Download or read book Atomistic Computer Simulations of the Molecular Structure Thermodynamics and Dynamics of Glassy Polymers at Interfaces written by Kevin Francis Mansfield and published by . This book was released on 1991 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Atomistic Simulation of Structural and Dynamic Differences in Glassy and Liquid States of Atactic Poly Propylene written by and published by . This book was released on 1989 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomistic simulation techniques, in conjunction with experimental and theoretical approaches, have proven themselves to be useful tools for the study of materials. Recent years have seen the first application of a variety of simulation methods to investigating the phenomena occurring in bulk polymers. Among these, possibly the most important and challenging is the glass transition. Despite its significance, the glass transition is still poorly characterized except in a phenomenological manner. For instance, comprehension of how the structure of a polymer glass differs from that of the liquid is limited to the somewhat vaguely defined concept of free volume. It is not known how the volume associated with atoms might be distributed within the polymer or how changes in the distribution are related to the property changes seen at the glass transition. In addition, what other structural changes occur on passing between the liquid and glass states are not known. These questions involve the local atomic level structure and motion of individual or small groups of atoms. Available experimental and theoretical methods are not well suited to investigate these details. Therefore, simulation is the only way to obtain physical insight into these problems at the present time. Reported here are initial results obtained from a series of such computer simulations carried out on a simple vinyl polymer, atactic poly(propylene). Keywords: Computer simulation; Structural relaxations in glassy polymers; Glass transition; Molecular structure; Molecular interactions; Transition phases.
Download or read book Molecular Dynamics of Glass Forming Systems written by George Floudas and published by Springer Science & Business Media. This book was released on 2010-11-25 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pressure is one of the essential thermodynamic variables that, due to some former experimental difficulties, was long known as the “forgotten variable.” But this has changed over the last decade. This book includes the most essential first experiments from the 1960's and reviews the progress made in understanding glass formation with the application of pressure in the last ten years. The systems include amorphous polymers and glass-forming liquids, polypeptides and polymer blends. The thermodynamics of these systems, the relation of the structural relaxation to the chemical specificity, and their present and future potential applications are discussed in detail. The book provides (a) an overview of systems exhibiting glassy behavior in relation to their molecular structure and provides readers with the current state of knowledge on the liquid-to-glass transformation, (b) emphasizes the relation between thermodynamic state and dynamic response and (c) shows that the information on the pressure effects on dynamics can be employed in the design of materials for particular applications. It is meant to serve as an advanced introductory book for scientists and graduate students working or planning to work with dynamics. Several scientific papers dealing with the effects of pressure on dynamics have appeared in leading journals in the fields of physics in the last ten years. The book provides researchers and students new to the field with an overview of the knowledge that has been gained in a coherent and comprehensive way.
Download or read book Molecular Interfacial Phenomena of Polymers and Biopolymers written by P Chen and published by Taylor & Francis US. This book was released on 2005-07-22 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book combines three fundamental areas of interest to the science and engineering community, these being material science, nanotechnology and molecular engineering. Although there have been various results published in this field, there has yet to be a fully comprehensive review. This book covers key research on molecular mechanisms and thermodynamic behaviour of (bio)polymer surfaces and interfaces, from theoretical and experimental perspectives.
Download or read book Engineered Materials Abstracts written by and published by . This book was released on 1992-05 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Ordering Structure and Dynamics of Conjugated Polymers at Interfaces Multiscale Molecular Dynamics Simulations written by Yeneneh Yalew Yimer and published by . This book was released on 2014 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer-based solar cells (PSCs) require significant improvements in efficiency and life time in order to be commercially viable. Interfacial structure and morphology dictate the performance of PSCs, and these properties in turn depend on processing conditions and surface chemistry. To optimize device performance, detailed knowledge of the factors most critical to the molecular-level structure, morphology and dynamics of donor/acceptor systems at interfaces will be necessary. For one promising donor, poly(3-hexylthiophene (P3HT), we have utilized all-atom and coarse-grained molecular dynamics simulations to investigate such properties at liquid/vacuum, solid/liquid and solid/solid interfaces. At liquid/vacuum interfaces, static and dynamic properties of P3HT films and their dependence on temperature and molecular weight were studied. P3HT chains showed ordering through preferential exposure of side-chain at the interface, and surface tension showed strong dependence on temperature and molecular weight. Properties such as self-diffusion coefficients, chain end-to-end distance and torsion autocorrelations were also utilized to quantify the dynamics of the P3HT chains in the film. Both static and dynamic properties of P3HT were found to be in agreement with well-known models for polymers.Subsequent simulations of P3HT/water systems offered insight into the wetting behavior of P3HT and the nature of the solid-liquid interface in crystalline and amorphous P3HT. From contact angle calculations, different P3HT surfaces were determined to be hydrophobic. In the time scale of our simulations, no observable change in the orientation of the P3HT at interfaces was observed.Furthermore, the molecular ordering of P3HT close to substrates is expected to be the key to device performance. Ordering of P3HT chains at the interface can be tuned by altering the substrate surface chemistry. We investigated the effect of surface chemistry on the ordering of P3HT on self-assembled monolayers (SAMs) of n-alkanethiols. The results showed that the ordering of P3HT strongly depends on the P3HT-SAM interactions. The effect of solvent on the P3HT-SAM interactions was also studied. In addition, we characterized the surface properties of pure SAMs on gold 111. The end-functionalized network structure was found to be correlated to the adsorption sites. For P3HT/acceptor systems, all-atom simulations are challenging because of the need to access large spatial and temporal regimes. To overcome this, we developed a coarse-grained model for P3HT based on the all-atom force field. The coarse-grained model showed good agreement with bulk and interfacial properties obtained from the all-atom model and has a great potential for analyzing morphology and dynamics of P3HT/acceptor blends.
Download or read book Molecular Dynamics Simulations of Amphiphilic Macromolecules at Interfaces written by Selina Nawaz and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this thesis is to investigate the structural and thermodynamic properties of biologically and technological relevant macromolecules when placed at soft interfaces. In particular two amphiphilic macromolecules characterized by different topologies have been investigated namely amphiphilic dendrimers and linear block copolymers. This goal is achieved using a multiscale approach which includes all-atom, united atom and coarse grained models by means of molecular dynamic simulations. Amphiphilic dendrimers have shown to be promising building blocks for a range of interfacial materials and can be used in applications such as surface-base sensors or surface nanopatterning. In this part of the thesis by means of all-atom molecular dynamics simulations, we investigated the structure and stability of alkyl-modified polyamido-amide (PAMAM) dendrimers at the air/water interface as a function of the number and the relative position of the modified end groups. We found that the PAMAM dendrimer with all terminal groups functionalized is more stable at the interface than the Janus dendrimer, where only half the amine groups are modified. These results indicate that monolayers of fully functionalized molecules could be as stable as (or more stable than) those self-assembled from Janus molecules. The second part of the thesis is devoted to model a particular family of amphiphilic triblock copolymer sold as Pluronics, consisting of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) arranged as PEO-PPO-PEO. There is evidence that this class of amphiphilic materials can be used for different biological applications. A fuller understanding of the molecular mechanisms underpinning their interactions with living cells is essential for ensuring the polymers safety and efficacy in biomedical applications. Using united-atom molecular dynamics simulations and membrane lysis assays, we investigated the relationship between the molecular conformations of a subset of the Pluronic copolymers (L31, L61, L62 and L64) and their haemolytic activity. Our computational studies suggest that the hydrophilic blocks in these copolymers interact with the polar head groups of lipid molecules, resulting in a predicted modification of the structure of the membranes. Parallel membrane lysis assays in human erythrocytes indicate differences in the rates of haemolysis, as a result of incubation with these polymers, which correlate well with the predicted interactions from the atomistic simulations. The computational data thus provide a putative mechanism to rationalize the available experimental data on membrane lysis by these copolymers. The data quantitatively agree with haemoglobin release endpoints measured when copolymers with the same molecular weight and structure as of those modelled are incubated with erythrocytes. The data further suggest some new structure- function relationships at the nanoscale that are likely to be of importance in determining the biological activity of these otherwise inert copolymers. In order to visualise the effect of Pluronics at a length and time scale closer to the experimental one, in the third part of the thesis we developed a coarse-grained model for the amphiphilic copolymers within the framework of the MARTINI forcefield (Marrink et al., J. Phys. Chem. B, 2007, 111, 7812). The MARTINI force field is usually parameterized targeting thermodynamic properties. In addition to this, we further parameterized it based on atomistic simulations validating the parameters against structural properties of the copolymers. The ability of the model to predict several structural and thermodynamic properties of the atomistic system have been explored. The aim of this work is to be able to simulate the polymer/lipid interface at polymer concentration similar to the experimental one.
Download or read book ACS Directory of Graduate Research 1993 written by American Chemical Society. Committee on Professional Training and published by . This book was released on 1993 with total page 1700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation Methods for Polymers written by Michael Kotelyanskii and published by CRC Press. This book was released on 2004-03-01 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomistic Modeling of Physical Properties written by Lucien Monnerie and published by Springer. This book was released on 1994-07-22 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions by: R.H. Boyd; B.G. Sumpter, D.W. Noid, G.L. Liang, B. Wunderlich; M.D. Ediger, D.B. Adolf; R.-J. Roe; I. Bahar, B. Erman, L. Monnerie; A.A. Gusev, F. Müller-Plathe, W.F. van Gunsteren, U.W. Suter; L.R. Dodd, D.N. Theodorou; E. Leontidis, J.J. de Pablo, M. Laso, U.W. Suter; K.S. Schweizer.
Download or read book Monte Carlo and Molecular Dynamics Simulations in Polymer Science written by Kurt Binder and published by Oxford University Press. This book was released on 1995-08-03 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by leading experts from around the world, Monte Carlo and Molecular Dynamics Simulations in Polymer Science comprehensively reviews the latest simulation techniques for macromolecular materials. Focusing in particular on numerous new techniques, the book offers authoritative introductions to solutions of neutral polymers and polyelectrolytes; dynamics of polymer melts, rubbers and gels, and glassy materials; thermodynamics of polymer mixing and mesophase formation, and polymers confined at interfaces and grafted to walls. Throughout, contributors offer practical advice on how to overcome the unique challenges posed by the large size and slow relaxation of polymer coils. Students and researchers in polymer chemistry, polymer physics, chemical engineering, and materials and computational science will all benefit from the cogent, step-by-step introductions contained in this important new book.
Download or read book Modeling and Simulation in Polymers written by Purushottam D. Gujrati and published by John Wiley & Sons. This book was released on 2010-03-30 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling a gap in the literature and all set to become the standard in this field, this monograph begins with a look at computational viscoelastic fluid mechanics and studies of turbulent flows of dilute polymer solutions. It then goes on discuss simulations of nanocomposites, polymerization kinetics, computational approaches for polymers and modeling polyelectrolytes. Further sections deal with tire optimization, irreversible phenomena in polymers, the hydrodynamics of artificial and bacterial flagella as well as modeling and simulation in liquid crystals. The result is invaluable reading for polymer and theoretical chemists, chemists in industry, materials scientists and plastics technologists.
Download or read book Polymer Science and Engineering written by National Research Council and published by National Academies Press. This book was released on 1994-01-01 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers are used in everything from nylon stockings to commercial aircraft to artificial heart valves, and they have a key role in addressing international competitiveness and other national issues. Polymer Science and Engineering explores the universe of polymers, describing their properties and wide-ranging potential, and presents the state of the science, with a hard look at downward trends in research support. Leading experts offer findings, recommendations, and research directions. Lively vignettes provide snapshots of polymers in everyday applications. The volume includes an overview of the use of polymers in such fields as medicine and biotechnology, information and communication, housing and construction, energy and transportation, national defense, and environmental protection. The committee looks at the various classes of polymersâ€"plastics, fibers, composites, and other materials, as well as polymers used as membranes and coatingsâ€"and how their composition and specific methods of processing result in unparalleled usefulness. The reader can also learn the science behind the technology, including efforts to model polymer synthesis after nature's methods, and breakthroughs in characterizing polymer properties needed for twenty-first-century applications. This informative volume will be important to chemists, engineers, materials scientists, researchers, industrialists, and policymakers interested in the role of polymers, as well as to science and engineering educators and students.
Download or read book Computational Soft Matter from Synthetic Polymers to Proteins written by Norbert Attig and published by . This book was released on 2004 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recent Advances in Carbon Capture and Storage written by Yongseung Yun and published by BoD – Books on Demand. This book was released on 2017-03-08 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon capture and storage (CCS) has been considered as a practical way in sequestering the huge anthropogenic CO2 amount with a reasonable cost until a more pragmatic solution appears. The CCS can work as a bridge before fulfilling the no-CO2 era of the future by applying to large-scale CO2 emitting facilities. But CCS appears to lose some passion by the lack of progress in technical developments and in commercial success stories other than EOR. This is the time to go back to basics, starting from finding a solution in small steps. The CCS technology desperately needs far newer ideas and breakthroughs that can overcome earlier attempts through improving, modifying, and switching the known principles. This book tries to give some insight into developing an urgently needed technical breakthrough through the recent advances in CCS research, in addition to the available small steps like soil carbon sequestration. This book provides the fundamental and practical information for researchers and graduate students who want to review the current technical status and to bring in new ideas to the conventional CCS technologies.
Download or read book The Art of Molecular Dynamics Simulation written by D. C. Rapaport and published by Cambridge University Press. This book was released on 2004-04 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: First time paperback of successful physics monograph. Copyright © Libri GmbH. All rights reserved.
Download or read book Maro Polymer Notes written by and published by . This book was released on 1997 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:
