Macromolecular Theory and Simulations

Cover image for Vol. 24 Issue 3

Early View (Online Version of Record published before inclusion in an issue)

Editor-in-Chief: Kirsten Severing, Editor: Stefan Spiegel

Online ISSN: 1521-3919

Associated Title(s): Macromolecular Chemistry and Physics, Macromolecular Materials and Engineering, Macromolecular Rapid Communications, Macromolecular Reaction Engineering

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  1. Communications

    1. Azeotropic Equilibrium Copolymerization

      Ryszard Szymanski

      Article first published online: 29 JUN 2015 | DOI: 10.1002/mats.201500034

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      Reversible copolymerization can behave azeotropically only when certain relationships, given in the paper, between the equilibrium and rate constants of homo- and cross-propagations are held. The main conditions for azeotropicity of the reversible copolymerization ensure that the compositions and microstructures of initially formed copolymer and of that at the system equilibrium are identical.

  2. Full Papers

    1. Systematic Coarse Graining of a High-Performance Polyimide

      Sudharsan Pandiyan, Priya V. Parandekar, Om Prakash, Thomas K. Tsotsis and Sumit Basu

      Article first published online: 19 JUN 2015 | DOI: 10.1002/mats.201500009

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      The figure shows three mapping schemes of molecular fragments in the backbone of the commercial polyimide HFPE-30. A coarse-grained representation with large number of beads is necessary to predict static and configurational properties. However, with smaller number of beads and an appropriate amount of friction on the beads, we are able to predict glass transition temperature and stress–strain response.

    2. Hierarchical Microstructures Self-Assembled from Linear Multiblock Copolymers in Thin Films

      Jingyuan Lin, Shuting Gong, Xu Zhang and Liquan Wang

      Article first published online: 16 JUN 2015 | DOI: 10.1002/mats.201500031

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      In thin films of linear multiblock copolymers, not only the period of large- and small-length-scale lamellae but also the orientation of small-length-scale lamellae can be tuned by varying film thickness. Moreover, a reentrant phase transition of perpendicular lamellae-in-lamellae with increasing the film thickness is revealed.

    3. Monte Carlo Simulation Studies of Regular and Irregular Dendritic Polymers

      Edyta Wawrzyńska, Andrzej Sikorski and Gerhard Zifferer

      Article first published online: 8 JUN 2015 | DOI: 10.1002/mats.201500036

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      Regular and irregular dendritic polymers, the latter realized for several types of branch-length distributions, are simulated and their properties are compared. In addition, for the regular case emphasis is given to parameters in the limit of infinite branch length (spacer length) in order to obtain model independent results.

    4. Parallel Monte Carlo Simulation of Molecular Weight Distribution and Chemical Composition Distribution for Copolymerization on a Graphics Processing Unit Platform

      Jinzu Weng, Xi Chen, Zhen Yao and Lorenz T. Biegler

      Article first published online: 3 JUN 2015 | DOI: 10.1002/mats.201500021

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      Monte Carlo method is suitable to simulate the microstructural distributions, but it normally requires a long time for the computation. By decomposing the conventional Monte Carlo simulation of all chains into millions of threads, the calculation is parallelized on a GPU platform and more than 30-fold speedup ratio is obtained.

    5. Direct Equilibration and Characterization of Polymer Melts for Computer Simulations

      Livia A. Moreira, Guojie Zhang, Franziska Müller, Torsten Stuehn and Kurt Kremer

      Article first published online: 3 JUN 2015 | DOI: 10.1002/mats.201500013

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      Excluded volume and topological constraints (entanglements) lead to difficulties for polymer melt equilibration in computer simulations. To avoid long equilibration runs, an improved feedback loop methodology is introduced, which only needs relaxation on short length scales. The analysis shows that a homogeneous density and perfect internal distances along the chain backbone can be reached for melts of chains of up to about 45 entanglement lengths.

    6. A Study of HCl Gas Adsorption/Desorption Properties of PNIPAM Brushes

      Xin Jun Zhao, Zhi Fu Gao and Zhong Ying Jiang

      Article first published online: 3 JUN 2015 | DOI: 10.1002/mats.201500027

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      HCl gas adsorption capacity of poly(N-isopropylacrylamide) (PNIPAM) brushes is described by PNIPAM–HCl hydrogen bonds. Hydrogen bonding becomes a key element in determining HCl adsorption/desorption behaviors of PNIPAM brushes. The morphology of PNIPAM brushes may have a significant effect on the HCl adsorption/desorption properties.

    7. Coarse-Grained and Atomistic Simulations for the G = 4 PAMAM-EDA Dendrimer

      Juan J. Freire, Ana M. Rubio and Carl McBride

      Article first published online: 1 JUN 2015 | DOI: 10.1002/mats.201500028

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      Extended molecular dynamics simulations for protonated and neutral G = 4 PAMAM-EDA in water permit an accurate analysis of conformational properties. The trajectories are used to compute binary interactions between dendrimer molecules. These interactions are shown to obey the theoretically predicted Gaussian behavior.

    8. Theoretical Consideration of Phase Behavior of the Products of Free-Radical Copolymerization Described by the Penultimate Model

      Semion I. Kuchanov, Artem N. Bogdanov and Konstantin V. Tarasevich

      Article first published online: 26 MAY 2015 | DOI: 10.1002/mats.201500022

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      Finding of the dependence of the phase behavior of heteropolymer liquids on the chemical structure of their macromolecules is of utmost importance. Theoretical consideration of such a behavior of multiblock copolymers whose architectures are describable by the extended Markov chain has been undertaken in this paper. Our analysis reveals the possibility of the existence in their melts of phase diagrams of nontraditional appearance.

    9. Computational Investigations of Arginine-Rich Peptides Interacting with Lipid Membranes

      Juan-mei Hu, Wen-de Tian and Yu-qiang Ma

      Article first published online: 21 MAY 2015 | DOI: 10.1002/mats.201500023

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      The translocation of hexa-arginine peptides across membrane is investigated by computer simulations. It is found the translocation efficiency of the bundled peptides is much higher than that of the random case. Further, the primary role of the hydrophobic group of peptide amphiphiles is facilitating the formation of aggregation for improving their penetration efficiency. We propose that peptides with high charge density and proper hydrophobic tails will be the candidates in designing drug carriers.

    10. Vesicle-Like Globules of Amphiphilic Macromolecules

      Anna A. Glagoleva, Valentina V. Vasilevskaya and Alexei R. Khokhlov

      Article first published online: 19 MAY 2015 | DOI: 10.1002/mats.201500024

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      Spontaneous formation of a vesicle-like capsule by a collapsed macromolecule with amphiphilic monomer units is demonstrated for the first time by means of molecular dynamics computer simulation. Such vesicle-like globules are formed by long macromolecules with solvophilic backbone and short solvophobic side groups and could be prospective for practical applications as nanocapsules and nanocarriers.

  3. Communications

    1. A Baseline Model for the Simulation of Polyurethane Foams via the Population Balance Equation

      Mohsen Karimi and Daniele L. Marchisio

      Article first published online: 19 MAY 2015 | DOI: 10.1002/mats.201500014

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      This manuscript describes a new mathematical model for the simulation of polyurethane foams, which for the first time employs a population balance model for describing the evolution of the bubble (or cell) size distribution of the foam. The model is here validated against experiments from the literature and will be further developed in our future work.

  4. Full Papers

    1. Exact Analytical Solution for Large-Amplitude Oscillatory Shear Flow

      Chaimongkol Saengow, Alan Jeffrey Giacomin and Chanyut Kolitawong

      Article first published online: 18 MAY 2015 | DOI: 10.1002/mats.201400104

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      We derive the first exact analytical solution for the extra stress tensor in LAOS flow for both the normal stress differences and the shear stress responses. Our exact solution agrees with the measured behaviors for three molten plastics, not only for alternance, but also for startup.

    2. Quantum Mechanical Computations and Microkinetic Modeling to Obtain Mechanism and Kinetics of Oxidative Degradation of a Polyimide

      Sooraj Kunnikuruvan, Priya V. Parandekar, Om Prakash, Thomas K. Tsotsis, Sumit Basu and Nisanth N. Nair

      Article first published online: 5 MAY 2015 | DOI: 10.1002/mats.201500019

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      Quantum mechanical calculations combined with microkinetic analysis are used to explore the oxidative degradation of a commercially important polyimide, PMR-15, at high temperatures. The most vulnerable moiety of this polyimide and the rate determining step of the oxidative degradation are scrutinized. Possible modifications on PMR-15 to improve its thermo-oxidative stability are thereby proposed.

  5. Full Paper

    1. Temperature Dependence of Structural Properties and Chain Configurational Study: A Molecular Dynamics Simulation of Polyethylene Chains

      Haifeng Lu, Zhiping Zhou, Tongfan Hao, Xubo Ye and Yijing Ne

      Article first published online: 3 APR 2015 | DOI: 10.1002/mats.201500007

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      Micro-structural evolution of polyethylene across the glass transition temperature is investigated by full atom molecular dynamic simulation. The relationship between the specific volume and the temperature can be used to determine glass temperature of amorphous polyethylene system. The dihedral distribution of the overall bonds of the amorphous polyethylene chain system keeps consistent with the rotational isomeric state scheme. The dependence of isomer probability of skeletal bonds and average radius of gyration on temperature also can be used to estimate the glass temperature.

  6. Full Papers

    1. Analysis of Advective–Diffusive Transport in Complex Mixing Devices by the Diffusive Mapping Method

      Oleksandr Gorodetskyi, Iaroslav Vivat, Michel F. M. Speetjens and Patrick D. Anderson

      Article first published online: 1 APR 2015 | DOI: 10.1002/mats.201400083

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      Mixing in realistic industrial devices is of great relevance. The diffusive mapping method is a flexible technique for mixing simulations inside complex geometries. This study applies this method to advective–diffusive transport in two prototypical 3D industrial mixers. It is combined with the extended finite element method (XFEM), enabling reliable and efficient computation of evolving concentration fields.

  7. Communications

    1. New Structural Model of PANI/CSA Conducting Polymer System Obtained by Molecular Dynamics Simulations

      Maciej Śniechowski, Remigiusz Borek, Konrad Piwowarczyk and Wojciech Łużny

      Article first published online: 31 MAR 2015 | DOI: 10.1002/mats.201400105

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      The structure of polyaniline protonated with camphorsulfonic acid has been modeled by molecular dynamics simulations. All partial charges have been derived from DFT quantum calculations and a new force field has been applied. The resulting stable structure is characterized by double layers of PANI separated by double layers of CSA. The new model is in good agreement with several experimental data.

  8. Full Papers

    1. Realistic Representation of Kinetics and Microstructure Development During Chain Shuttling Polymerization of Olefin Block Copolymers

      Mostafa Ahmadi and Amin Nasresfahani

      Article first published online: 25 MAR 2015 | DOI: 10.1002/mats.201500004

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      An effective model is developed for representation of kinetics and microstructure evolution in the course of chain shuttling polymerization in the view of both OBC chains and individual hard and soft blocks.

    2. Modeling of Branching Distributions in Butyl Acrylate Polymerization Applying Monte Carlo Methods

      Marco Drache, Benjamin Hosemann, Tetyana Laba and Sabine Beuermann

      Article first published online: 23 FEB 2015 | DOI: 10.1002/mats.201400081

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      The Monte Carlo (MC) simulator mcPolymer is capable of handling of a large number of molecules, allowing for the implementation of a chain-length-dependent termination model. It was applied to the complex kinetic model of butyl acrylate polymerizations, being able to reproduce experimental findings. Furthermore, detailed information on the microstructure of each individual polymer chain was extracted.

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