Дисертації з теми "Growth and self assembly"
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Cruz, Daniel Alejandro. "Hierarchical Self-Assembly and Substitution Rules." Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7770.
Повний текст джерелаMolnar, G., L. Dozsa, Z. Vertesy, and Z. J. Horvath. "Thickness Dependent Growth of Epitaxial Iron Silicide Nanoobjects on Si (001)." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35180.
Повний текст джерелаJiang, Feng. "Ligand Controlled Growth of Aqueous II-VI Semiconductor Nanoparticles and Their Self-Assembly." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311311.
Повний текст джерелаBouville, Florian. "Self-assembly of anisotropic particles driven by ice growth : Mechanisms, applications and bioinspiration." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0155/document.
Повний текст джерелаSelf-assembly phenomena are of prime interest in materials science, because they fill the gap between assembly of macrostructure and processing of nanomaterials. Self-assembly is based on the spontaneous organization of individual small constituents into patterns and structures. Controlling the spatial arrangement can possibly improve materials properties by maximizing its response in a given direction. Furthermore, particular types of spatial arrangement, such as found in natural structures, can even induce new properties. During the past three years, we have used ice templating process to trigger the assembly of platelet-shaped particles to replicate the hierarchical structure of nacre. Control over this technique allowed structural customization at different length-scales: local orientation of the platelets, ice crystal long range order, and the control if the interfaces between the platelets. This hierarchical process has set the ground for the creation of a new fully mineral nacre-like alumina. The local platelet self-assembly triggered by ice growth was investigated by Discrete Element Modelling which provided new insight into the dynamic phenomenon responsible for the particles alignment. Synchrotron X-ray tomography was used to validated the model results. The different architecture observed in the final samples are not the result of a percolation threshold, as one could expect, but is instead a consequence of the delicate balance between pushing and engulfment at the solidification front. The local alignment of platelets can be beneficial for the functional and structural characteristics of composites and relevant aspects for two potential applications were investigated: the thermal properties of the hexagonal boron nitride/silicon rubber composites and the mechanical properties of macroporous alumina. Further adaptation of the process allowed for long range ordering of the ice crystals (up to the centimeter scale). Different tools have also been developed in order to characterize the response of composites as a function of the architecture at the level of the macropores and particle organisation. Once those two levels of alignment were achieved, the addition of a glassy phase and nanoparticles to the grain boundaries of the platelets introduces, just like in nacre, interfaces capable of deflect and even stopping crack propagation
Hille, Pascal [Verfasser]. "Advanced group III-nitride nanowire heterostructures - self-assembly and position-controlled growth / Pascal Hille." Gießen : Universitätsbibliothek, 2017. http://d-nb.info/1132510511/34.
Повний текст джерелаNardi, Elena. "Growth of organic nanostructures through on-surface reactions : from phthalocyanines self-assembly to polymeric phthalocyanines." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4351/document.
Повний текст джерелаSurface-assisted covalent coupling of suitably designed molecular precursors on metal surfaces has recently emerged as a new route towards the design of novel molecular architectures promising for future applications. Phthalocyanines and their derivatives have been widely studied for their chemical and optoelectronic properties. In this thesis the synthesis of phthalocyanine compounds is presented. The compounds are obtained through an on-surface reaction between tetracarbonitrile-functionalized precursors and metals. The experimental investigation is carried out by means of scanning tunnelling microscopy and X-Ray photoemission spectroscopy. Two molecular precursors, TCN-DBTTF and PPCN, are studied. TCN-DBTTF molecules are deposited with metal atoms (Mn, Fe, or Cu) on Ag(111) and Au(111). Annealing is used to activate the reaction of cyclotetramerization between precursors and metals. In the most favourable case (TCN-DBTTF with Fe on Ag(111)) the reaction can be activated at 200°C and leads to the synthesis of individual phthalocyanines. Increasing the temperature allows the synthesis of polymeric lines, at 250°C, and small 2D domains, at 275°C. Similar results are obtained for PPCN deposition with Mn or Cu on Au(111). In this latter case, the evolution of core level spectra allows a chemical proof of the on-surface reaction. The factors affecting on-surface cyclotetramerization have also been studied. This study demonstrates the versatility of the method: on-surface cyclotetramerization allows creating original 2D polymers connected by phthalocyanine macrocycles, and may work with a wide range of tetracarbonitrile-functionalized precursors and metallic atoms
Davey, Roger J. "The nucleation and growth of crystals from solution - molecular self assembly, materials science and process technology." Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525976.
Повний текст джерелаDahal, Yuba Raj. "Equilibrium and kinetic factors in protein crystal growth." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/36220.
Повний текст джерелаDepartment of Physics
Jeremy D. Schmit
Diseases such as Alzheimer’s, Parkinson’s, eye lens cataracts, and Type 2 diabetes are the results of protein aggregation. Protein aggregation is also a problem in pharmaceutical industry for designing protein based drugs for long term stability. Disordered states such as precipitates and gels and ordered states such as crystals, micro tubules and capsids are both possible outcomes of protein–protein interaction. To understand the outcomes of protein–protein interaction and to find the ways to control forces, it is required to study both kinetic and equilibrium factors in protein–protein interactions. Salting in/salting out and Hofmeister effects are familiar terminologies used in protein science field from more than a century to represent the effects of salt on protein solubility, but they are yet to be understood theoretically. Here, we build a theory accounting both attractive and repulsive electrostatic interactions via the Poisson Boltzmann equation, ion–protein binding via grand cannonical partition function and implicit ion–water interaction using hydrated ion size, for describing salting in/salting out phenomena and Hofmeister and/or salt specific effect. Our model free energy includes Coulomb energy, salt entropy and ion–protein binding free energy. We find that the salting in behavior seen at low salt concentration near the isoelectric point of the protein is the output of Coulomb energy such that the addition of salt not only screens dipole attraction but also it enhances the monopole repulsion due to anion binding. The salting out behavior appearing after salting in at high salt concentration is due to a salt mediated depletion interaction. We also find that the salting out seen far from the isoelectric point of the protein is dominated by the salt entropy term. At low salt, the dominant effect comes from the entropic cost of confining ions within the aggregates and at high salt, the dominant effect comes from the entropy gain by ions in solution by enhancing the depletion attraction. The ion size has significant effects on the entropic term which leads to the salt specificity in the protein solubility. Crystal growth of anisotropic and fragile molecules such as proteins is a challenging task because kinetics search for a molecule having the correct binding state from a large ensemble of molecules. In the search process, crystal growth might suffer from a kinetic trap called self–poisoning. Here, we use Monte Carlo simulation to show why protein crystallization is vulnerable to the poisoning and how one can avoid such trap or recover crystal growth from such trap during crystallization. We show that self–poisoning requires only three minimal ingredients and these are related to the binding affinity of a protein molecule and its probability of occurrence. If a molecule attaches to the crystal in the crystallographic state then its binding energy will be high but in protein system this happens with very low probability (≈ 10−5). On the other hand, non–crystallographic binding is energetically weak, but it is highly probable to happen. If these things are realized, then it will not be surprising to encounter with self–poisoning during protein crystallization. The only way to recover or avoid poisoning is to alter the solution condition slightly such as by changing temperature or salt concentration or protein concentration etc.
Farrer, I. "Growth and applications of self-assembled quantum dots." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598945.
Повний текст джерелаYoshikawa, Taro [Verfasser], and Oliver [Akademischer Betreuer] Ambacher. "Toward ultra-thin nanocrystalline diamond film growth: electrostatic self-assembly of non-aggregated diamond nanoparticles onto substrate surfaces." Freiburg : Universität, 2017. http://d-nb.info/115294469X/34.
Повний текст джерелаBartels, Martin. "Self-assembled epitaxial growth of CdSe quantum dot structures." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=971575142.
Повний текст джерелаMohaddes, Ardabili Ladan. "Growth and characterization of self-assembled ferromagnetic iron nanowires." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3432.
Повний текст джерелаThesis research directed by: Material Science and Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Riel, Bruno J. "Mechanisms governing the growth of self-assembled quantum dots." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6448.
Повний текст джерелаJoyce, Peter Brian. "Controlled growth of InAS/GaAs self-assembled quantum dots." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405028.
Повний текст джерелаMukherjee, Sanjoy. "Synthesis, Characterization, and Growth Mechanism of Single-Walled Metal Oxide Nanotubes." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16176.
Повний текст джерелаChen, Jing. "Novel H-bond donor polymers for layer-by-layer self-assembly multilayered films." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0087/document.
Повний текст джерелаThis work deals with the design of novel hydrogen-bond donor polymers and their use as partner in new tailor-made multilayered films prepared by the layer-by-layer (LbL) process. In this context, a novel regioselective and chemoselective “click-type” reaction of unprotected mercaptoalcohols onto poly(2,3,4,5,6-pentafluoro-styrene) (PPFS) has been developed, and applied to the synthesis of new hydroxylated H-bond donor polymers. This coupling with heterofunctional thiol is used to prepare a library of polymers differing in the degree of substitution (DS) and/or functionality. The fine control of these parameters makes it possible to tune their interaction ability with various acceptor polymers such as poly(4-vinyl pyridine) (P4VP), poly(n-butyl acrylate) (PBA) and poly(ethylene oxide) (PEO), such that all possible scenarios (immiscible blend, partially or totally miscible blend or interpolymer complex) can be achieved. Subsequently, the resulting H-bond donor polymers (PPFS derivatives) were used to successfully build-up multilayered films with using P4VP as partner via layer-by-layer (LbL) through the dip deposition process. The influence of various parameters related to structure of the partners (DS, nature of the PPFS derivatives), the chemical structure of the surface onto which the film is built-up (self-assembled monolayer vs. polymer brush) and the deposition process (concentration of deposition solutions, nature of the first deposited partner) was in-depth evaluated, on both the growth mechanism and on the surface features of the multilayered films
Jones, Aleksy K. "Kinetically determined surface morphology in epitaxial growth." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2499.
Повний текст джерелаKleppmann, Nicola [Verfasser], Sabine [Akademischer Betreuer] Klapp, and Andreas [Akademischer Betreuer] Heuer. "Simulation of growth and self-assembly of complex molecules on surfaces / Nicola Kleppmann. Gutachter: Andreas Heuer ; Sabine Klapp. Betreuer: Sabine Klapp." Berlin : Technische Universität Berlin, 2015. http://d-nb.info/1077040156/34.
Повний текст джерелаPham, Son Tung. "Epitaxial growth and magnetic properties of self-assembled GeMn quantum dots." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0504.
Повний текст джерелаIn the frame of this thesis work, we have investigated the growth of self-assembled GeMn quantum dots on Si substrates by means of Molecular Beam Epitaxy. The doping Mn concentration ranges from 2 up to 8%. We have found that the lowest temperature at which the formation of self-assembled quantum dots is still preserved is about 400 °C.We have thus performed the growth of GeMn quantum dots at 410 and 430 °C. By combining numerous characterization techniques to investigate the quantum-dot properties, including structural properties (TEM), surface morphology (RHEED, AFM), magnetic properties (SQUID, XMCD) and composition (EDX), we have determined the key parameters allowing to control the magnetic properties of GeMn quantum dots. Of particular interest, we have demonstrated that well-controlled GeMn quantum dots can exhibit a Curie temperature up to 380K.The second part of this thesis work deals with the growth of GeMn quantum dots in multilayered structures. Interestingly, we have observed that the dots in upper lays can grow on the top of the buried dots, leading to a vertical ordering of dots along the growth direction. We also shown that the decrease of the wetting layer thickness in the upper layers of a multilayered structure is the main parameter that leads to the increase of the dot size and height. Such an evolution of the wetting layer thickness can be explained by an accumulation of elastic strain in the Si spacer layers induced by the lower Ge wetting layers. This finding opens the route to the realization of a multilayer structure in which the islands have equal size in all layers
Kamarudin, Mazliana Ahmad. "Growth and optical properties of self-assembled GaSb/GaAs quantum dots." Thesis, Lancaster University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547945.
Повний текст джерелаBierwagen, Oliver. "Growth and anisotropic transport properties of self assembled InAs nanostructures in InP." Doctoral thesis, [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985352930.
Повний текст джерелаCapacci-Daniel, Christina Anne. "Crystal growth of polymorphic bis-diphenyl ureas on self-assembled monolayer templates." Connect to Electronic Thesis (CONTENTdm), 2009. http://worldcat.org/oclc/463440944/viewonline.
Повний текст джерелаJohnson, Tamina L. "Elastin-Like Polypeptide Fusion Tag as a Protein-Dependent Solubility Enhancer of Cysteine-Knot Growth Factors." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7629.
Повний текст джерелаSummerfield, Alex. "Studies of self-assembled metal-organic nanostructures and the MBE growth of graphene." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33067/.
Повний текст джерелаDaher, Mansour Michel. "Transition metal nanolines on a nanopatterned silver substrate : self-organized growth and magnetic properties." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0287.
Повний текст джерелаInterest in the magnetic properties of low dimensional transition metal and lanthanide nanostructures has seen an unprecedented rise in the last two decades due to both their fundamental interest and perspectives of technological applications. Remarkably, the magnetic properties of nanostructures can be tuned by controlling their geometry, atomic structure and chemical environments. In this thesis, a one-dimensional template composed of self-organized Si nanoribbons is used to grow transition metal nanolines, prior to the characterization of their magnetic properties. The geometries and the atomic structure of both the Si nanoribbons and the metal nanolines were investigated in situ by scanning tunneling microscopy. The growth mechanisms were investigated by exploring a large set of growth conditions. Regarding the Si growth, our study shows that a temperature of 490 K is necessary to obtain a long-range ordered one-dimensional template. Concerning the transition metal study, the results resolved the nanoline geometries and atomic structures.To access the magnetic properties of the Co nanolines on Si, XMCD measurements were performed using different magnetic field orientations and temperatures.The results show that the first two Co layers directly adsorbed onto the Si nanoribbons present a weak magnetic response while the upper Co layers exhibit an enhanced magnetization. Remarkably, two in-plane easy axes of magnetization were evidenced.The magnetic moments and the magnetic anisotropic energy are determined quantitatively.Temperature-dependent investigations strongly suggest a superparamagnetic behavior
Carnevale, Santino D. "Catalyst-free III-nitride Nanowires by Plasma-assisted Molecular Beam Epitaxy: Growth, Characterization, and Applications." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1374066626.
Повний текст джерелаHaubold, Danny, Annett Reichhelm, Alexander Weiz, Lars Borchardt, Christoph Ziegler, Lydia Bahrig, Stefan Kaskel, Michael Ruck, and Alexander Eychmüller. "The Formation and Morphology of Nanoparticle Supracrystals." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-209752.
Повний текст джерелаBaltazar, Jose A. "Polycyclic aromatic hydrocarbons: exploring new processes and materials for electronics." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/51787.
Повний текст джерелаZhang, Kai. "Molecular beam epitaxy growth and structural property of self-assembled InAs quantum dots on GaAs." [S.l. : s.n.], 2000. http://www.sub.uni-hamburg.de/disse/240/Disskai.pdf.
Повний текст джерелаMukai, Kohki. "Growth and Characterization of Self-Assembled InGaAs/GaAs Quantum Dots and Their Application to Lasers." Kyoto University, 2000. http://hdl.handle.net/2433/151537.
Повний текст джерелаKyoto University (京都大学)
0048
新制・論文博士
博士(工学)
乙第10504号
論工博第3541号
新制||工||1192(附属図書館)
UT51-2000-P671
(主査)教授 藤田 茂夫, 教授 北野 正雄, 教授 野田 進
学位規則第4条第2項該当
Niu, Xiaobin. "Level-set simulations of self-assembled nano patterns and stacked quantum dots during heteroepitaxial growth." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1610041041&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Повний текст джерелаBejarano, Villafuerte Ángela. "Self-assembled monolayers and patterned surfaces derived from them as templates for the growth of chiral crystals." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/123572.
Повний текст джерелаThe research presented in this Thesis has as the main objective of the establish the effect of chiral self-assembled monolayers (SAMs) on the nucleation and the crystal growth of organic compound, and find conditions which favour heterogeneous nucleation and subsequent growth. The possibility to control crystallization processes using self-assembled monolayers is an extremely interesting and promising approach in organic materials. This control has achieved by the use of inorganic crystalline substrates where nucleation is induced via epitaxy, although organic single crystals and SAMs have been used to control the polymorphic selectivity of the compound to crystallize, which is based on the lattice match between the molecular cluster and crystalline substrate terraces. According to this concept, SAMs have been used as controlled nucleation centres. This research describes the study in order to achieve the controlled crystallization of the compound phencyphos and diastereomeric salts on functionalized surfaces, and shows the differences between homogenous SAMs and combined SAMs (Microcontact printing method). The controlled crystallisation study starts with the formation of SAMs on gold with a novel chiral thiol, which has potential for nucleating crystal growth, (phencyphos 4-methylenthiol, PMT), and the crystallisation of phencyphos on them. The functionalisation of gold with monolayers of this compound has provided significant results due to its demonstrated influence in the crystallisation process. Thus, the successful functionalisation of the gold substrate by this resolving agent type molecule provided the chiral property to the self-assembled monolayer on gold. Phencyphos crystallises on PMT monolayer following different orientations and grow off the surface; depending on the solvent used these crystals grow as branched crystals (in isopropanol) on the functionalised surface. The microcontact printing method favours the mass transport to the desired thiol, minimizing evaporation effect at small scale. The surface combined of PMT and dodecanethiol has been the key for the development of surfaces which can induce the nucleation process on surface. On micropatterned surfaces, phencyphos crystallizes following a preferential orientation. Crystal growth is highly depending on the solvent used to crystalize phencyphos. The same enantiomer of phencyphos crystallized in different solvent (Chloroform and Isopropanol), yield different crystal growth, because the heterogeneous nucleation is effective when the solvent is allowed to evaporate slowly from the surface, allowing good mass transport to the desired regions. The diastereomeric salt most studied and presented here is the one formed by a phencyphos derivate, p-methyl phencyphos which provides a pair of crystalline salts with chiral amines. X-ray crystal structure of this diastereomeric salt reveal 10-membered rings constructed through hydrogen bonds, in which two ammonium groups formally replace phencyphos molecules seen in the phencyphos hydrate structure. The hydrogen bonds are strong and provide several polar faces to the crystalline structure, thus diastereomeric salts should have their crystals templated easily on polar SAM. There are several parameters that also have a dramatic influence on the crystallisation process such as the pattern shape and size which are critical. Thus the motif size which presents better results of favour the nucleation is for dots of 5 μm diameter spaced by 10 μm, for both crystallisation systems. The Dutch resolution has been also studied on micropatterned surfaces. The complexity of the family type crystallisation will require the development of specific additives to favour heterogeneous nucleation.
Bollani, Monica. "Self-assembled monolayer (SAM) sensors realisation on Si (001) : surface modification, film growth, SAM and sensor characterisation." Aix-Marseille 3, 2000. http://www.theses.fr/2000AIX30072.
Повний текст джерелаCe travail porte sur l'investigation et la recherche des methodes du syntesis pour lier à la surface du Si (001) des monocouches organiques. Nous avons évalué l'applicabilité de ces systèmes pour le développement du nano-dispositif dans le domaine du détecteurs. La première partie de cette thèse regarde la préparation de la surface : on a évalué comment la methode du nettoyage (RCA) utilisée pour éliminer la contamination à la surface détermine une modification sur la structure des premières couches du silicone. Par HRTEM et EELS on a demostré que la variation de la distance des paramètres réticulaires des première couches, c'est dû au passage d'oxidation nommé APM qui permit la diffusion et l'insertion du 0 dans le volume du Si. .
Al-Brasi, Enteisar. "The growth and characterization of films of noble metal nanocrystals and inorganic semiconductors at the interface of two immiscible liquids." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/the-growth-and-characterization-of-films-of-noble-metal-nanocrystals-and-inorganic-semiconductors-at-the-interface-of-two-immiscible-liquids(5652496a-6e6d-4e91-a21b-6ae1b3f36a87).html.
Повний текст джерелаTeng, Die. "Computational studies of transition metal nanoclusters on metal-supported graphene moiré." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51830.
Повний текст джерелаKirtland, David Rand. "Preparation of Heparin Surface for Quantification of Fibroblast Growth Factor-2 (FGF-2) Binding Using Surface Plasmon Resonance (SPR)." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33265.
Повний текст джерелаMaster of Science
Pithan, Linus. "On the role of external stimuli to tailor growth of organic thin films." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2017. http://dx.doi.org/10.18452/17749.
Повний текст джерелаThe research performed in the framework of this thesis focuses on new strategies to effectively control the growth of crystalline thin films of functional organic molecules and attributes the quest for additional growth control parameters in organic molecular beam deposition (OMBD). First the influence of light on the growth process of the sexithiophene (6T) is studied. We find that 6T thin films deposited as conventional in dark environments on KCl exhibit a bimodal growth with phase coexistence of two crystal polymorphs. In contrast, films grown under illumination with 532 nm light show increased phase purity. Further, we establish light-directed molecular self-assembly (LDSA) to generate permanently aligned thin films of tetracene (C18H12) and demonstrate direct patterning with light. Polarized light illumination leads to azimuthally photoaligned films on isotropic, amorphous substrates. Thus, LDSA can be regarded as a new degree of freedom in the quest for control-parameters in organic thin film growth. Next the impact of dynamic temperature oscillations on the time scales of molecular monolayer growth during organic molecular beam deposition is discussed. We strongly increase the island density during nucleation and selectively increase interlayer diffusion at later stages of monolayer growth. We analyse the interplay between molecular interlayer transport and island sizes to understand kinetic processes during growth. In a fourth experiment we show how thermal annealing can be used to improve smoothness and to increase the lateral size of crystalline islands of n-alkane (TTC, C44H90) films. We employ real-time optical phase contrast microscopy to track the diffusion across monomolecular step edges which causes the unusual smoothing during annealing. We rationalise the smoothing behaviour with the highly anisotropic attachment energies and low surface energies of TTC.
Ferreira, Rafael Cintra Hensel 1989. "Estudo do crescimento de filmes nanoestruturados automontados por adsorsão física utilizando medidas de capacitância = Growth study of self-assembled nanostructured films using capacitance measurements." [s.n.], 2016. http://repositorio.unicamp.br/jspui/handle/REPOSIP/330785.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
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Resumo: Os filmes orgânicos ultrafinos tem permitido funcionalizar superfícies a fim de introduzir propriedades específicas que diferem daquelas apresentadas em escala macroscópica. Um processo versátil para modificar superfícies e criar sistemas multifuncionais é a técnica de automontagem por adsorção física (LbL, do inglês Layer-by-Layer), na qual nanoestruturas são formadas devido a adsorção de moléculas com cargas opostas em arquiteturas moleculares multicamadas. O monitoramento elétrico do crescimento dos filmes é essencial em experimentos nos quais não são permitidas caracterizações ópticas. Além disto, é importante compreender as propriedades elétricas destes filmes devido a sua utilização em sensores capacitivos para análise química. Deste modo, neste trabalho desenvolvemos um equipamento capaz de acompanhar o crescimento de filmes LbL por meio de medidas de capacitância após a deposição de cada camada de polieletrólitos sobre eletrodos interdigitados (IDEs, do inglês Interdigitated Electrodes). Observamos um aumento linear da capacitância devido ao acúmulo de material dielétrico sobre os IDEs, com uma alternância na medida de capacitância de acordo com o polieletrólito depositado, isto é, há uma reversão de carga na camada mais externa quando a adsorção do policátion é compensada pela do poliânion, ou vice-versa. Utilizando o modelo para o potencial eletrostático de um IDE proposto por M. W. Den Otter, desenvolvemos uma nova metodologia para investigar a constante dielétrica da estrutura multicamadas formada. Obtivemos (16 ± 1) para a constante dielétrica do filme LbL (PDDA/CuTsPc), e (21 ± 3) para a arquitetura (PDDA/PSS), ambos em satisfatória concordância com a literatura. Ademais, desenvolvemos um modelo para interpretar o deslocamento na capacitância medida após a adsorção do policátion a fim de determinar sua densidade de carga superficial, que diminuiu de (0,23 ± 0,02) e/µm2 para (0,08 ± 0,01) e/µm2 quando o PDDA (policátion fortemente carregado) foi substituído pelo PAH (policátion fracamente carregado) para ambos os poliânions analisados. Portanto, desenvolvemos um equipamento para monitorar o crescimento de filmes LbL e uma metodologia que permite obter informações sobre o comportamento dielétrico dos filmes a cada camada depositada, o que pode auxiliar na escolha dos materiais e espessura dos filmes LbL utilizados como elementos transdutores em desenvolvimentos futuros
Abstract: Organic ultrathin films have enabled surface¿s functionalization in order to introduce specific properties which differ from those in macroscopic scale. A versatile process to modify surfaces and create multifunctional systems is the layer-by-layer (LbL) technique, in which the nanostructures are formed due to the adsorption of charged molecules in multilayered molecular architectures. The electrical monitoring of the film's growth is essential in experiments in which optical characterizations can not be used. Moreover, it is important to comprehend the electrical properties of these films owing to their application on capacitive sensors for chemical analysis. In this research we developed a home-made setup to keep track of the LbL film¿s growth by measuring the capacitance after each deposited layer onto interdigitated electrodes (IDEs). We have observed a linear increase in the capacitance due to accumulated dielectric material onto the IDEs, along with an alternation in the measured capacitance according to the deposited polyelectrolyte, i.e., a charge reversal of the outermost layer as the polycation adsorption is compensated by the polyanion adsorption, or vice-versa. Using the IDEs electrostatic potential model proposed by M. W. Den Otter, we have developed a new methodology to investigate the dielectric constant of the formed multilayered structure. A dielectric constant of (16 ± 1) was obtained for (PDDA/CuTsPc) films and (21 ± 3) for (PDDA/PSS) architecture, both in satisfactory agreement with the literature. Furthermore, we have developed a model to interpret the capacitance measurement shift after the polycation adsoption in order to investigate its surface charge density, which decreased from (0.23 ± 0.02) e/µm2 to (0.08 ± 0.01) e/µm2 when PDDA (strong polycation) was replaced by PAH (weak polycation) for both analyzed polyanions. Therefore, we have developed an equipment to monitor the LbL film's growth as well as a methodology that enables the obtaining of information about the film dielectric behavior at each deposited layer, which can assist in the choice of the materials and thickness of the LbL films that are used as transductor elements in future developments
Mestrado
Física
Mestre em Física
147530/2014
CNPQ
Yumnam, Nivedita [Verfasser], Veit [Akademischer Betreuer] Wagner, Veit [Gutachter] Wagner, Dietmar [Gutachter] Knipp, Jürgen [Gutachter] Fritz, and Jean [Gutachter] Geurts. "Self-Assembled Monolayer-Tuned Growth of ZnO Nanorods for Organic Solar Cells / Nivedita Yumnam ; Gutachter: Veit Wagner, Dietmar Knipp, Jürgen Fritz, Jean Geurts ; Betreuer: Veit Wagner." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2018. http://d-nb.info/1160086451/34.
Повний текст джерелаDang, Phuong Ngoc. "READILY IMPLANTABLE HIGH DENSITY STEM CELL SYSTEMS WITH CONTROLLED GROWTH FACTOR PRESENTATION FROM BIOACTIVE MICROPARTICLES FOR BONE REGENERATION VIA ENDOCHONDRAL OSSIFICATION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1421864780.
Повний текст джерелаFox, Michael Jacob. "Stochastic self-assembly." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34741.
Повний текст джерелаSpanton, Robert. "Stateful self-assembly." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/355888/.
Повний текст джерелаChen, Ho-Lin. "Robust self-assembly /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Повний текст джерелаOurdjini, Oualid. "Etude par microscopie à effet tunnel de la croissance de polymères 2D sur des surfaces métalliques." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4315/document.
Повний текст джерелаThe growth of two dimensional polymers has been studied under ultra-high vacuum on metallic surfaces by scanning tunnelling microscopy (STM). The first study relates on the growth of two dimensional covalent nanoporous networks obtained after dehydratation reaction of the 1,4 diboronic acid benzene molecule (BDBA). The best networks have been obtained with high molecular flux on silver metallic substrates maintained at 150°C during deposition. The second study relates on chemical reaction between the 1, 2, 4, 5 tetracyanobenzene molecule (TCNB) and iron atoms. The reaction takes place after an annealing at 200°C. In that case some iron octacyanophthalocyanine have been successfully synthesised at surfaces. This work opens new perspectives for the fabrication of 2D original materials by chemical reactions on surfaces
Diebold, Morgane. "Systèmes composites organogélateurs/polymères semi-conducteurs : de la preuve conceptuelle aux matériaux nanostructurés pour l'électronique plastique." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAE002.
Повний текст джерелаImproving the performances of organic photovoltaic devices requires morphology control of the active layers. Highly nanostructured donor-acceptor bulk heterojunctions were prepared by heterogeneous nucleation of poly (3-hexylthiophene) (P3HT, donor) on naphthalene diimide organogelators fibers (NDI, acceptor). The first part of this work was dedicated to the self-assembly of NDI-core organogelators substituted by amide groups and trialkoxyphenyls dendrons. We evaluated the influence of the flexible chain between the naphthalene core and the amide groups (2 C-C bonds for NDI2 and 4 for NDI4) on the physico-chemical properties of the organogelators.The second part of this work focused on the polymorphism of NDI2 with identification of four different polymorphs with their optical, spectroscopic and structural signatures. A phase diagram of NDI2 in the solid state was determined. The last part of this manuscript concerns the fabrication of donor-acceptor nano-composites between NDI organogelators and P3HT. The formation process in solution of these nano-composites was analyzed by following the crystallization kinetics of P3HT by UV-Vis absorption spectroscopy and the thin film morphology (shish-kebab structures) by transmission electron microscopy. The nucleating effect of various organogelators on P3HT was demonstrated. Solar cells were made from the composites P3HT:PCBM : organogelator and their energetic conversion yield was shown to be increased in the presence of organogelators
Dillenback, Lisa M. Keating Christine Dolan. "Self-assembly and controlled assembly of nanoparticles." [University Park, Pa.] : Pennsylvania State University, 2008. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-2613/index.html.
Повний текст джерелаVarghai, Daniel. "Tubular Tissue Engineered Scaffold-Free High-Cell-Density Mesenchymal Condensations For Femoral Defect Regeneration." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1497222797338966.
Повний текст джерелаWilliams, Richard James. "Enzyme assisted self-assembly." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496231.
Повний текст джерелаDe, Vet Christiaan J. F. "Auto-assemblage d'un anthacène fluorescent aux échelles nano- et micrométriques par photoréaction contrôlée." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0333/document.
Повний текст джерелаThe spatial and temporal control of the self-assembly of fluorescent molecules into organized nano-objects and into soft materials was achieved by photochemistry. The quantitative photodecarbonylation of the progelator dkDDOA under irradiation generates the supergelator 2,3-didecyloxyanthracene (DDOA) at room temperature and simultaneously gelates DMSO. dkDDOA is reactive under excitation withblue light due to the light sensitive alpha-diketone moiety that is added to the aromatic core.Additional colour-tuning from blue to green emission from the gel was achieved by adding a similar photoreactive 1,2-diketone-5,12-diphenyltetracene that yields a green emissive 5,12-diphenyltetracene sensitized through an efficient energy transfer. Under a microscope, focused laser irradiation enables the patterning of blue-emissive nanofibers on to a glass surface. Although the surface is non-treated, micropatterns of highly aligned DDOA nanofibers can be obtained. These surfaces emit linearly polarized blue light,as proven with polarization microscopy. The high anisotropy and the orientation of the fibers was achieved by controlling the nucleation density and the direction of scanning of the focused laser. Perpendicularly oriented micropatterns can thereby be juxtaposed on the same surface
Mayans, Tayadella Enric. "Self-assembly of phenylalanine derivatives." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461917.
Повний текст джерелаEn aquesta tesis, nous homooligopèptids derivats de fenilalanina ha estat sintetitzats per tal d'estudiar la seva capacitat d'autoorganització i examinar la influencia de l'estructura química i les condicions externes. Encara que les interaccions NH3+···-OOC cap-a-cua en els homopèptids desprotegits mostren estabilitzar les estructures peptídiques, s'han introduït funcionalitzacions químiques a través de la incorporació de proteccions a N- i C-, com per exemple, grups bloquejadors aromàtics, grups d'acoblament azida-alquí, l'anió trifluoroacetat o un bloc de polilàctide. Diferents capítols estan dedicats a mostrar que la llargada del bloc d'homopèptid també juga un paper rellevant en l'organització supramolecular dels derivats de fenilalanina. Els resultats publicats evidencien no només el control que exerceixen les característiques de l'ambient sinó també del substrat. Les interaccions pèptid··· pèptid, pèptid···superfície i la rugositat superficial han estat assenyalades com a factors clau que defineixen la forma, les dimensions i l'estabilitat de les estructures jerarquitzades.