve as an efficient Pickering stabilizer that can form oil-in-water Pickering emulsion with long-term stability and strong elasticity through strong hydrophobic interactions. When the interfacial layer is dominated by protein molecules, the microgels are dispersed in the bulk phase and the jamming effect brought by the microgels between the oil droplets effectively prevents flocculation and coalescence and strengthens the emulsion textures. This effect can make 30% oil emulsions show similar rheological and flow behavior to emulsions containing 50% oil. These results demonstrate that the protein microgel system has the potential for food applications in preparing €œlow fat€ emulsion-based food formulations with a comparable texture to that of full-fat counterparts.
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Tsabet, Emir, Shad Seddiqui et Louis Fradette. « Pickering Emulsions Generation : Drop Stabilization Rate ». Dans 14th Asia Pacific Confederation of Chemical Engineering Congress. Singapore : Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-1445-1_268.
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Ziqian, Li, Oliver Bogojevic et Zheng Guo. « Oxidative Depolymerized Nanocelluloses for Pickering Emulsion ». Dans Virtual 2021 AOCS Annual Meeting & Expo. American Oil Chemists’ Society (AOCS), 2021. http://dx.doi.org/10.21748/am21.525.
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Gavrielatos, Ilias, Ram S. Mohan et Ovadia Shoham. « Separation of Oil and Water Emulsions : Is Heating Good Enough ? » Dans SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210004-ms.
Texte intégralRésumé :
Abstract Surfactants and nanoparticles (NP) frequently act as stabilizers for oil and water emulsions. There is a need to investigate whether such NP stabilized emulsions (also known as Pickering emulsions) require different treatment for break-up, as compared to the well-known method to separate surfactant stabilized emulsions, i.e., heating. Thus, the main objectives of this work were to identify emulsions resistant to heating and develop a process able to accelerate the separation kinetics of such ultra-tight emulsions. Extensive experimental investigations on the stability of different types of oil and water emulsions under various temperature and brine salinity conditions were carried out using a state-of-the-art Portable Dispersion Characterization Rig (P-DCR). The batch separator was equipped with a high-resolution, surveillance camera to monitor emulsion separation kinetics. Commercial grade mineral oil and synthesized brines with various salinities were used as the test fluids. Silica nanoparticles of different wettability and surfactants with different HLB values were deployed as the stabilizing agents for the produced emulsions. It was found that the elevated temperature effects dominate the separation kinetics of the studied emulsions, as compared to any brine salinity effects, especially at higher temperatures, namely, 60°C and 80°C. Moreover, the effects of high temperatures and brine salinities on the separation kinetics were much more significant for the emulsions stabilized by surfactants than for NP stabilized emulsions. Perhaps more importantly, neither high temperature nor high brine salinity had any remarkable effects on the separation kinetics of the emulsions stabilized by hydrophobic NP. It was also shown that the hydrophobic NP dominate the stability mechanism for dual emulsifier fluid systems, such as emulsions stabilized by both hydrophobic NP (R974) and a surfactant of low HLB value (Span 80). A novel oil-water emulsion break-up process was developed to enhance the kinetics of the separation, irrespective of the underlying emulsion stability mechanisms, namely, surfactant, NP or both. The performance of this separation process was superior to heating, which is the conventional method applied to separate oil-field emulsions. Finally, it is envisioned that the newly developed process may be applied in the field as an in-line separation system for tight oil-field emulsions.
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Wang, Zhenjie, Tayfun Babadagli et Nobuo Maeda. « Can We Generate Stable Pickering Emulsions Activating Naturally Occurring Nanoparticles in the Reservoir for Cost Effective Heavy-Oil Recovery ? » Dans SPE Western Regional Meeting. SPE, 2021. http://dx.doi.org/10.2118/200880-ms.
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Abstract Activating naturally occurring nanoparticles in the reservoir (clays) to generate Pickering emulsions results in low-cost heavy oil recovery. In this study, we test the stability of emulsions generated using different types of clays and perform a parametric analysis on salinity, pH, water to oil ratio (WOR), and particle concentration; additionally, we report on a formulation of injected water used to activate the clays found in sandstones to improve oil recovery. First, oil-in-water (O/W) emulsions generated by different clay particles (bentonite and kaolinite) were prepared for both bottle tests and zeta potential measurements, then the stability of dispersion was measured under various conditions (pH and salinity). Heavy crude oils (50 to 170,000 cP) were used for all experiments. The application conditions for these clay types on emulsion generation and stability were examined. Second, sandpacks with known amounts of clays were saturated with heavy-oil samples. Aqueous solutions with various salinity and pH were injected into the oil-saturated sandpack with a pump. The recoveries were monitored while analyzing the produced samples; a systematic comparison of emulsions formed under various conditions (e.g., salinity, pH, WOR, clay type) was presented. Third, glass bead micromodels with known amounts of clays were also prepared to visualize the in-situ behavior of clay particles under various salinity conditions. The transparent mineral oil instead of opaque heavy oil was used in these micromodel tests for better visualization results. Recommendations were made for the most suitable strategies to enhance heavy oil recovery with and without the presence of clay in the porous medium; moreover, conditions and optimal formulations for said recommendations were presented. The bottle tests showed that 3% bentonite can stabilize O/W emulsions under a high WOR (9:1) condition. The addition of 0.04% of NaOH (pH=12) further improved the emulsion stability against salinity. This improvement is because of the activation of natural surfactant in the heavy oil by the added alkali—as confirmed by the minimum interfacial tension (0.17 mN/M) between the oil and 0.04% of the NaOH solution. The sandpack flood experiments showed an improved sweep efficiency caused by the swelling of bentonite when injecting low salinity fluid (e.g., DIW). The micromodel tests showed a wettability change to be more oil-wet under high salinity conditions, and the swelling of bentonite would divert incoming water flow to other unswept areas thus improving sweep efficiency. This paper presents new ideas and recommendations for further research as well as practical applications to generate stable emulsions for improved waterflooding as a cost-effective approach. It was shown that select clays in the reservoir can be activated to act as nanoparticles, but making them generate stable (Pickering) emulsions in-situ to improve heavy-oil recovery requires further consideration.
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Wang, Yixiang, Bin Li, Shilin Liu, Xiaogang Luo, Xingzhong Zhang et Yan Li. « Pickering emulsions stabilized by soybean protein isolate/cellulose nanofibrils : Influence of pH ». Dans 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/zksv4215.
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Emulsions including Pickering emulsions and nanoemulsions have enormous application potential for inhibiting lipid oxidation. Polysaccharides like κ-carrageenan can improve the gel-like behavior of protein-stabilized Pickering emulsions. Tea water-insoluble proteins and κ-carrageenan can be used for preparing fish oil-in-water Pickering emulsions and fish oil gels. The characteristics of Pickering emulsions and fish oil gels at different proportion of tea water-insoluble proteins and κ-carrageenan were analyzed by high-speed homogenization assisted with ultrasonic treatment. The physicochemical analysis and secondary structure of mixtures showed that the turbidity reduced, particle size unchanged except that of mixtures at 80:20 and zeta potential was unaltered with the addition of κ-carrageenan; meanwhile, the secondary structure of mixtures changed due to the addition of κ-carrageenan. The viscoelastic behavior enhanced compared with that stabilized by tea water-insoluble proteins only. Fish oil gels using mixture-stabilized PEs as a template had a solid-like behavior with a storage modulus of approximately 200 kPa. Besides, the effects of tocopherol nanoemulsions on lipid oxidation of fish sausages were assessed during 16-day storage at 4 °C. Nanoemulsions including 250 and 500 mg/kg tocopherol improved fish sausages’ quality during cold storage and effectively inhibited lipid oxidation due to low peroxide value and high polyunsaturated fatty acid content. The droplet diameter of nanoemulsions including tocopherol stored at 4 °C for 16 days was below 500 nm. The small droplets with even distribution, and high stability of tocopherol nanoemulsions might explain the potential mechanism of inhibiting lipid oxidation in fish sausages. Interestingly, nanoemulsions encapsulated with 250 mg/kg tocopherol were effective to delay the lipid oxidation and improve fish sausages quality during cold storage. These findings will be useful for developing new edible hydrocolloid systems such as Pickering emulsions and nanoemulsions to inhibit lipid oxidation in aquatic products and broaden the application of emulsions in food industry.