1
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Zhang J, Lei J, Feng P, Floudas G, Zhang G, Zhou J. Capillary filling of star polymer melts in nanopores. J Chem Phys 2024; 160:054903. [PMID: 38341697 DOI: 10.1063/5.0188955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 01/15/2024] [Indexed: 02/13/2024] Open
Abstract
The topology of a polymer profoundly influences its behavior. However, its effect on imbibition dynamics remains poorly understood. In the present work, capillary filling (during imbibition and following full imbibition) of star polymer melts was investigated by molecular dynamics simulations with a coarse-grained model. The reversal of imbibition dynamics observed for linear-chain systems was also present for star polymers. Star polymers with short arms penetrate slower than the prediction of the Lucas-Washburn equation, while systems with long arms penetrate faster. The radius of gyration increases during confined flow, indicating the orientation and disentanglement of arms. In addition, the higher the functionality of the star polymer, the more entanglement points are retained. Besides, a stiff region near the core segments of the stars is observed, which increases in size with functionality. The proportion of different configurations of the arms (e.g., loops, trains, tails) changes dramatically with the arm length and degree of confinement but is only influenced by the functionality when the arms are short. Following full imbibition, the different decay rates of the self-correlation function of the core-to-end vector illustrate that arms take a longer time to reach the equilibrium state as the functionality, arm length, and degree of confinement increase, in agreement with recent experimental findings. Furthermore, the star topology induces a stronger effect of adsorption and friction, which becomes more pronounced with increasing functionality.
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Affiliation(s)
- Jianwei Zhang
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jinyu Lei
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Pu Feng
- School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, China
| | - George Floudas
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
- Department of Physics, University of Ioannina, 45110 Ioannina, Greece
- Institute of Materials Science and Computing, University Research Center of Ioannina (URCI), 45110 Ioannina, Greece
| | - Guangzhao Zhang
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jiajia Zhou
- South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou 510640, China
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2
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Wu Z, Müller-Plathe F. Slip-Spring Hybrid Particle-Field Molecular Dynamics for Coarse-Graining Branched Polymer Melts: Polystyrene Melts as an Example. J Chem Theory Comput 2022; 18:3814-3828. [PMID: 35617016 DOI: 10.1021/acs.jctc.2c00107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The topology of chains significantly modifies the dynamical properties of polymer melts. Here, we extend a recently developed efficient simulation method, namely the slip-spring hybrid particle-field (SS-hPF) model, to study the structural and dynamical properties of branched polymer melts over large spatial-temporal scales. In the coarse-grained SS-hPF simulation of polymers, the bonded potentials are derived by iterative Boltzmann inversion from the underlying fine-grained model. The nonbonded potentials are computed from a density functional field instead of pairwise interactions used in standard molecular dynamics simulations, which increases the computational efficiency by a factor of 10-20. The entangled dynamics is lost due to the soft-core nature of density functional field interactions. It is recovered by a multichain slip-spring model that is rigorously parametrized from existing experimental or simulation data. To quantitatively predict the relaxation and diffusion of branched polymers, which are dominated by arm retraction rather than chain reptation, the slip-spring algorithm is augmented to improve the polymer dynamics near the branch point. Multiple dynamical observables, e.g., diffusion coefficients, arm relaxations, and tube survival probabilities, are characterized in an example coarse-grained model of symmetric and asymmetric star-shaped polystyrene melts. Consistent dynamical behaviors are identified and compared with theoretical predictions. With a single rescaling factor, the prediction of diffusion coefficients agrees well with the available experimental measurements. In this work, an efficient approach is provided to build chemistry-specific coarse-grained models for predicting the dynamics of branched polymers.
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Affiliation(s)
- Zhenghao Wu
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
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3
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Masubuchi Y, Doi Y, Uneyama T. Effects of Slip-Spring Parameters and Rouse Bead Density on Polymer Dynamics in Multichain Slip-Spring Simulations. J Phys Chem B 2022; 126:2930-2941. [PMID: 35298156 DOI: 10.1021/acs.jpcb.2c00697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The multichain slip-spring (MCSS) model is one of the coarse-grained models of polymers developed in the niche between bead-spring models and tube type descriptions. In this model, polymers are represented by Rouse chains connected by virtual springs that temporally connect the chains, hop along the chain, and are constructed and annihilated at the chain ends. Earlier studies have shown that MCSS simulations can nicely reproduce entangled and unentangled polymer dynamics. However, the model parameters have been chosen arbitrarily, and their effects have not been reported. In this study, for the first time, we systematically investigated the effects of model parameters: fugacity of virtual springs, its intensity, and the Rouse bead density. We validated the employed simulation code by confirming that the statistics of the system follow the theoretical setup. Namely, the virtual spring density is correctly controlled, and polymer chains exhibit ideal chain statistics irrespective of the chosen parameter values. For diffusion and linear viscoelasticity, simulation results obtained for different parameters can be superposed with each other by conversion factors for the bead number per chain and units of length, time, and modulus. These conversion factors follow scaling laws concerning the number of Rouse segments between two consecutive anchoring points of virtual springs along the polymer chain. Besides, diffusion and viscoelasticity excellently agree with literature data for the standard bead-spring simulation. These results imply that the coarse-graining level for the MCSS model can be arbitrarily chosen and controlled by model parameters.
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Affiliation(s)
- Yuichi Masubuchi
- Department of Materials Physics, Nagoya University, Nagoya 4648603, Japan
| | - Yuya Doi
- Department of Materials Physics, Nagoya University, Nagoya 4648603, Japan
| | - Takashi Uneyama
- Department of Materials Physics, Nagoya University, Nagoya 4648603, Japan
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4
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Zhao L, Li Z, Wang Z, Caswell B, Ouyang J, Karniadakis GE. Active- and transfer-learning applied to microscale-macroscale coupling to simulate viscoelastic flows. JOURNAL OF COMPUTATIONAL PHYSICS 2021; 427:110069. [DOI: 10.1016/j.jcp.2020.110069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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5
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Shanbhag S, Wang Z. Molecular Simulation of Tracer Diffusion and Self-Diffusion in Entangled Polymers. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sachin Shanbhag
- Department of Scientific Computing, Florida State University, Tallahassee, Florida 32306, United States
| | - Zuowei Wang
- Department of Mathematics and Statistics, University of Reading, Reading RG6 6AX, U.K
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6
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Abstract
AbstractThe asymmetric star polymers are studied by coarse grain simulations. Each polymer chain is represented by number of consecutive soft blobs and additional uncrossability constraints are added to prevent chain crossings. In this work two types of asymmetric star polymers with different backbone lengths are structured. Their dynamical properties are discussed by comparisons with corresponding linear chains, the one covers chain length along with the asymmetric arm through the branch point to one of the symmetric arm, or the backbone chain between two symmetric arm ends, or the largest linear possesses the same molecular weight of the entire star. To reveal the influence of the asymmetric arm length on their relaxation decay times, the autocorrelation function of the vectors from each branching point to corresponding asymmetric arm end are calculated, results are compared with the symmetric star having the same backbone chain.
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7
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Xi L. Molecular simulation for predicting the rheological properties of polymer melts. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1605600] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Li Xi
- Department of Chemical Engineering, McMaster University, Hamilton, Ontario, Canada
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8
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Cao J, Wang Z, Likhtman AE. Determining Tube Theory Parameters by Slip-Spring Model Simulations of Entangled Star Polymers in Fixed Networks. Polymers (Basel) 2019; 11:E496. [PMID: 30960480 PMCID: PMC6473678 DOI: 10.3390/polym11030496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 11/26/2022] Open
Abstract
Dynamical properties of branched polymer melts are determined by the polymer molecular weights and architectures containing junction points. Relaxation of entangled symmetric star polymers proceeds via arm-retraction and constraint release (CR). In this work, we investigate arm-retraction dynamics in the framework of a single-chain slip-spring model without CR effect where entanglements are treated as binary contacts, conveniently modeled as virtual "slip-links", each involving two neighboring strands. The model systems are analogous to isolated star polymers confined in a permanent network or a melt of very long linear polymers. We find that the distributions of the effective primitive path lengths are Gaussian, from which the entanglement molecular weight N e , a key tube theory parameter, can be extracted. The procured N e value is in good agreement with that obtained from mapping the middle monomer mean-square displacements of entangled linear chains in slip-spring model to the tube model prediction. Furthermore, the mean first-passage (FP) times of destruction of original tube segments by the retracting arm end are collected in simulations and examined quantitatively using a theory recently developed in our group for describing FP problems of one-dimensional Rouse chains with improbable extensions. The asymptotic values of N e as obtained from the static (primitive path length) and dynamical (FP time) analysis are consistent with each other. Additionally, we manage to determine the tube survival function of star arms μ ( t ) , or equivalently arm end-to-end vector relaxation function ϕ ( t ) , through the mean FP time spectrum τ ( s ) of the tube segments after careful consideration of the inner-most entanglements, which shows reasonably good agreement with experimental data on dielectric relaxation.
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Affiliation(s)
- Jing Cao
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, UK.
| | - Zuowei Wang
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, UK.
| | - Alexei E Likhtman
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, UK
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9
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Affiliation(s)
- Yuichi Masubuchi
- Department of Materials Physics, Nagoya University, Nagoya, Japan
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10
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Wijesinghe S, Perahia D, Grest GS. Polymer Topology Effects on Dynamics of Comb Polymer Melts. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01449] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Sidath Wijesinghe
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Dvora Perahia
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Gary S. Grest
- Sandia
National
Laboratories, Albuquerque, New Mexico 87185, United States
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11
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Masubuchi Y, Uneyama T. Comparison among multi-chain models for entangled polymer dynamics. SOFT MATTER 2018; 14:5986-5994. [PMID: 29926890 DOI: 10.1039/c8sm00948a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Although lots of coarse-grained models have been proposed to trace the long-term behaviors of entangled polymers, compatibility among the different models has not been frequently discussed. In this study, some dynamical and static quantities, such as diffusion, relaxation modulus, chain dimension, and entanglement density, were examined for the multi-chain slip-link model (primitive chain network model) and the multi-chain slip-spring model, and the results were compared with those reported for the standard bead-spring model. For the diffusion, three models are compatible with scale-conversion parameters for units of length, time and bead (segment) number (or the molecular weight). The relaxation modulus is also compatible given that the model dependence can be accommodated by the entanglement density and the additional scale-conversion for the unit of modulus. The chain dimension is reasonably coincident with small deviations due to the weak non-Gaussianity of the models. Apart from these plausible compatibilities, significant discrepancies have been found for the inter-chain cross-correlations in the relaxation modulus.
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12
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Holler S, Moreno AJ, Zamponi M, Bačová P, Willner L, Iatrou H, Falus P, Richter D. The Role of the Functionality in the Branch Point Motion in Symmetric Star Polymers: A Combined Study by Simulations and Neutron Spin Echo Spectroscopy. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01579] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Stefan Holler
- Forschungszentrum
Jülich GmbH, 52425 Jülich, Germany
- Centro de Física
de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - Angel J. Moreno
- Centro de Física
de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Donostia
International
Physics Center, Paseo Manuel de Lardizabal
4, 20018 San Sebastian, Spain
| | | | - Petra Bačová
- Centro de Física
de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Institute
of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), 71110 Heraklion, Crete Greece
| | - Lutz Willner
- Forschungszentrum
Jülich GmbH, 52425 Jülich, Germany
| | - Hermis Iatrou
- Department
of Chemistry, University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece
| | - Peter Falus
- Institut Laue-Langevin, 71 Avenue
des Martyrs, CS 20156, Cedex 9 38042 Grenoble, France
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13
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Li Z, Bian X, Yang X, Karniadakis GE. A comparative study of coarse-graining methods for polymeric fluids: Mori-Zwanzig vs. iterative Boltzmann inversion vs. stochastic parametric optimization. J Chem Phys 2017; 145:044102. [PMID: 27475343 DOI: 10.1063/1.4959121] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We construct effective coarse-grained (CG) models for polymeric fluids by employing two coarse-graining strategies. The first one is a forward-coarse-graining procedure by the Mori-Zwanzig (MZ) projection while the other one applies a reverse-coarse-graining procedure, such as the iterative Boltzmann inversion (IBI) and the stochastic parametric optimization (SPO). More specifically, we perform molecular dynamics (MD) simulations of star polymer melts to provide the atomistic fields to be coarse-grained. Each molecule of a star polymer with internal degrees of freedom is coarsened into a single CG particle and the effective interactions between CG particles can be either evaluated directly from microscopic dynamics based on the MZ formalism, or obtained by the reverse methods, i.e., IBI and SPO. The forward procedure has no free parameters to tune and recovers the MD system faithfully. For the reverse procedure, we find that the parameters in CG models cannot be selected arbitrarily. If the free parameters are properly defined, the reverse CG procedure also yields an accurate effective potential. Moreover, we explain how an aggressive coarse-graining procedure introduces the many-body effect, which makes the pairwise potential invalid for the same system at densities away from the training point. From this work, general guidelines for coarse-graining of polymeric fluids can be drawn.
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Affiliation(s)
- Zhen Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Xin Bian
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Xiu Yang
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
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14
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Li Z, Lee HS, Darve E, Karniadakis GE. Computing the non-Markovian coarse-grained interactions derived from the Mori–Zwanzig formalism in molecular systems: Application to polymer melts. J Chem Phys 2017; 146:014104. [DOI: 10.1063/1.4973347] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Zhen Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Hee Sun Lee
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA
| | - Eric Darve
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
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15
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Regan K, Ricketts S, Robertson-Anderson RM. DNA as a Model for Probing Polymer Entanglements: Circular Polymers and Non-Classical Dynamics. Polymers (Basel) 2016; 8:E336. [PMID: 30974610 PMCID: PMC6432451 DOI: 10.3390/polym8090336] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/25/2016] [Accepted: 08/25/2016] [Indexed: 02/04/2023] Open
Abstract
Double-stranded DNA offers a robust platform for investigating fundamental questions regarding the dynamics of entangled polymer solutions. The exceptional monodispersity and multiple naturally occurring topologies of DNA, as well as a wide range of tunable lengths and concentrations that encompass the entanglement regime, enable direct testing of molecular-level entanglement theories and corresponding scaling laws. DNA is also amenable to a wide range of techniques from passive to nonlinear measurements and from single-molecule to bulk macroscopic experiments. Over the past two decades, researchers have developed methods to directly visualize and manipulate single entangled DNA molecules in steady-state and stressed conditions using fluorescence microscopy, particle tracking and optical tweezers. Developments in microfluidics, microrheology and bulk rheology have also enabled characterization of the viscoelastic response of entangled DNA from molecular levels to macroscopic scales and over timescales that span from linear to nonlinear regimes. Experiments using DNA have uniquely elucidated the debated entanglement properties of circular polymers and blends of linear and circular polymers. Experiments have also revealed important lengthscale and timescale dependent entanglement dynamics not predicted by classical tube models, both validating and refuting new proposed extensions and alternatives to tube theory and motivating further theoretical work to describe the rich dynamics exhibited in entangled polymer systems.
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Affiliation(s)
- Kathryn Regan
- Department of Physics and Biophysics, University of San Diego, San Diego, CA 92110, USA.
| | - Shea Ricketts
- Department of Physics and Biophysics, University of San Diego, San Diego, CA 92110, USA.
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16
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Cao J, Wang Z. Microscopic Picture of Constraint Release Effects in Entangled Star Polymer Melts. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00554] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Jing Cao
- Department of Mathematics
and Statistics, University of Reading, Whiteknights, PO Box 220, Reading RG6 6AX, U.K
| | - Zuowei Wang
- Department of Mathematics
and Statistics, University of Reading, Whiteknights, PO Box 220, Reading RG6 6AX, U.K
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17
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Kim JM, Baig C. Communication: Role of short chain branching in polymer structure and dynamics. J Chem Phys 2016; 144:081101. [PMID: 26931673 DOI: 10.1063/1.4942351] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A comprehensive understanding of chain-branching effects, essential for establishing general knowledge of the structure-property-phenomenon relationship in polymer science, has not yet been found, due to a critical lack of knowledge on the role of short-chain branches, the effects of which have mostly been neglected in favor of the standard entropic-based concepts of long polymers. Here, we show a significant effect of short-chain branching on the structural and dynamical properties of polymeric materials, and reveal the molecular origins behind the fundamental role of short branches, via atomistic nonequilibrium molecular dynamics and mesoscopic Brownian dynamics by systematically varying the strength of the mobility of short branches. We demonstrate that the fast random Brownian kinetics inherent to short branches plays a key role in governing the overall structure and dynamics of polymers, leading to a compact molecular structure and, under external fields, to a lesser degree of structural deformation of polymer, to a reduced shear-thinning behavior, and to a smaller elastic stress, compared with their linear analogues. Their fast dynamical nature being unaffected by practical flow fields owing to their very short characteristic time scale, short branches would substantially influence (i.e., facilitate) the overall relaxation behavior of polymeric materials under various flowing conditions.
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Affiliation(s)
- Jun Mo Kim
- Department of Chemical Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
| | - Chunggi Baig
- Department of Chemical Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
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18
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Li Z, Bian X, Li X, Karniadakis GE. Incorporation of memory effects in coarse-grained modeling via the Mori-Zwanzig formalism. J Chem Phys 2015; 143:243128. [PMID: 26723613 PMCID: PMC4644152 DOI: 10.1063/1.4935490] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/29/2015] [Indexed: 11/14/2022] Open
Abstract
The Mori-Zwanzig formalism for coarse-graining a complex dynamical system typically introduces memory effects. The Markovian assumption of delta-correlated fluctuating forces is often employed to simplify the formulation of coarse-grained (CG) models and numerical implementations. However, when the time scales of a system are not clearly separated, the memory effects become strong and the Markovian assumption becomes inaccurate. To this end, we incorporate memory effects into CG modeling by preserving non-Markovian interactions between CG variables, and the memory kernel is evaluated directly from microscopic dynamics. For a specific example, molecular dynamics (MD) simulations of star polymer melts are performed while the corresponding CG system is defined by grouping many bonded atoms into single clusters. Then, the effective interactions between CG clusters as well as the memory kernel are obtained from the MD simulations. The constructed CG force field with a memory kernel leads to a non-Markovian dissipative particle dynamics (NM-DPD). Quantitative comparisons between the CG models with Markovian and non-Markovian approximations indicate that including the memory effects using NM-DPD yields similar results as the Markovian-based DPD if the system has clear time scale separation. However, for systems with small separation of time scales, NM-DPD can reproduce correct short-time properties that are related to how the system responds to high-frequency disturbances, which cannot be captured by the Markovian-based DPD model.
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Affiliation(s)
- Zhen Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Xin Bian
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Xiantao Li
- Department of Mathematics, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
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19
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Snijkers F, Pasquino R, Olmsted PD, Vlassopoulos D. Perspectives on the viscoelasticity and flow behavior of entangled linear and branched polymers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:473002. [PMID: 26558404 DOI: 10.1088/0953-8984/27/47/473002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We briefly review the recent advances in the rheology of entangled polymers and identify emerging research trends and outstanding challenges, especially with respect to branched polymers. Emphasis is placed on the role of well-characterized model systems, as well as the synergy of synthesis-characterization, rheometry and modeling/simulations. The theoretical framework for understanding the observed linear and nonlinear rheological phenomena is the tube model, which is critically assessed in view of its successes and shortcomings, and alternative approaches are briefly discussed. Finally, intriguing experimental findings and controversial issues that merit consistent explanation, such as shear banding instabilities, multiple stress overshoots in transient simple shear and enhanced steady-state elongational viscosity in polymer solutions, are discussed, and future directions such as branch point dynamics and anisotropic monomeric friction are outlined.
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Affiliation(s)
- F Snijkers
- FORTH, Institute of Electronic Structure and Laser, Heraklion, Crete 71110, Greece. CNRS/Solvay UMR 5268, Laboratoire Polymères et Matériaux Avancés, Saint-Fons 69190, France
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20
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Luo Z, Pei J. Core Cross-Linked Star Polymer Prepared Via Arm-Linking Reaction Mediated By 1,1-Diphenylethene Radical Polymerization System. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2015. [DOI: 10.1080/10601325.2015.1063867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Cao J, Cheng F, Cao H, Lu A, Cai M, Chen Y, He B, Gu Z, Luo X. Framework effect of amphiphilic polyesters on their molecular movement and protein adsorption-resistance properties. Colloids Surf B Biointerfaces 2015; 125:213-21. [DOI: 10.1016/j.colsurfb.2014.11.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 11/05/2014] [Accepted: 11/25/2014] [Indexed: 12/17/2022]
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22
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Li Z, Bian X, Caswell B, Karniadakis GE. Construction of dissipative particle dynamics models for complex fluids via the Mori-Zwanzig formulation. SOFT MATTER 2014; 10:8659-8672. [PMID: 25252001 DOI: 10.1039/c4sm01387e] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a bottom-up coarse-graining procedure to construct mesoscopic force fields directly from microscopic dynamics. By grouping many bonded atoms in the molecular dynamics (MD) system into a single cluster, we compute both the conservative and non-conservative interactions between neighboring clusters. In particular, we perform MD simulations of polymer melts to provide microscopic trajectories for evaluating coarse-grained (CG) interactions. Subsequently, dissipative particle dynamics (DPD) is considered as the effective dynamics resulting from the Mori-Zwanzig (MZ) projection of the underlying atomistic dynamics. The forces between finite-size clusters have, in general, both radial and transverse components and hence we employ four different DPD models to account differently for such interactions. Quantitative comparisons between these DPD models indicate that the DPD models with MZ-guided force fields yield much better static and dynamics properties, which are consistent with the underlying MD system, compared to standard DPD with empirical formulae. When the rotational motion of the particle is properly taken into account, the entire velocity autocorrelation function of the MD system as well as the pair correlation function can be accurately reproduced by the MD-informed DPD model. Since this coarse-graining procedure is performed on an unconstrained MD system, our framework is general and can be used in other soft matter systems in which the clusters can be faithfully defined as CG particles.
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Affiliation(s)
- Zhen Li
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA.
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23
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Bačová P, Moreno AJ. Real-Space Analysis of Branch Point Motion in Architecturally Complex Polymers. Macromolecules 2014. [DOI: 10.1021/ma501405n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Petra Bačová
- Departamento
de Física de Materiales, Universidad del País Vasco (UPV/EHU), Apartado 1072, 20080 San Sebastián, Spain
- Materials Physics
Center MPC, Paseo Manuel de Lardizabal
5, 20018 San Sebastián, Spain
| | - Angel J. Moreno
- Materials Physics
Center MPC, Paseo Manuel de Lardizabal
5, 20018 San Sebastián, Spain
- Centro de Física
de Materiales (CSIC, UPV/EHU), Paseo
Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International
Physics Center, Paseo Manuel de Lardizabal
4, 20018 San Sebastián, Spain
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24
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Bačová P, Lentzakis H, Read DJ, Moreno AJ, Vlassopoulos D, Das C. Branch-Point Motion in Architecturally Complex Polymers: Estimation of Hopping Parameters from Computer Simulations and Experiments. Macromolecules 2014. [DOI: 10.1021/ma5003936] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Petra Bačová
- Centro de Física
de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
| | - Helen Lentzakis
- Institute of Electronic Structure & Laser, Foundation for Research and Technology Hellas (FORTH), Heraklion, Crete 71110, Greece
- Department
of Materials Science and Technology, Univerisity of Crete, Heraklion, Crete 71300, Greece
| | - Daniel J. Read
- Department
of Applied Mathematics, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Angel J. Moreno
- Centro de Física
de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
- Donostia International
Physics Center, Paseo Manuel de Lardizabal 4, E-20018 San Sebastián, Spain
| | - Dimitris Vlassopoulos
- Institute of Electronic Structure & Laser, Foundation for Research and Technology Hellas (FORTH), Heraklion, Crete 71110, Greece
- Department
of Materials Science and Technology, Univerisity of Crete, Heraklion, Crete 71300, Greece
| | - Chinmay Das
- School of
Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
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25
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Bačová P, Hawke LGD, Read DJ, Moreno AJ. Dynamics of Branched Polymers: A Combined Study by Molecular Dynamics Simulations and Tube Theory. Macromolecules 2013. [DOI: 10.1021/ma4005988] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Petra Bačová
- Departamento de Física de Materiales, Universidad del País Vasco (UPV/EHU), Apartado
1072, 20080 San Sebastián, Spain
| | | | - Daniel J. Read
- Department of Applied Mathematics, University of Leeds, LS2 9JT Leeds, U.K
| | - Angel J. Moreno
- Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo
Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018
San Sebastián, Spain
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26
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Ianniruberto G, Marrucci G. Entangled Melts of Branched PS Behave Like Linear PS in the Steady State of Fast Elongational Flows. Macromolecules 2012. [DOI: 10.1021/ma302131b] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giovanni Ianniruberto
- Department of Chemical Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Napoli,
Italy
| | - Giuseppe Marrucci
- Department of Chemical Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Napoli,
Italy
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27
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Abstract
The extreme sensitivity of rheology to the microstructure of polymer melts has prompted the development of “analytical rheology,” which seeks inferring the structure and composition of an unknown sample based on rheological measurements. Typically, this involves the inversion of a model, which may be mathematical, computational, or completely empirical. Despite the imperfect state of existing models, analytical rheology remains a practically useful enterprise. I review its successes and failures in inferring the molecular weight distribution of linear polymers and the branching content in branched polymers.
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Affiliation(s)
- Sachin Shanbhag
- Department of Scientific Computing, Florida State University, Tallahassee, FL 32306, USA
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28
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Hutchings LR. Complex Branched Polymers for Structure–Property Correlation Studies: The Case for Temperature Gradient Interaction Chromatography Analysis. Macromolecules 2012. [DOI: 10.1021/ma3005422] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Lian R. Hutchings
- Durham Centre for
Soft Matter, Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
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29
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Wang Z, Likhtman AE, Larson RG. Segmental Dynamics in Entangled Linear Polymer Melts. Macromolecules 2012. [DOI: 10.1021/ma202759v] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zuowei Wang
- School of Mathematical
and Physical
Sciences, University of Reading, Whiteknights,
Reading RG6 6AX, United Kingdom
| | - Alexei E. Likhtman
- School of Mathematical
and Physical
Sciences, University of Reading, Whiteknights,
Reading RG6 6AX, United Kingdom
| | - Ronald G. Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136,
United States
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30
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Hutchings LR, Kimani SM, Hoyle DM, Read DJ, Das C, McLeish TCB, Chang T, Lee H, Auhl D. In Silico Molecular Design, Synthesis, Characterization, and Rheology of Dendritically Branched Polymers: Closing the Design Loop. ACS Macro Lett 2012; 1:404-408. [PMID: 35578511 DOI: 10.1021/mz300059k] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It has been a long held ambition of both industry and academia to understand the relationship between the often complex molecular architecture of polymer chains and their melt flow properties, with the goal of building robust theoretical models to predict their rheology. The established key to this is the use of well-defined, model polymers, homogeneous in chain length and architecture. We describe here for the first time, the in silico design, synthesis, and characterization of an architecturally complex, branched polymer with the optimal rheological properties for such structure-property correlation studies. Moreover, we demonstrate unequivocally the need for accurate characterization using temperature gradient interaction chromatography (TGIC), which reveals the presence of heterogeneities in the molecular structure that are undetectable by size exclusion chromatography (SEC). Experimental rheology exposes the rich pattern of relaxation dynamics associated with branched polymers, but the ultimate test is, of course, did the theoretical (design) model accurately predict the rheological properties of the synthesized model branched polymer? Rarely, if ever before, has such a combination of theory, synthesis, characterization, and analysis resulted in a "yes", expressed without doubt or qualification.
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Affiliation(s)
- Lian R. Hutchings
- Durham Centre for Soft Matter, Department of Chemistry, Durham University, Durham, DH1 3LE, United Kingdom
| | - Solomon M. Kimani
- Durham Centre for Soft Matter, Department of Chemistry, Durham University, Durham, DH1 3LE, United Kingdom
| | - David M. Hoyle
- Durham Centre for Soft Matter, Department of Chemistry, Durham University, Durham, DH1 3LE, United Kingdom
| | - Daniel J. Read
- School of Mathematics, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Chinmay Das
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Thomas C. B. McLeish
- Durham Centre for Soft Matter, Department of Chemistry, Durham University, Durham, DH1 3LE, United Kingdom
| | - Taihyun Chang
- Department of Chemistry
and Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang 790784, Republic of Korea
| | - Hyojoon Lee
- Department of Chemistry
and Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang 790784, Republic of Korea
| | - Dietmar Auhl
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
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31
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Snijkers F, van Ruymbeke E, Kim P, Lee H, Nikopoulou A, Chang T, Hadjichristidis N, Pathak J, Vlassopoulos D. Architectural Dispersity in Model Branched Polymers: Analysis and Rheological Consequences. Macromolecules 2011. [DOI: 10.1021/ma2013805] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Frank Snijkers
- FORTH, Institute of Electronic Structure & Laser, Heraklion, Crete, Greece
| | - Evelyne van Ruymbeke
- FORTH, Institute of Electronic Structure & Laser, Heraklion, Crete, Greece
- Bio and Soft Matter, Institute on Condensed Matter and Nano-science, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Paul Kim
- Department of Chemistry and Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - Hyojoon Lee
- Department of Chemistry and Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | | | - Taihyun Chang
- Department of Chemistry and Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | | | - Jai Pathak
- FORTH, Institute of Electronic Structure & Laser, Heraklion, Crete, Greece
| | - Dimitris Vlassopoulos
- FORTH, Institute of Electronic Structure & Laser, Heraklion, Crete, Greece
- Department of Materials Science & Technology, University of Crete, Heraklion, Crete, Greece
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32
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Masubuchi Y, Yaoita T, Matsumiya Y, Watanabe H. Primitive chain network simulations for asymmetric star polymers. J Chem Phys 2011; 134:194905. [PMID: 21599086 DOI: 10.1063/1.3590276] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yuichi Masubuchi
- Institute for Chemical Research, Kyoto University, Gokasyo, Uji, Kyoto 611-0011, Japan.
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33
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Ahmadi M, Bailly C, Keunings R, Nekoomanesh M, Arabi H, van Ruymbeke E. Time Marching Algorithm for Predicting the Linear Rheology of Monodisperse Comb Polymer Melts. Macromolecules 2011. [DOI: 10.1021/ma102041h] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mostafa Ahmadi
- Bio and Soft Matter, Institute of Condensed Matter and Nano-science, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- Polymerization Group, Engineering Department, Iran Polymer and Petrochemical Institute, Tehran, Iran
| | - Christian Bailly
- Bio and Soft Matter, Institute of Condensed Matter and Nano-science, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Roland Keunings
- Louvain School of Engineering, ICTEAM Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Mehdi Nekoomanesh
- Polymerization Group, Engineering Department, Iran Polymer and Petrochemical Institute, Tehran, Iran
| | - Hassan Arabi
- Polymerization Group, Engineering Department, Iran Polymer and Petrochemical Institute, Tehran, Iran
| | - Evelyne van Ruymbeke
- Bio and Soft Matter, Institute of Condensed Matter and Nano-science, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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34
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Wu L, Wang L, Wang X, Xu K. Synthesis, characterizations and biocompatibility of novel biodegradable star block copolymers based on poly[(R)-3-hydroxybutyrate] and poly(epsilon-caprolactone). Acta Biomater 2010; 6:1079-89. [PMID: 19671452 DOI: 10.1016/j.actbio.2009.08.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 06/24/2009] [Accepted: 08/07/2009] [Indexed: 10/20/2022]
Abstract
Star block copolymers based on poly[(R)-3-hydroxybutyrate] (PHB) and poly(epsilon-caprolactone) (PCL), termed SPHBCL, were successfully synthesized with structural variation on arm numbers and lengths via coupling reactions and ring opening polymerizations. Arm numbers 3, 4 and 6 of SPHBCL were synthesized by using different multifunctional cores, such as trimethyol propane, pentaerythiritol and dipentaerthritol, respectively. Gel permeation chromatography (GPC) and (1)H and (13)C nuclear magnetic resonance were used to characterize the structure of SPHBCL. GPC failed to produce accurate molecular weights of the SPHBCL due to the discrepancy of star copolymer structures. The melting temperature of SPHBCL decreased with increasing degree of branching. Thermal decomposition temperature was revealed to be lower than that of linear block copolymer LPHBCL counterparts based on PHB and PCL. Films made from various SPHBCL copolymers had different porous or networking surface morphology, and all possessed improved biocompatibility in terms of less blood clotting and more osteoblast cell growth compared with their corresponding homopolymers PHB and PCL. Among them, it was found, however, that the 4-arm star block copolymer 4SPHBCL-25 showed unique surface properties, i.e. a regular nanoravine structure was observed by scanning electron microscopy and atomic force microscopy. This 4-arm star copolymer also showed the best biocompatibility.
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35
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Baig C, Alexiadis O, Mavrantzas VG. Advanced Monte Carlo Algorithm for the Atomistic Simulation of Short- and Long-Chain Branched Polymers: Implementation for Model H-Shaped, A3AA3 Multiarm (Pom-Pom), and Short-Chain Branched Polyethylene Melts. Macromolecules 2009. [DOI: 10.1021/ma902199g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Chunggi Baig
- Department of Chemical Engineering, University of Patras & FORTH-ICE/HT, Patras, GR 26504, Greece
| | - Orestis Alexiadis
- Department of Chemical Engineering, University of Patras & FORTH-ICE/HT, Patras, GR 26504, Greece
| | - Vlasis G. Mavrantzas
- Department of Chemical Engineering, University of Patras & FORTH-ICE/HT, Patras, GR 26504, Greece
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36
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Kirkwood KM, Leal LG, Vlassopoulos D, Driva P, Hadjichristidis N. Stress Relaxation of Comb Polymers with Short Branches. Macromolecules 2009. [DOI: 10.1021/ma900950s] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Dimitris Vlassopoulos
- Institute of Electronic Structure & Laser, FORTH, Heraklion 71110, Crete, Greece
- Department of Materials Science & Technology, University of Crete, Heraklion 71003, Crete, Greece
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37
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Zamponi M, Pyckhout-Hintzen W, Wischnewski A, Monkenbusch M, Willner L, Kali G, Richter D. Molecular Observation of Branch Point Motion in Star Polymer Melts. Macromolecules 2009. [DOI: 10.1021/ma9017185] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | | | | | - György Kali
- Institut Laue-Langevin, 6 rue Jules Horowitz, 38000 Grenoble, France
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38
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Pryamitsyn V, Ganesan V. Screening of hydrodynamic interactions in Brownian rod suspensions. J Chem Phys 2008; 128:134901. [PMID: 18397101 DOI: 10.1063/1.2842075] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the details and results of a simulation study addressing the dynamics and rheology of rod suspensions over a wide regime of concentrations ranging from dilute to concentrated systems. Our study compares the results of two complementary simulation methods. The first method adapts a recently proposed explicit solvent simulation strategy and incorporates both hydrodynamical effects and steric interactions between the rod units. We compare the results of such a method with those obtained from a Brownian dynamics simulation approach which retains the steric interactions but neglects the effects of hydrodynamic interactions. Overall, our results in the context of the translational and rotational diffusivities are in agreement with the hydrodynamical predictions in the dilute regime and the corresponding results of the tube model and its extensions thereof in the semidilute regimes. The latter results suggest that effects of hydrodynamic interactions on the translational and rotational diffusivities are secondary relative to the steric interactions and at best lead only to a small correction to the results of the classical tube model. Our results in the context of linear viscoelasticity also broadly confirms the predictions of the tube model for the storage and loss moduli and allows us to extract for the first time the independent hydrodynamic and Brownian contributions to the zero shear viscosity. While the relative magnitudes of these contributions are consistent with the theoretical predictions, the quantitative magnitudes are quite different from the theoretical predictions. Overall, these results confirm the validity of the hydrodynamic "screening" hypothesis and ratify the neglect of hydrodynamical stresses in quantifying the linear rheology of Brownian rod suspensions.
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Affiliation(s)
- Victor Pryamitsyn
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA
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39
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Wang Z, Larson RG. Constraint Release in Entangled Binary Blends of Linear Polymers: A Molecular Dynamics Study. Macromolecules 2008. [DOI: 10.1021/ma800680b] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zuowei Wang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136
| | - Ronald G. Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136
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40
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Larson RG. Looking inside the entanglement “tube” using molecular dynamics simulations. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/polb.21332] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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