Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Structure And Dynamic Properties Of Interfacially Modified Block Copolymers From Molecular Dynamics Simulations
Download Structure And Dynamic Properties Of Interfacially Modified Block Copolymers From Molecular Dynamics Simulations full books in PDF, epub, and Kindle. Read online Structure And Dynamic Properties Of Interfacially Modified Block Copolymers From Molecular Dynamics Simulations ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Structure and Dynamic Properties of Interfacially Modified Block Copolymers from Molecular Dynamics Simulations by : Youngmi Seo
Download or read book Structure and Dynamic Properties of Interfacially Modified Block Copolymers from Molecular Dynamics Simulations written by Youngmi Seo and published by . This book was released on 2017 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructured diblock copolymers, in which one can take advantage of the different properties of two types of monomers, are of interest in transport applications such as battery electrolytes. One can modify structural properties of diblock copolymers by inserting a midblock with a different composition between the two pure blocks. We study linearly tapered block polymers (TBPs) which are AB diblock copolymers modified by adding a linear gradient region (taper) between the blocks in which composition varies from one species to the other. This gives an additional tuning parameter, the length of the taper, to control the microphase separation behavior, e.g. increased accessibility of the bicontinuous double gyroid phase, or dynamic properties potentially of interest in transport applications. Here, we use molecular dynamics (MD) simulations to investigate both the structural and dynamic properties of TBPs and related block polymer systems. The MD results are consistent with the theoretical results in which the double gyroid network structure is more accessible with a taper and both the effective segregation strength and domain spacing decrease. Interestingly, the inverse TBPs, which have the B-side of the taper bonded to the pure A block, have a significantly shorter domain spacing compared to the normal TBPs. This is related to the polymer conformations; in contrast to typical diblocks or normal TBPs, inverse tapered chains can exist in several distinct conformations. For instance, inverse tapered chains may fold back and forth across the interface, bridge between multiple domains, or stretch over two layers of lamellae depending on the taper length. This conformational behavior was quantitatively analyzed as a function of the taper length. Theoretical work had predicted that the 50% inverse TBPs have a unique phase diagram; the larger of the two pure end blocks can phase separate into double gyroid phases. The MD results also show such a double gyroid structure for the 50% inverse TBPs. To understand the potential impact of tapers on ion dynamics, we investigated the diffusion of a small amount of penetrants in both normal and inverse TBPs. We considered uncharged monomer-sized penetrants, which have favorable interactions with A monomers of a strength that is chosen to make an analogy with the solvation of ions in the higher dielectric microphase of certain experimentally relevant copolymers. With normal tapering, both polymer and penetrant diffusion parallel to the lamellae increases as taper length increases, but inverse tapers show a non-monotonic variation in polymer diffusion. This is explained by analyzing differences in dynamic behavior between inverse tapered polymers with different types of conformations. However, regardless of the type of the midblocks, the penetrants’ diffusion constant values generally collapsed on a single curve when plotted against blockiness (average block length as a fraction of chain length) or number of A-B bonds per chain which can represent the degree of local A-B mixing. This implies that the local A-B mixing of monomers (rather than polymer conformation) is the most important factor in determining penetrant diffusion. These insights may allow improved design of nanostructured membranes for small molecule transport.
Book Synopsis Molecular Dynamics Simulations of Amphiphilic Macromolecules at Interfaces by : Selina Nawaz
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.
Book Synopsis Block Copolymers by : Nikos Hadjichristidis
Download or read book Block Copolymers written by Nikos Hadjichristidis and published by John Wiley & Sons. This book was released on 2003-04-28 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers may be classified as either homopolymers, consisting of one single repeating unit, or copolymers, consisting of two or more distinct repeating units. Block copolymers contain long contiguous blocks of two or more repeating units in the same polymer chain. Covering one of the hottest topics in polymer chemistry, Block Copolymers provides a coherent overview of the synthetic routes, physical properties, and applications of block copolymers. This pioneering text provides not only a guideline for developing synthetic strategies for creating block copolymers with defined characteristics, but also a key to the relationship between the physical properties of block copolymers and the structure and dynamics of materials. Covering features of the chemistry and physics of block copolymers that are not found in comparable texts, Block Copolymers illustrates the structure-activity relationship of block copolymers and offers suggestions for the design of specific applications. Divided into five sections-Block Copolymers includes chapters on: * Block Copolymers by Chemical Modification of Precursor Polymers * Nonlinear Block Copolymers * Adsorption of Block Copolymers at Solid-Liquid Interfaces * Theory of Block Copolymer Segregation * Phase Transformation Kinetics * Block Copolymer Morphology * Block Copolymer Dynamics Polymer chemists, physicists, chemical engineers, and materials scientists, as well as graduate students in polymer science, will find Block Copolymers to be an invaluable text.
Book Synopsis Block Copolymers by : Francisco Balta Calleja
Download or read book Block Copolymers written by Francisco Balta Calleja and published by CRC Press. This book was released on 2000-06-09 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt: A summary of block copolymer chemical structures and synthesis. It discusses physical methods of characterization such as computer simulation, microhardness, dielectric spectroscopy, thermal mechanical relaxation, ultrasonic characterization, transmission electron microscopy, X-ray scattering, and NMR, among others. It also outlines rheological and processing parameters in the multiphase polymer systems with stable microstructures.
Book Synopsis Processing, Structure and Properties of Block Copolymers by : M.J. Folkes
Download or read book Processing, Structure and Properties of Block Copolymers written by M.J. Folkes and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers represent an important class of multi-phase material, which have received very widespread attention, particularly since their successful commercial development in the mid-1960s. Much of the interest in these polymers has arisen because of their rather remarkable micro phase morphology and, hence, they have been the subject of extensive microstructural examination. In many respects, the quest for a comprehensive interpretation of their structure, both theoretically and experimentally, has not been generally matched by a corresponding enthusiasm for developing structure/property relationships in the context of their commercial application. Indeed, it has been left largely to the industrial companies involved in the development and utilization of these materials to fulfil this latter role. While it is generally disappointing that a much greater synergism does not exist between science and technology, it is especially sad in the case of block copolymers. Thus these materials offer an almost unique opportunity for the application of fundamental structural and property data to the interpretation of the properties of generally processed artefacts. Accordingly, in this book, the editor has drawn together an eminent group of research workers, with the specific intention of highlighting some of those aspects of the science and technology of block copolymers that are potentially important if further advances are to be made either in material formulation or utilization. For example, special consideration is given to the relationship between the flow properties of block copo lymers and their microstructure.
Book Synopsis Publications of the National Institute of Standards and Technology ... Catalog by : National Institute of Standards and Technology (U.S.)
Download or read book Publications of the National Institute of Standards and Technology ... Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1994 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Structure and Molecular Dynamics of Liquid Crystalline, Isotropic Block Copolymers by : Rosina Rentenberger
Download or read book Structure and Molecular Dynamics of Liquid Crystalline, Isotropic Block Copolymers written by Rosina Rentenberger and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Study the Interaction Mechanisms of Block Copolymers with Biological Interfaces by : Samira Hezaveh
Download or read book Study the Interaction Mechanisms of Block Copolymers with Biological Interfaces written by Samira Hezaveh and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polyethylene oxide (PEO) and polypropylene oxide (PPO) homopolymers as well as the block copolymers based on them (also called Pluronics) have many applications in biotechnology (e.g. detergent, lubrication, emulsification) and in biomedical sciences (e.g. drug delivery, biocompatible materials). This versatility is a consequence of their peculiar properties in solution and at interfaces. However, despite the large number of the available experimental data, still the molecular mechanism of their interactions with biological systems remains elusive. Fortunately, computational material science is now coming to an age of providing power tools to explore these phenomena with highly realistic accuracy. So far, this is one of the best approaches to study these systems but the application in the direction to explore the interaction of polymers with biological interface is still in its infancy. The research work in this PhD thesis aimed to use the most advanced tool of computational material science to study these polymers in solution and their interactions with biological membranes. The study of these phenomena was conducted using Molecular Dynamics simulations at multiscale level that allowed exploring these systems on scale of different order of magnitude in length and time. For this purpose, atomistic and coarse-grained models of the polymers based on the GROMOS/OPLS and MARTINI force fields respectively have been developed. Using atomistic models, different thermodynamic, dynamic and structural properties of the polymers were studied and compared with the available experimental data. The MARTINI coarse-grained model was then used to study the interaction of the Pluronics F38, P85 an L64 with DMPC lipid bilayer. The results were strongly support the experimental findings. Finally, using a recently proposed and developed Self Consistent density Field (SCF) method, simulation studies of Pluronics micelles formation and their interaction with DPPC lipid bilayers were accomplished. The results of these simulations evidenced a possible scenario of micelle dissolution at the bilayer surface that consists in a progressive diffusion of single Pluronic chains in contact with the interface from the micelle into the bilayer.
Book Synopsis A Modern Course in Transport Phenomena by : David C. Venerus
Download or read book A Modern Course in Transport Phenomena written by David C. Venerus and published by Cambridge University Press. This book was released on 2018-03-15 with total page 537 pages. Available in PDF, EPUB and Kindle. Book excerpt: Integrating nonequilibrium thermodynamics and kinetic theory, this unique text presents a novel approach to the subject of transport phenomena.
Book Synopsis Effect of Copolymer Sequence on Mechanical Properties of Polymer Nanocomposites from Molecular Dynamics Simulations by : Alex Trazkovich
Download or read book Effect of Copolymer Sequence on Mechanical Properties of Polymer Nanocomposites from Molecular Dynamics Simulations written by Alex Trazkovich and published by . This book was released on 2019 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: When incorporated into polymers, nanoparticles are known to modify the structure and dynamics of nearby polymer chains. Because nanoparticles have a high surface area to volume ratio, the properties of the polymer-nanoparticle interphase region can have a significant effect on the overall composite properties even at relatively low nanoparticle loading. In this work, we study the polymer-nanoparticle interphase region using molecular dynamics simulations, and we analyze the impact of a nanoparticle on local structure, dynamics, and viscoelastic properties. Of particular interest here is a class of systems which consists of nanoparticles incorporated into two-component copolymers where one component of the copolymer interacts more favorably with the nanoparticle than the other. In these systems, modifying the particular copolymer sequence may modify the interphase properties, and composite properties may therefore be adjusted even while maintaining the same overall monomer ratio. These systems have been the subject of several simulation studies focused on nanoparticle dispersion and assembly; however, relatively little simulation work has focused specifically on the impact of copolymer sequence on properties of the copolymer-nanoparticle interphase.
Book Synopsis Structure and Molecular Dynamics of Liquid Crystalline by : Rosina Staneva
Download or read book Structure and Molecular Dynamics of Liquid Crystalline written by Rosina Staneva and published by . This book was released on 2006 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Time-dependent Morphologies and Viscoelastic Properties of Block Copolymers by : Jeffrey Carl Kelterborn
Download or read book Time-dependent Morphologies and Viscoelastic Properties of Block Copolymers written by Jeffrey Carl Kelterborn and published by . This book was released on 1981 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic mechanical properties of block copolymers over a wide temperature range have been previously correlated with the phase-separated microstructure of these systems. In the present work the morphology of the block copolymer is altered by large tensile deformation at various temperatures. Upon removal of the applied stress the morphological features of such stretched-and-released systems become functions of time, as the non-equilibrium microstructure reverts to a thermodynamically stable state. This reformation process is monitored by dynamic mechanical measurements with a modified torsion pendulum capable of applying both tensile and torsional deformation. Experimental results are analyzed using a modified Nielsen model to obtain information on the time-dependent structural state of the samples. These results are then compared with stress-strain curves to provide further insight into the structure breakdown-reformation mechanisms. Two competing mechanisms, domain fracture and block pull out, are proposed to explain these experimental observations. (Author).
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Engineering Progress written by and published by . This book was released on 2008 with total page 718 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Molecular Thermodynamics of Complex Systems by : Xiaohua Lu
Download or read book Molecular Thermodynamics of Complex Systems written by Xiaohua Lu and published by Springer Science & Business Media. This book was released on 2009 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Molecular Thermodynamics of Complex Systems, the chapter authors critically examine not only the current state of the art in chemical research into structure and bonding, but also look at the direction the subject might take as it develops in future years.
Book Synopsis Interface / Interphase in Polymer Nanocomposites by : Anil N. Netravali
Download or read book Interface / Interphase in Polymer Nanocomposites written by Anil N. Netravali and published by John Wiley & Sons. This book was released on 2016-11-29 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant research has been done in polymeric nanocomposites and progress has been made in understanding nanofiller-polymer interface and interphase and their relation to nanocomposite properties. However, the information is scattered in many different publication media. This is the first book that consolidates the current knowledge on understanding, characterization and tailoring interfacial interactions between nanofillers and polymers by bringing together leading researchers and experts in this field to present their cutting edge research. Eleven chapters authored by senior subject specialists cover topics including: Thermodynamic mechanisms governing nanofiller dispersion, engineering of interphase with nanofillers Role of interphase in governing the mechanical, electrical, thermal and other functional properties of nanocomposites, characterization and modelling of the interphase Effects of crystallization on the interface, chemical and physical techniques for surface modification of nanocellulose reinforcements Electro-micromechanical and nanoindentation techniques for interface evaluation, molecular dynamics (MD) simulations to quantify filler-matrix adhesion and nanocomposite mechanical properties.
Book Synopsis Simulation Methods for Polymers by : Michael Kotelyanskii
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:
