Rozprawy doktorskie: „Polymer simulations”

1

Barakos, George. "Viscoelastic simulations in polymer processing". Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6497.

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The scope of this thesis is the mathematical modelling and the numerical simulation of polymer processing. In recent years there has been considerable progress in understanding and modelling phenomena related to flow of polymer melts through polymer processing machinery. Much of the progress is due to the numerical solution of integral-type constitutive equations relating stress and deformation and representing the fading memory of these fluids. In this direction, an integral constitutive equation of the K-BKZ type has been used for simulating the extrusion of a Low-Density Polyethylene melt (IUPAC LDPE sample A). The influence of temperature has also been examined by performing a complete non-isothermal flow simulation. In addition, simulations have been performed for the well-known phenomenon of extrudate bending, when extrusion is performed through a flat die with walls kept at different temperatures. The simulations reveal that the combination of viscous and elastic phenomena result in a significant swelling of the extrudate characterized by a profound asymmetry. Finally, a comparison has been performed of different polyethylene melts based on the predictions of the model used. The results reveal the intense viscoelastic character of the LDPE and show clearly the importance of viscoelasticity in polymer processing. Moreover, they give a wealth of information about the influence of material properties on polymer behaviour during processing especially as far as vortex growth and extrudate swell diameter are concerned. (Abstract shortened by UMI.)

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2

Chakraborty, S. "Structural, dynamical properties of polymers and polymer composites from multiscale simulations". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2016. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2072.

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Consiglio, Armando. "Molecular dynamics simulations of conducting polymer nanocomposites". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18454/.

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Among the conducting polymers, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is one of the most used materials in the field of bioelectronics due to its biocompatibility, chemical stability and high electronic as well as ionic charge transport mobilities. Despite many experimental findings, a microscopic understanding of the materials electronic properties is currently elusive; the main reason is the lack of structural atomistic data of the polymer blend, that is, difficult to obtain because of the disordered and nano-crystalline morphology. In this thesis work we develop and use Molecular Dynamics based methods to simulate the structure of PEDOT:PSS in presence of an interface, investigating how a surface and some physical quantities (temperature, water content and electric charge on PEDOT oligomers) would introduce order to the evolving structure, and pointing out the differences between interfacial and bulk behaviour. The results obtained by computer simulations are used to estimate experimentally accessible parameters and to compare them with already existing experimental data.

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4

Vliet, Johannes Henricus van. "Monte Carlo simulations of confined polymer systems". [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 1991. http://irs.ub.rug.nl/ppn/293041210.

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Galuschko, André. "Molecular dynamics simulations of sheared polymer brushes". Strasbourg, 2010. https://publication-theses.unistra.fr/public/theses_doctorat/2010/GALUSCHKO_Andre_2010.pdf.

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Erguney, Fatih M. "COARSE-GRAINED MC SIMULATIONS OF POLYMER NANOCOMPOSITES". University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1176404164.

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Drewniak, Marta. "Computer Simulations of Dilute Polymer Solutions: Chain Overlaps and Entanglements". Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc278086/.

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Chain conformations and the presence of chain overlaps and entanglements in dilute polymer solutions have been analyzed. The fundamental problem of existence of chain overlaps in dilute solutions is related to the drag reduction phenomenon (DR). Even though DR occurs in solutions with the concentration of only few parts per million (ppm), some theories suggest that entanglements may play an important role in DR mechanism. Brownian dynamics technique have been used to perform simulations of dilute polymer solutions at rest and under shear flow. A measure of interchain contacts and two different measures of entanglements have been devised to evaluate the structure of polymer chains in solution. Simulation results have shown that overlaps and entanglements do exist in static dilute solutions as well as in solutions under shear flow. The effect of solution concentration, shear rate and molecular mass have been examined. In agreement with the solvation theory of DR mechanism, simulation results have demonstrated the importance of polymer + polymer interactions in dilute solutions.

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Eichinger, David Albert. "Non-Lattice Monte Carlo Simulations of Polymer Motion". W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539625515.

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Ethier, Jeffrey. "Molecular Dynamics Simulations of Adsorbed Polymer-Grafted Nanoparticles". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555426585455568.

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Karasawa, Naoki Goddard William A. Goddard William A. "Simulations of polymer crystals : new methods and applications /". Diss., Pasadena, Calif. : California Institute of Technology, 1992. http://resolver.caltech.edu/CaltechETD:etd-08062007-104316.

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Patel, Reena R. "Molecular dynamics simulations of polymer nanocomposites containing polyhedral oligomeric silsesquioxanes". MSSTATE, 2004. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04082004-135524/.

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Molecular dynamics simulations were carried out on traditional polymers copolymerized with POSS (Polyhedral Oligomeric Silsesquioxanes) derivatives to identify the reason behind improved properties imparted to the conventional polymers with the chemical incorporation of POSS. Two classes of systems are used in the present study, namely the polystyrene and polymethyl methacrylate systems. Seven systems are studied in the polystyrene class. The effect of corner substituent groups of the POSS cage on the properties of the polymer nanocomposites was studied using the polystyrene. In addition, the effect of the type of cage structure on the properties was studied using T8, T10 and T12 POSS cage structures containing phenyl substituents on each POSS cage. Systems with polymethyl methacrylate were studied to analyze the effect of mole percent of POSS on the polymer properties, holding the corner substituents on the POSS unit constant. The corner function used was the isobutyl group. The properties analyzed using simulations include glass transition temperature, volumetric thermal expansion coefficient, X-ray scattering data, solubility parameter and mechanical properties. In both polystyrene and polymethyl methacrylate systems, simulations were also carried out on the pure parent polymers for the sake of comparison. The effect of forcefield on the predicted properties was studied using both COMPASS and PCFF forcefields. Performance analysis of the code used in the present simulation was done by analyzing the parallel run time of simulations involving pure atactic polystyrene.

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12

Aung, Pyie Phyo. "Monte Carlo Simulations of charge Transport in Organic Semiconductors". University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1418272111.

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Kamerlin, Natasha. "Computer Simulations of Polymer Gels : Structure, Dynamics, and Deformation". Doctoral thesis, Uppsala universitet, Fysikalisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-332575.

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This thesis presents the results of computer simulation studies of the structure, dynamics, and deformation of cross-linked polymer gels. Obtaining a fundamental understanding of the interrelation between the detailed structure and the properties of polymer gels is a challenge and a key issue towards designing materials for specific purposes. A new off-lattice method for constructing a closed network is presented that is free from defects, such as looping chains and dangling ends. Using these model networks in Brownian dynamics simulations, I show results for the structure and dynamics of bulk gels and describe a novel approach using spherical boundary conditions as an alternative to the periodic boundary conditions commonly used in simulations. This algorithm was also applied for simulating the diffusion of tracer particles within a static and dynamic network, to illustrate the quantitative difference and importance of including network mobility for large particles, as dynamic chains facilitate the escape of particles that become entrapped. I further investigate two technologically relevant properties of polymer gels: their stimuli-responsive behaviour and their mechanical properties. The collapse of core-shell nanogels was studied for a range of parameters, including the cross-linking degree and shell thickness. Two distinct regimes of gel collapse could be observed, with a rapid formation of small clusters followed by a coarsening stage. It is shown that in some cases, a collapsing shell may lead to an inversion of the core-shell particle which exposes the core polymer chains to the environment. This thesis also explores the deformation of bimodal gels consisting of both short and long chains, subject to uniaxial elongation, with the aim to understand the role of both network composition as well as structural heterogeneity on the mechanical response and the reinforcement mechanism of these materials. It is shown that a bimodal molecular weight distribution alone is sufficient to strongly alter the mechanical properties of networks compared to the corresponding unimodal networks with the same number-average chain length. Furthermore, it is shown that heterogeneities in the form of high-density short-chain clusters affect the mechanical properties relative to a homogeneous network, primarily by providing extensibility.

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14

Durand, Manuel. "Molecular dynamics simulations of oligomer diffusion in polymer melts". Strasbourg, 2010. http://www.theses.fr/2010STRA6123.

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Cette thèse s’inscrit dans le cadre du programme de recherche COPOLA (“COmposite POlymer Ageing”) du CNRS. La dynamique de chaînes courtes dans des systèmes composés de chaînes homologues (système monodisperse) et dans une matrice composée de chaînes beaucoup plus longues et enchevêtrées (système polydisperse) est étudiée de façon systématique par simulation de la dynamique moléculaire. Deux modèles gros-grains génériques de type bille-ressort sont étudiés : le modèle de chaînes flexibles et celui des chaînes semi-flexibles. Les effets de la longueur de chaîne, entre N = 1 et N = 64 monomères et de la température, de T = 1 (en unité Lennard-Jones) jusqu’à la température de transition vitreuse T g, sont étudiés. Les propriétés statiques et dynamiques des deux systèmes sont analysées respectivement dans le cadre de la théorie de Rouse et du modèle de chaîne à rotation libre. La dépendance du coefficient de diffusion (D) avec la longueur de chaîne N est décrite par une loi de puissance telle que D / N−®. Des exposants ® sont trouvés supérieurs à 1 et dépendent de la température pour les systèmes monodisperses. Au contraire, des exposants ® = 1 sont determinés pour les systèmes polydisperses indépendamment de la rigidité du traceur ou de celle de la matrice hôte. Pour les chaînes flexibles des systèmes monodisperses, les résultats de simulation sont réconciliés avec la théorie de Rouse en prenant en compte la dépendance du coefficient de friction avec la longueur de chaîne. La prédiction du coefficient de diffusion à partir de ce temps court échoue cependant pour les systèmes monodisperses semi-flexibles. Ce résultat est attribué au changement des propriétés statiques et des effets d’enchevêtrement additionels. Un modèle d’activation est déduit avec succès en introduisant une dynamique de cage caractérisant les déplacements des monomères et avec une hypothèse d’indépendance des déplacements des monomères. Une prédiction précise des valeurs de D à partir d’un temps court de référence (déterminé à T = 1 et P = 5) est obtenue pour toutes les conditions de températures (entre T = 1 et 0. 26), de pressions (entre P = 1 et 8) et pour des longueurs de chaînes entre N = 1 et 16. L’exposant ® obtenu pour les diffusants dans la matrice est en accord avec un résultat expérimental dans un fondu mais est en contradiction avec des valeurs acquises dans des solides. Les éventuelles causes de déviations sont discutées et des comparaisons avec des données expérimentales pour la dépendence de l’énergie d’activation avec la température et la longueur de chaînes sont proposées. Finalement, des directions de recherches complémentaires et les conséquences technologiques associées à ce travail sont suggérées
This thesis is part of the CNRS research programme COPOLA, “COmposite POlymer Ageing”, and analyzes systematically via molecular dynamics simulations the dynamics of short chains diffusing among themselves (so-called monodisperse systems) and in a matrix of much longer entangled chains (so-called polydisperse systems). Results are presented for two molecular models of polymer chains, involving either flexible or semi-flexible chains. Effects of chain lengths, from N = 1 up to N = 64, and temperatures, from T = 1 (Lennard-Jones units) down to the glass transition temperature T g, are investigated. Static and dynamic properties of both systems are analyzed within the framework of Rouse theory and with a freely rotating chain model, respectively. A power law dependence of diffusion coefficients (D) on N is found: D / N−®. Scaling exponents greater than 1 and depending on temperature are inferred for monodisperse systems whereas unitary ® values are obtained in polydisperse systems regardless the host/tracer chain stiffness. For flexible monodisperse chains, simulated results are reconciled with Rouse theory by considering that the friction coefficient, derived from monomeric relaxation times, depends on both temperature and chain length. This extrapolation of long time dynamics from short relaxation times fails however in monodisperse semi-flexible systems, due to a change in static properties with temperature and additional entanglement effects. An activation model of trace diffusion is successfully inferred by introducing a cage-like dynamics for monomer displacements and an assumption of independence of monomer displacements (compatible with Rouse theory). Accurate predictions of D from a reference short relaxation time (assessed at T = 1 and P = 5) are achieved for all tested conditions of temperature (between 1 and 0. 26), pressure (between 1 and 8) and N ranging from N = 1 to 16. Proposed scaling of trace diffusion of oligomers in an entangled matrix matches experimental results in melts [?] but deviates from values determined in solids [?,?]. Possibly sources of discrepancy are discussed and additional comparisons involving the dependence of activation energies on chain length and temperature are proposed. Finally, complementary directions of research and technological consequences of the current study are suggested

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15

Borglum, Joshua Christopher. "Numerical Simulations of Electrohydrodynamic Evolution of Thin Polymer Films". Thesis, North Dakota State University, 2015. https://hdl.handle.net/10365/27736.

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Recently developed needleless electrospinning and electrolithography are two successful techniques that have been utilized extensively for low-cost, scalable, and continuous nano-fabrication. Rational understanding of the electrohydrodynamic principles underneath these nano-manufacturing methods is crucial to fabrication of continuous nanofibers and patterned thin films. This research project is to formulate robust, high-efficiency finite-difference Fourier spectral methods to simulate the electrohydrodynamic evolution of thin polymer films. Two thin-film models were considered and refined. The first was based on reduced lubrication theory; the second further took into account the effect of solvent drying and dewetting of the substrate. Fast Fourier Transform (FFT) based spectral method was integrated into the finite-difference algorithms for fast, accurately solving the governing nonlinear partial differential equations. The present methods have been used to examine the dependencies of the evolving surface features of the thin films upon the model parameters. The present study can be used for fast, controllable nanofabrication.

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16

Blonski, Slawomir. "Computer Simulations of Mechanical Behavior of Polymer Liquid Crystals". Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc332725/.

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In this dissertation molecular dynamics simulations of behavior of polymer liquid crystals (PLC's) under tensile deformation have been performed. PLC's composed of random or block copolymers of rigid and flexible segments have been studies. Systems of fully flexible chains have been simulated for comparison. Stress-strain relations and fracture mechanics have been investigated.

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17

Wagner, Lukas. "Simulations of fluid and polymer dynamics with discrete methods /". The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487935125881663.

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Meleshko, Glib. "Polymer-drug delivery : combining computer simulations and experimental techniques". Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/78537/.

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The conformation that polymer-drug conjugates form in solution have a significant effect on properties that are important for designing of drug delivery systems. For N-(2- hydroxypropyl)methacrylamide (HPMA) copolymer conjugates it is known that aggregation number, size and shape affect the rate at which a drug is enzymatically cleaved from the polymer backbone. Investigation of conformational properties could lead to creation of polymeric systems with the ability to keep drug levels at biologically active and safe concentrations for desired period of time. This project is focused on establishing the required modeling methodologies to describe the solution configurations of HPMA based conjugates. Therefore structural properties such as size, shape and density distribution of a range of HPMA copolymers have been investigated. The suitability of atomistic force fields has been assessed against rotational barriers and relative conformational energies obtained from ab initio and DFT data for a monomer and dimer of HPMA. Following this, the AMBER99 parameter set was chosen for all molecular dynamics simulation. Radius of gyration (Rg), radial distribution function (RDF), shape, and density profiles of particular atom types were calculated for a range of HPMA homopolymers sizes from 4 to 200 repeat units (2 to 35 kDa). Results were interpreted in the context of Flory’s mean field approach, and compared with data obtained from small angle neutron scattering (SANS) experiments. Results of this study were used for investigation of HPMA conjugates with drug mimics. A range of linear amines (aminohexane(C6), aminooctane(C8), aminododecane (C12)), hydroxyl and fluoro terminated linear amines as well as aromatic aminoanthracene (ANC), aminocrysene (AC) and aminoanthraquinone (ANQ), bound to the polymeric carrier via a tetrapeptide linker (glycinephenylalanine- leucine-glycine) (GFLG) (Mw ~ 30 kDa) were selected as model objects for study of the effect of drug type and loading on HPMA copolymer conformation. Using obtained results for further investigation we have progressed to more complex systems of mixed polymer conjugates containing drug-mimic parts with similar parameters of hydrophobicity, but different in terms of flexibility for drug-mimic chain. In order to provide corresponding comparison we have selected systems of Adamantane (Ad)/ANC, Ad/ANQ, methyl-Adamantane (AdMe)/C12, hydroxyl-Adamantane (AdOH)/C10OH and Ad/C10 conjugate iii mixtures and investigated the effect of changing ratio of drug-mimic parts for these systems. Analysis of SANS data revealed how conformation can be affected by the drug mimic’s intrinsic volume variation, and allowed us to get closer to finding answers for questions that can increase effective use of polymer-drug therapeutics. SANS experimental scattering curves were compared with theoretical curves, predicted from molecular dynamics (MD) simulations. Parameters such as size and shape fitted to SANS data were compared with relevant simulated structures. Based on results of previous studies as well as additional polymer synthesis and characterization process we were able to develop reliable all-atom (AA) and coarse-gain (CG) computer models for simulation of HPMA polymer. Required tools and software were developed. Various methods were used to increase performance efficiency of Molecular Dynamics calculations. Among them highest practical impact has a domain decomposition parallelization strategy.

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MANCA, FABIO. "The elastic behavior of polymer chains: theory and simulations". Doctoral thesis, Università degli Studi di Cagliari, 2013. http://hdl.handle.net/11584/266126.

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This thesis provides a picture on the thermo-elastic behavior of polymer molecules with biological relevance. In particular, this essay deals with the thermo-elasticity of single polymer molecules subjected to uniform stretching (generated by an applied force) or non-uniform stretching (generated by an external field). Analytical expressions and molecular dynamics simulations are elaborated considering some generalizations of the freely-jointed chain (FJC) and the worm-like chain (WLC) models. The analytical theory, based on classical statistical mechanics, allows a rigorous mathematical treatment, while the study of complex systems is covered by means of Monte Carlo simulations. On the one hand, the uniform stretching of a single polymer, imposed by an external pulling force, is pursued for studying the statistical mechanics of small molecules. When the thermodynamic limit is not satisfied, different boundary conditions (either Helmholtz or Gibbs ensemble) yield different elastic behavior, showing the fascinating intrication native to the thermodynamics of small systems. This complexity is shown to be even more suggestive when investigating bistable molecules of which domains exhibit transitions between two stable states. This scenario leads from cooperative to non-cooperative response of each domain to the external force, depending on the specific statistical ensemble considered. Universal scaling laws are provided, governing the overall elasticity of the polymer systems. On the other hand, the non-uniform stretching of a single molecule, imposed by an external field, is studied to analyze the average configurational properties of polymers and leads to another very intricating scenario concerning the behavior of the variances describing the fluctuations of the system. Furthermore, for the WLC model our attention fall in the investigation of the forceextension curve, for which we derive new approximated expressions for a chain immersed into an external field.

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Khanal, Kiran. "Monte Carlo simulations to study the effect of chain stiffness on static, dynamic, and equation-of-state properties of polymer melts". Akron, OH : University of Akron, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1251402309.

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Thesis (M.S.)--University of Akron, Dept. of Physics, 2009.
"August, 2009." Title from electronic thesis title page (viewed 10/21/2009) Advisor, Jutta Luettmer-Strathmann; Committee members, Alper Buldum, Ben Yu-Kuang Hu; Department Chair, Robert R. Mallik; Dean of the College, Chand Midha; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

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Düchs, Dominik. "Field theories for copolymer blends self consistent approaches and Monte Carlo simulations /". [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967589339.

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Vliet, Roland Edward van. "Polymer-solvent liquid-liquid phase separation thermodynamics, simulations & applications /". [Amsterdam : Amsterdam : Instituut voor Technische Scheikunde, Universiteit van Amsterdam] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/64948.

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De, Joannis Jason. "Equilibrium properties of polymer solutions at surfaces Monte Carlo simulations /". [Florida] : State University System of Florida, 2000. http://etd.fcla.edu/etd/uf/2000/ane5947/dissertation%5Fdone.pdf.

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Thesis (Ph. D.)--University of Florida, 2000.
Title from first page of PDF file. Document formatted into pages; contains ix, 242 p.; also contains graphics. Vita. Includes bibliographical references (p. 232-241).

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Hamm, Marc. "Dynamic mean field simulations of liquid crystalline and amorphous (co)polymers : building a model for polymer joining". Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619528.

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Patel, Pritesh A. "POLYELECTROLYTE MULTILAYERS: SIMULATIONS, EXPERIMENTS, AND APPLICATIONS IN BIOMINERALIZATION". Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1193430461.

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Tretyakov, Nikita. "Molecular Dynamics simulations of polymer liquids on substrates of different topography". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://hdl.handle.net/11858/00-1735-0000-000D-F67D-3.

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Rosenthal, Lasse [Verfasser]. "Kinetic Monte Carlo Simulations of Metal-Polymer Nanocomposite Formation / Lasse Rosenthal". Kiel : Universitätsbibliothek Kiel, 2013. http://d-nb.info/1042440301/34.

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Venkatakrishnan, Abishek. "Molecular Simulations Study of Adsorption of Polymers on Rough Surfaces". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1427812323.

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Nilsson, Fritjof. "Simulations of Semi-Crystalline Polymers and Polymer Composites in order to predict Electrical, Thermal, Mechanical and Diffusion Properties". Doctoral thesis, KTH, Polymera material, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93519.

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Several novel computer simulation models were developed for predicting electrical, mechanical, thermal and diffusion properties of materials with complex microstructures, such as composites, semi-crystalline polymers and foams. A Monte Carlo model for simulating solvent diffusion through spherulitic semicrystalline polyethylene was developed. The spherulite model, based on findings by electron microscopy, could mimic polyethylenes with crystallinities up to 64 wt%. Due to the dendritic structure of the spherulites, the diffusion was surprisingly independent of the aspect ratio of the individual crystals. A correlation was found between the geometrical impedance factor (τ) and the average free path length of the penetrant molecules in the amorphous phase. A new relationship was found between volume crystallinity and τ. The equation was confirmed with experimental diffusivity data for Ar, CH4, N2 and n-hexane in polyethylene. For electrostatics, a novel analytical mixing model was formulated to predict the effective dielectric permittivity of 2- and 3-component composites. Results obtained with the model showed a clearly better agreement with corresponding finite element data than previous models. The analytical 3-component equation was in accordance with experimental data for nanocomposites based on mica/polyimide and epoxy/ hollow glass sphere composites. Two finite element models for composite electrostatics were developed. It is generally recognized that the fracture toughness and the slow crack growth of semicrystalline polymers depend on the concentrations of tie chains and trapped entanglements bridging adjacent crystal layers in the polymer. A Monte Carlo simulation method for calculating these properties was developed. The simulations revealed that the concentration of trapped entanglements is substantial and probably has a major impact on the stress transfer between crystals. The simulations were in accordance with experimental rubber modulus data. A finite element model (FEM) including diffusion and heat transfer was developed for determining the concentration of gases/solutes in polymers. As part of the FEM model, two accurate pressure-volume-temperature (PVT) relations were developed. To predict solubility, the current "state of the art" model NELF was improved by including the PVT models and by including chemical interactions using the Hansen solubility parameters. To predict diffusivity, a novel free-volume diffusion model was derived based on group contribution methods. All the models were used without adjustable parameters and gave results in agreement with experimental data, including recent data obtained for polycarbonate and poly(ether-etherketone) pressurized with nitrogen at 67 MPa.
QC 20120420

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Sharma, Arjun. "Molecular Dynamics Simulations of Stimuli-Responsive Polymers". ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/td/2275.

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Polymers that undergo dramatic changes in structural conformations in response to numerous stimuli such as temperature, pH, electric and magnetic fields, light inten- sity, biological molecules, and solvent polarity, are known as stimuli-responsive or ”smart” polymers. There is a broad range of very promising applications of these materials in catalysis, environmental remediation, sensors or actuator systems, and as delivery systems of therapeutic agents. Researchers have been trying to mimic smart polymers based on properties of polymers found in nature such as proteins, carbohydrates and nucleic acids. Novel bio-compatible polymers with a variety of chemical functional groups, diverse topologies, and cross-linking patterns with the ability to self-assemble in vivo are being engineered. Experimental and theoretical studies indicate that the thermodynamic properties relating to the hydrophobic effects play a pivotal role in determining the self-assembly process in smart polymers. At the same time, computational approaches based on simulation and modeling provide an understanding of this phenomenon on the micro- scopic level. Building empirical models based on statistical mechanics methods and simulation data helps to design polymeric materials with desirable traits. My research is mainly focused on investigating physicochemical characteristics of stimuli-responsive polymers under different conditions. I used atomistic molecular dynamics simulations to investigate these effects on polymer conformation. Given the size and complexity of our polymeric systems, we employed Graphical Process- ing Units (GPU) and enhanced sampling techniques such as REDS2 to increase the sampling time. These methods allow for the study of polymeric structural dynamics in solvents of varying polarity and in human skin epidermis. Our constant pH simulation of poly(methacrylic acid) revealed that the overall response is made up of local and global structural changes. The local structural re- sponse depends on the tacticity of the polymer, which leads to distinct cooperative effects for polymers with varying stereochemistry. Such simulations help to under- stand the principal driving forces behind the mechanism of self-assembly processes.

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Seo, Youngmi. "Structure and Dynamic Properties of Interfacially Modified Block Copolymers from Molecular Dynamics Simulations". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492628195548591.

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Alemaskin, Kirill. "ENTROPIC MEASURES OF MIXING IN APPLICATION TO POLYMER PROCESSING". Case Western Reserve University School of Graduate Studies / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1098397260.

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33

Billen, Joris. "Simulated Associating Polymer Networks". Scholarship @ Claremont, 2012. http://scholarship.claremont.edu/cgu_etd/51.

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Telechelic associating polymer networks consist of polymer chains terminated by endgroups that have a different chemical composition than the polymer backbone. When dissolved in a solution, the endgroups cluster together to form aggregates. At low temperature, a strongly connected reversible network is formed and the system behaves like a gel. Telechelic networks are of interest since they are representative for biopolymer networks (e.g. F-actin) and are widely used in medical applications (e.g. hydrogels for tissue engineering, wound dressings) and consumer products (e.g. contact lenses, paint thickeners). In this thesis such systems are studied by means of a molecular dynamics/Monte Carlo simulation. At first, the system in rest is studied by means of graph theory. The changes in network topology upon cooling to the gel state, are characterized. Hereto an extensive study of the eigenvalue spectrum of the gel network is performed. As a result, an in-depth investigation of the eigenvalue spectra for spatial ER, scale-free, and small-world networks is carried out. Next, the gel under the application of a constant shear is studied, with a focus on shear banding and the changes in topology under shear. Finally, the relation between the gel transition and percolation is discussed.

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Severin, Nikolai. "Molecular Dynamics Simulations of Polymers and Micelles at Interfaces". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 1999. http://dx.doi.org/10.18452/14449.

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Molekulardynamik (MD) Simulationen wurden an zwei verschiedenen Systemen durchgeführt: 1. Grenzfläche zwischen Polyethylen und isotaktischem Polypropylen (PE-iPP) und 2. Zylindrische Mizellen, bestehend aus Tetradecyltrimethylammoniumbromid (C14TAB), in wässriger Lösung und an Fest-Flüssig-Grenzflächen. Die allgemeinen Schwierigkeiten bei der Simulation von Grenzflächen kristalliner Polymere wurden diskutiert und eine Methode für solche Simulationen vorgeschlagen. Diese Methode wurde zur epitaxialen Kristallisation von PE auf iPP benutzt. Experimentelle Ergebnisse der epitaxialen Kristallisation konnten durch die Simulation bestätigt werden. Ferner konnte vorhergesagt werden, dass PE bevorzugt auf einer iPP-Oberfläche mit hoher Methylgruppenkonzentration kristallisiert. Ebenso wurde durch die MD Simulation vorhergesagt, dass PE in der Grenzflächenregion von einer orthorhombischen zur monoklinischen Kristallstruktur wechselt. Die Simulationsdauer für die Mizellen betrug einige Nanosekunden. Die Ergebnisse für die Mizellen in wässriger Lösung stehen hierbei in guter Übereinstimmung mit experimentellen Werten. Im Widerspruch zur allgemein üblichen Vorstellung führte die Simulation der Mizellen zur Ausbildung eines Hohlraums in ihrer Mitte sowie zu einer inhomogenen Dichte des hydrophoben Mizellkerns. Dies wurde zum Teil der inhomogenen Verteilung der terminalen Methylgruppen im Mizellkern zugeschrieben. Zylindrische und halbzylindrische Mizellen wurden an den Paraffin/Wasser- und Gold/Wasser-Grenzflächen simuliert.
Molecular Dynamic (MD) simulation of two different systems was performed: 1) Polyethylene- isotactic Polypropylene (PE-iPP) interfaces and 2) cylindrical micelles formed by tetradecyl trimethylammonium bromide (C14TAB) molecules in aqueous solution and at solid liquid interfaces. The general difficulties of simulation of polymer crystalline interfaces were discussed and one method was proposed for such simulations. Thise method was used to simulate epitaxial crystallisation of PE on iPP. The experimental results on epitaxial crystallisation were confirmed by MD simulation and in addition epitaxial crystallisation of PE on iPP surface with high dencity of methyl groups was predicted. MD simulation also predicted that PE should change at the interfacial region from the orthorhombic to monoclinic crystalline structure. Several nanoseconds of life of cylindrical micelles were simulated. The simulation results for the micelle in aqueous solution were favourably compared with experimental results. In contradiction to the standard picture of an ionic micelle the simulated micelle formed hole in its centre and the density of the hydrophobic micelle core was inhomogeneous. This effect partially was explained by the inhomogeneous distribution of the terminal methyl groups in the micelle core. Cylindrical and half cylindrical micelles of C14TAB molecules were simulated at the paraffin- and gold-aqueous interfaces.

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Fahmi, Zahra. "Study of 3D genome organisation in budding yeast by heterogeneous polymer simulations". Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/287470.

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Investigating the arrangement of the packed DNA inside the nucleus has revealed the essential role of genome organisation in controlling genome function. Furthermore, genome architecture is highly dynamic and significant chromatin re-organisation occurs in response to environmental changes. However, the mechanisms that drive the 3D organisation of the genome remain largely unknown. To understand the effect of biophysical properties of chromatin on the dynamics and structure of chromosomes, I developed a 3D computational model of the nucleus of the yeast S. cerevisiae during interphase. In the model, each chromosome was a hetero-polymer informed by our bioinformatics analysis for heterogeneous occupancy of chromatin-associated proteins across the genome. Two different conditions were modelled, normal growth (25°C) and heat shock (37°C), where a concerted redistribution of proteins was observed upon transition from one temperature to the other. Movement of chromatin segments was based on Langevin dynamics and each segment had a mobility according to their protein occupancy and the expression level of their corresponding genes. The model provides a significantly improved match with quantitative microscopy measurements of telomere positions, the distributions of 3D distances between pairs of different loci, and the mean squared displacement of a labelled locus. The quantified contacts between chromosomal segments were similar to the observed Hi-C data. At both 25°C and 37°C conditions, the segments that were highly occupied by proteins had high number of interactions with each other, and the highly transcribed genes had lower contacts with other segments. In addition, similar to the experimental observations, heat-shock genes were found to be located closer to the nuclear periphery upon activation in the simulations. It was also shown that the determined distribution of proteins along the genome is crucial to achieve the correct genome organisation. Hence, the heterogeneous binding of proteins, which results in differential mobility of chromatin segments, leads to 3D self-organisation.

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Sean-Fortin, David. "Highly Driven Polymer Translocation in the Presence of External Constraints: Simulations and Theory". Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35803.

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DNA sequencing via nanopore translocation was a pipedream two decades ago. Today, biotech companies are releasing commercial devices. Yet many challenges still hover around the simple concept of threading a long DNA molecule through a small nanoscopic pore with the aim of extracting the DNA’s sequence along the process. In this thesis I use computer simulations to create what are in essence virtual pro- totypes for testing design ideas for the improvement of nanopore translocation devices. These ideas are based on the general concept of modifying the average shape of the initial DNA conformations. This is done, for example, by introducing new geometrical features to the nanopore’s surrounding or by the means of some external force. The goal of these simulations is not just to test design improvements, but also to systematically deconstruct the physical mechanisms involved in the translocation process. The roles of pore friction, initial polymer conformations, monomer crowding on the trans- side of the membrane, Brownian fluctuations, and polymer rigidity can, with careful consideration, be essentially muted at will. Computer simulations in this sense play the role of a sandbox in which the physics can be tinkered with, in order to assess and evaluate the magnitude of certain approximations found in theoretical modelling of translocation. This enables me to construct theoretical models that contain the necessary features pertaining to the different designs tested by simulations. The work presented here is thus constituted of both Langevin Dynamics simulations and adaptations of the Tension-Propagation theory of polymer translocation when the polymer is subject to the various test conditions.

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Uddin, Nasir Mohammad Capaldi Franco Farouk Bakhtier. "Modeling and simulations of carbon nanotube (CNT) dispersion in water/surfactant/polymer systems /". Philadelphia, Pa. : Drexel University, 2010. http://hdl.handle.net/1860/3203.

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Bandorawalla, Tozer Jamshed. "Micromechanics-Based Strength and Lifetime Prediction of Polymer Composites". Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/26445.

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With the increasing use of composite materials for diverse applications ranging from civil infrastructure to offshore oil exploration, the durability of these materials is an important issue. Practical and accurate models for lifetime will enable engineers to push the boundaries of design and make the most efficient use of composite materials, while at the same time maintaining the utmost standards of safety. The work described in this dissertation is an effort to predict the strength and rupture lifetime of a unidirectional carbon fiber/polymer matrix composite using micromechanical techniques. Sources of material variability are incorporated into these models to predict probabilistic distributions for strength and lifetime. This approach is best suited to calculate material reliability for a desired lifetime under a given set of external conditions. A systematic procedure, with experimental verification at each important step, is followed to develop the predictive models in this dissertation. The work begins with an experimental and theoretical understanding of micromechanical stress redistribution due to fiber fractures in unidirectional composite materials. In-situ measurements of fiber stress redistribution are made in macromodel composites where the fibers are large enough that strain gages can be mounted directly onto the fibers. The measurements are used to justify and develop a new form of load sharing where the load of the broken fiber is redistributed only onto the nearest adjacent neighbors. The experimentally verified quasi-static load sharing is incorporated into a Monte Carlo simulation for tensile strength modeling. Very good agreement is shown between the predicted and experimental strength distribution of a unidirectional composite. For the stress-rupture models a time and temperature dependent load-sharing analysis is developed to compute stresses due an arbitrary sequence of fiber fractures. The load sharing is incorporated into a simulation for stress rupture lifetime. The model can be used to help understand and predict the role of temperature in accelerated measurement of stress-rupture lifetimes. It is suggested that damage in the gripped section of purely unidirectional specimens often leads to inaccurate measurements of rupture lifetime. Hence, rupture lifetimes are measured for [90/0_3]_s carbon fiber/polymer matrix specimens where surface 90 deg plies protect the 0 deg plies from damage. Encouraging comparisons are made between the experimental and predicted lifetimes of the [90/0_3]_s laminate. Finally, it is shown that the strength-life equal rank assumption is erroneous because of fundamental differences between quasi-static and stress-rupture failure behaviors in unidirectional polymer composites.
Ph. D.

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39

Hilbig, Travis. "Scratch Modeling of Polymeric Materials with Molecular Dynamics". Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc149608/.

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It is impossible to determine the amount of money that is spent every replacing products damaged from wear, but it is safe to assume that it is in the millions of dollars. With metallic materials, liquid lubricants are often used to prevent wear from materials rubbing against one another. However, with polymeric materials, liquid lubricants cause swelling, creating an increase in friction and therefore increasing the wear. Therefore, a different method or methods to mitigate wear in polymers should be developed. For better understanding of the phenomenon of wear, scratch resistance testing can be used. For this project, classic molecular dynamics is used to study the mechanics of nanometer scale scratching on amorphous polymeric materials. As a first approach, a model was created for polyethylene, considering intramolecular and intermolecular interactions as well as mass and volume of the CH2 monomers in a polymer chain. The obtained results include analysis of penetration depth and recovery percentage related to indenter force and size.

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Ding, Yulong. "Numerical simulations of gas-liquid two-phase flow in Polymer Electrolyte Membrane fuel cells". Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42648.

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Water management in PEM fuel cells has received extensive attention for its key role in fuel cell operation. Several water management issues have been identified that needed further investigation, i.e., droplet behaviour on the GDL surface, two-phase flow patterns in gas flow channels, impact of two-phase flow on PEM fuel cell performance, impact of flow mal-distribution on PEM fuel cell performance, and mitigation of flow maldistribution. In this work, those issues were investigated based on simulations using computational fluid dynamics (CFD) method. Using the Volume of Fluid (VOF) two-phase flow model, droplet behaviour and two-phase flow patterns in mini-channels were identified consistently in both simulations and experimental visualizations. The microstructure of the GDL was found to play a significant role in the formation of local two-phase flow patterns, and the wettability of both GDL and channel wall materials greatly impacted on the two-phase flow patterns. A novel 1+3D two-phase flow and reaction model was developed to study the impact of two-phase flow on PEM fuel cell performances. The existence of two-phase flow, especially the slug flow, in gas flow channels was found to be detrimental to the fuel cell performance and stability. Uneven liquid flow distribution into two parallel gas channels significantly reduces the fuel cell output voltage because of the induced severe non-uniform gas distribution, which should be avoided in the operation due to its negative effect on the fuel cell performance and durability. Finally, several maldistribution mitigation methods were tested in the simulation. It was found that utilizing narrow communication channels or adding gas inlet resistances could effectively reduce the gas flow maldistribution.

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Strandberg, Marcus. "Determination and implementation of polymer parameters into simulations of the twin-screw extrusion process". Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-27184.

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This thesis was conducted in cooperation with a Swedish company that develops and manufactures plastic compounds. An increasing need for identifying material properties is seen within the industry in order to predict the outcome of the extrusion process by using simulations. The purpose of this study was to expand a material database with the results obtained through various measurements of the material parameters in order to enable simulations. The numerical descriptions would be analyzed and validated in relation to the obtained results and conducted methods to enable implementation of the material data into the industry. In order to fulfill the purpose, scientific methods was applied by chosen literature studies, research approaches and experimental research. Machine tests were conducted to collect relevant output data that was compared with the results obtained during the simulation process where the experimentally determined material parameters were applied in a material database. Typical injection molding qualities of PET, POM, PC/ABS, SAN and PA66 has been investigated by conducting measurement methods described by standards of the melt flow rate, specific heats, viscosity, crystallinity and melt- and glass transition temperatures. With exception of the viscosity, the material parameters are considered to have high external validity and high reliability and can be implemented into the industry. The bulk- and melt density was determined by adapted methods that need further investigations. The external validity is reduced until these methods and measurements have been validated. The determined material parameters proved to be able to generate reliable simulation results that indicate of how the extrusion process will turn out based on the output values investigated. The data obtained through machine tests was compared with the results that were achieved through simulations and deviated at most 10.9% from the actual outcomes. The viscosity is considered to be the main factor that affects the differences of the output data between the machine tests and the simulation results.

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Trazkovich, Alex. "Effect of Copolymer Sequence on Mechanical Properties of Polymer Nanocomposites from Molecular Dynamics Simulations". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1545930453011375.

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Shen, Kuan-Hsuan. "Modeling ion conduction through salt-doped polymers: Morphology, ion solvation, and ion correlations". The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595422569403378.

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Edvinsson, Tomas. "On the Size and Shape of Polymers and Polymer Complexes : A Computational and Light Scattering Study". Doctoral thesis, Uppsala University, Department of Physical Chemistry, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1930.

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Detailed characterization of size and shape of polymers, and development of methods to elucidate the mechanisms behind shape transitions are central issues in this thesis. In particular we characterize grafted polymer chains under confinement in terms of the chain entanglement complexity and mean molecular size. Confinement of polymers into small regions can drastically affect the structural and mechanical properties, and make these systems convenient for a large number of applications, including the design of lubricants, coatings, and various biotechnical applications.

Using Monte Carlo simulations with a model including both persistence length and intramolecular non-bonded interaction, we find two regimes of polymer behaviour: i) soft mushrooms, where confinement successively flattens the chains with accompanying change in the folding complexity, and ii) hard mushrooms where the compact structures appear to resist confinement and the only way to reorganize the entanglements is by flattening under strong confinement. We also show that a simultaneous use of mean molecular size and chain entanglement complexity renders the possibility to create configurational "phase" diagrams for a wide range of polymers. We have further introduced a new descriptor of folding complexity, the path-space ratio, ζ_α which captures essential features of molecular shape beyond those conveyed by mean size and asphericity.

This thesis also contains results of light scattering measurements on supramolecular complexes formed when mixing an adamantane end-capped star polymer with a β-cyclodextrin polymer. The specific interactions result in an interplay between the association of the end-caps and a strong inclusion interaction between adamantane and β-cyclodextrin.

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Khanal, Kiran. "Liquid-Crystalline Ordering in Semiflexible Polymer Melts and Blends: A Monte Carlo Simulation Study". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1373901748.

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Gollamandala, Deepika Rao. "Brownian dynamic simulations of nanoparticle dispersions in polymer solutions a thesis presented to the faculty of the Graduate School, Tennessee Technological University /". Click to access online, 2009. http://proquest.umi.com/pqdweb?index=13&did=1913184241&SrchMode=1&sid=1&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1265056184&clientId=28564.

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Andreasson, Eskil. "Realistic Package Opening Simulations : An Experimental Mechanics and Physics Based Approach". Licentiate thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00610.

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A finite element modeling strategy targeting package opening simulations is the final goal with this work. The developed simulation model will be used to proactively predict the opening compatibility early in the development process of a new opening device and/or a new packaging material. To be able to create such a model, the focus is to develop a combined and integrated physical/virtual test procedure for mechanical characterization and calibration of thin packaging materials. Furthermore, the governing mechanical properties of the materials involved in the opening performance needs to be identified and quantified with experiments. Different experimental techniques complemented with video recording equipment were refined and utilized during the course of work. An automatic or semi-automatic material model parameter identification process involving video capturing of the deformation process and inverse modeling is proposed for the different packaging material layers. Both an accurate continuum model and a damage material model, used in the simulation model, were translated and extracted from the experimental test results. The results presented show that it is possible to select constitutive material models in conjunction with continuum material damage models, adequately predicting the mechanical behavior of intended failure in thin laminated packaging materials. A thorough material mechanics understanding of individual material layers evolution of microstructure and the micro mechanisms involved in the deformation process is essential for appropriate selection of numerical material models. Finally, with a slight modification of already available techniques and functionalities in the commercial finite element software AbaqusTM it was possible to build the suitable simulation model. To build a realistic simulation model an accurate description of the geometrical features is important. Therefore, advancements within the experimental visualization techniques utilizing a combination of video recording, photoelasticity and Scanning Electron Microscopy (SEM) of the micro structure have enabled extraction of geometries and additional information from ordinary standard experimental tests. Finally, a comparison of the experimental opening and the virtual opening, showed a good correlation with the developed finite element modeling technique. The advantage with the developed modeling approach is that it is possible to modify the material composition of the laminate. Individual material layers can be altered and the mechanical properties, thickness or geometrical shape can be changed. Furthermore, the model is flexible and a new opening device i.e. geometry and load case can easily be adopted in the simulation model. Therefore, this type of simulation model is a useful tool and can be used for decision support early in the concept selection of development projects.

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Sampath, Janani Hall. "Structure-Property Relationships in Model Ionomers from Molecular Dynamics Simulation". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu152543418206124.

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Fischer, Bernd. "Modélisation d'interfaces par simulations numériques : des polymères en solutions à la troposphère". Thesis, Besançon, 2012. http://indexation.univ-fcomte.fr/nuxeo/site/esupversions/e7097b7d-070a-46b8-8034-1b1d5d455974.

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Ce travail a pour objectif de montrer la capacité des simulations numériques à modéliser les phénomènes aux interfaces solides et liquides. Dans le travail sur les interfaces solides, la méthode GCMC a été utilisée pour simuler l'isotherme d'adsorption de !'acétaldéhyde sur la glace dans les conditions de la haute troposphère, puis l'adsorption de composés organiques bi-fonctionnalisés sur la glace a été caractérisée par dynamique moléculaire avec pour objectif d'interpréter des résl1ltats expérimentaux de la littérature. Une partie de ce travail a été consacrée à la circulation du diagramme de phase (p,T) d'aérosols organiques (acide oxalique et malonique) clans les conditions troposphériques afin d'étudier la capacité de ces aérosols à jouer le rôle de noyaux de condensation pour les particules de glace. Le travail sur les interfaces liquides a concerné tout d'abord l'adsorption compétitive de polymères et de smfactants à la surface de l'eau. Il s'appuie sur une description très précise, par simulation, de la structure et de la dynamique de la surface des systèmes considérés. La deuxième partie des travaux sur les interfaces liquides s'est intéressée à la caractérisation du transfert d'ions à travers une interface liquide/liquide par le biais du calcul des variations de l'énergie libre du système au cours du transfc1i. Afin d'obtenir une description très rigoureuse des détails des processus mis enjeu, une méthode spécifique a été développée dans cette thèse pour calculer le profil d'énergie libre en tenant compte directement du caractère très dynamique de l'interface
This work aims to demonstrate the ability of numerical simulations to mode] solid · and liquid interfaces. In the work on the solid interfaces, the GCMC method was used to sin:rnlatc the ads011Jtion isotherrn of acetaldehyde on ice under the conditions of the ·upper tropospherc and the molecular dynamics method was usecl to characterize the adsorption of difünctionalized organic compounds on ice, aiming at interpreting experimental results. Part of this work was devotcd to the simulation of the phase diagrarn (p, T) of organic aerosols (oxalic acid and malonic) in tropospberic conditions to study the ability of aerosols to act as condensation nuclei for icc particlcs. The work: on liquid interfaces concerned firstly the competitive adsorption of polymcrs and surfactants at the water surface. It is based on a very precise desc1iption, by mnncrical simulation, of the structure émd dynamics cif the surface of the considered systems. The second pari of the work on liquid interfaces bas focused on the characterization of ion transfer across a liquid/liquid interface through the calculations of the free energy variations of the system during the transfo·. To obtain a rigorous desc1iptio11 of the details of the corresponding processes, a specific method was developed in this thesis to calculate the free energy profile while taking into account tbe dynamics of the interface

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Grassia, Paul. "Computer simulations of polymer Brownian motion : (with an additional section) The design of an ink jet printer". Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319900.

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