1
|
Kruteva M, Allgaier J, Monkenbusch M, Valiullin R, Hoffmann I, Richter D. Cooperative Dynamics of Highly Entangled Linear Polymers within the Entanglement Tube. ACS Macro Lett 2024; 13:335-340. [PMID: 38427591 PMCID: PMC10956489 DOI: 10.1021/acsmacrolett.3c00738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/16/2024] [Accepted: 02/27/2024] [Indexed: 03/03/2024]
Abstract
We present a quantitative comparison of the dynamic structure factors from unentangled and strongly entangled poly(butylene oxide) (PBO) melts. As expected, the low molecular weight PBO displays Rouse dynamics, however, with very significant subdiffusive center-of-mass diffusion. The spectra from high molecular weight entangled PBO can be very well described by the dynamic structure factor based on the concept of local reptation, including the Rouse dynamics within the tube and allowing for non-Gaussian corrections. Comparing quantitatively the spectra from both polymers leads to the surprising result that their spectra differ only by the contribution of classical Rouse diffusion for the low molecular weight melt. The subdiffusive component is common for both the low and high molecular weight PBO melts, indicating that in both melts the same interchain potential is active, thereby supporting the validity of the Generalized Langevin Equation approach.
Collapse
Affiliation(s)
- Margarita Kruteva
- Jülich
Centre for Neutron Science (JCNS-1) and Institute for Biological Information
Processing (IBI-8), Forschungszentrum Jülich
GmbH, 52428 Jülich, Germany
| | - Jürgen Allgaier
- Jülich
Centre for Neutron Science (JCNS-1) and Institute for Biological Information
Processing (IBI-8), Forschungszentrum Jülich
GmbH, 52428 Jülich, Germany
| | - Michael Monkenbusch
- Jülich
Centre for Neutron Science (JCNS-1) and Institute for Biological Information
Processing (IBI-8), Forschungszentrum Jülich
GmbH, 52428 Jülich, Germany
| | - Rustem Valiullin
- Felix
Bloch Institute for Solid State Physics, Leipzig University, 04103 Leipzig, Germany
| | - Ingo Hoffmann
- Institut
Laue-Langevin (ILL), 71 avenue des Martyrs, 38000 Grenoble, France
| | - Dieter Richter
- Jülich
Centre for Neutron Science (JCNS-2) and Peter Grünberg Institute
(PGI-4), Forschungszentrum Jülich
GmbH, 52428 Jülich, Germany
| |
Collapse
|
2
|
Li Y, Yao P, Guo H. Non-Rouse behavior of short ring polymers in melts by molecular dynamics simulations. SOFT MATTER 2023; 19:7161-7171. [PMID: 37702037 DOI: 10.1039/d3sm00668a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Short ring polymers are expected to behave nearly Rouse-like due to the little effect of topological constraints of non-knot and non-concatenation. However, this notion is questioned because of several simulation and experiment findings in recent times, which requires a further more quantitative study. Therefore, we perform a deep investigation of statics and dynamics of flexible short ring polymers (N < 2Ne) in melts via molecular dynamics simulations by further taking linear analogues as well as all-crossing ring and linear polymers with switched off topological constraints for comparisons and demonstrate the noticeable deviations from the Rouse model in terms of local and global scales. Although the overall size is compact, the subchains are swollen, which is traced back to the deeper "segmental correlation hole" effect. The same scaling relationship of the non-Gaussian deviation of the static structure factor holds, but the deviation magnitude of rings is larger than that of linear analogues. By checking the non-Gaussian parameter and autocorrelation function of center-of-mass velocity, the physical origin of anomalous sub-diffusions of short rings is identified as unscreened viscoelastic hydrodynamic interactions and not correlation hole effects, like linear analogues.
Collapse
Affiliation(s)
- Yedi Li
- Beijing National Laboratory for Molecular Sciences, Joint Laboratory of Polymer Sciences and Materials, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pu Yao
- Beijing National Laboratory for Molecular Sciences, Joint Laboratory of Polymer Sciences and Materials, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongxia Guo
- Beijing National Laboratory for Molecular Sciences, Joint Laboratory of Polymer Sciences and Materials, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
3
|
Ghanta R, Burkhart C, Polińska P, Harmandaris V, Doxastakis M. The effect of chemical constitution on polyisoprene dynamics. J Chem Phys 2023; 159:044902. [PMID: 37486059 DOI: 10.1063/5.0155612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/05/2023] [Indexed: 07/25/2023] Open
Abstract
Polyisoprene (PI) melts have been studied, with most reports focusing on systems with high 1,4-cis content. In contrast, 1,4-trans PI homopolymers or random copolymers have seldom been examined, despite a handful of investigations suggesting a distinct dynamic behavior. Herein, we employ all-atom simulations to investigate the effect of chemical architecture on the dynamics of cis and trans-PI homopolymers, as well as copolymers. We examine the thermodynamic, conformational, and structural properties of the polymers and validate the performance of the models. We probe chain dynamics, revealing that cis-PI presents accelerated translation and reorientation modes relative to trans as recorded by the mean square displacement of the chain center-of-mass as well as by the characteristic times of the lower modes in a Rouse analysis. Interestingly, progressing to higher modes, we observe a reversal with trans units exhibiting faster dynamics. This was further confirmed by calculations of local carbon-hydrogen vector reorientation dynamics, which offer a microscopic view of segmental mobility. To obtain insight into the simulation trajectories, we evaluate the intermediate incoherent scattering function that supports a temperature-dependent crossover in relative mobility that extends over separations beyond the Kuhn-length level. Finally, we analyzed the role of non-Gaussian displacements, which demonstrate that cis-PI exhibits increased heterogeneity in dynamics over short-timescales in contrast to trans-PI, where deviations persist over times extending to terminal dynamics. Our all-atom simulations provide a fundamental understanding of PI dynamics and the impact of microstructure while providing important data for the design and optimization of PI-based materials.
Collapse
Affiliation(s)
- Rohit Ghanta
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Tennessee, Knoxville 37996, USA
| | - Craig Burkhart
- The Goodyear Tire & Rubber Company, Akron, Ohio 44305, USA
| | - Patrycja Polińska
- Goodyear Innovation Center Luxembourg, Avenue Gordon Smith, L-7750 Colmar-Berg, Luxembourg
| | - Vagelis Harmandaris
- Department of Applied Mathematics, University of Crete, and IACM FORTH, GR-71110 Heraklion, Greece
- Computation-based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Manolis Doxastakis
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Tennessee, Knoxville 37996, USA
| |
Collapse
|
4
|
Guenza MG. Dynamics of protein droplets revealed by bridging multiple scales. Nature 2023:10.1038/d41586-023-02215-2. [PMID: 37468813 DOI: 10.1038/d41586-023-02215-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
|
5
|
Phillies GDJ. Simulational Tests of the Rouse Model. Polymers (Basel) 2023; 15:2615. [PMID: 37376261 DOI: 10.3390/polym15122615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/24/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
An extensive review of literature simulations of quiescent polymer melts is given, considering results that test aspects of the Rouse model in the melt. We focus on Rouse model predictions for the mean-square amplitudes ⟨(Xp(0))2⟩ and time correlation functions ⟨Xp(0)Xp(t)⟩ of the Rouse mode Xp(t). The simulations conclusively demonstrate that the Rouse model is invalid in polymer melts. In particular, and contrary to the Rouse model, (i) mean-square Rouse mode amplitudes ⟨(Xp(0))2⟩ do not scale as sin-2(pπ/2N), N being the number of beads in the polymer. For small p (say, p≤3) ⟨(Xp(0))2⟩ scales with p as p-2; for larger p, it scales as p-3. (ii) Rouse mode time correlation functions ⟨Xp(t)Xp(0)⟩ do not decay with time as exponentials; they instead decay as stretched exponentials exp(-αtβ). β depends on p, typically with a minimum near N/2 or N/4. (iii) Polymer bead displacements are not described by independent Gaussian random processes. (iv) For p≠q, ⟨Xp(t)Xq(0)⟩ is sometimes non-zero. (v) The response of a polymer coil to a shear flow is a rotation, not the affine deformation predicted by Rouse. We also briefly consider the Kirkwood-Riseman polymer model.
Collapse
|
6
|
Sharma A, Kruteva M, Allgaier J, Hoffmann I, Falus P, Monkenbusch M, Richter D. Chain Confinement and Anomalous Diffusion in the Cross over Regime between Rouse and Reptation. ACS Macro Lett 2022; 11:1343-1348. [PMID: 36409674 DOI: 10.1021/acsmacrolett.2c00608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
By neutron spin echo (NSE) and pulsed field gradient (PFG) NMR, we study the dynamics of a polyethylene-oxide melt (PEO) with a molecular weight in the transition regime between Rouse and reptation dynamics. We analyze the data with a Rouse mode analysis allowing for reduced long wavelength Rouse modes amplitudes. For short times, subdiffusive center-of-mass mean square displacement ⟨rcom2(t)⟩ was allowed. This approach captures the NSE data well and provides accurate information on the topological constraints in a chain length regime, where the tube model is inapplicable. As predicted by reptation for the polymer ⟨rcom2(t)⟩, we experimentally found the subdiffusive regime with an exponent close to μ=12, which, however, crosses over to Fickian diffusion not at the Rouse time, but at a later time, when the ⟨rcom2(t)⟩ has covered a distance related to the tube diameter.
Collapse
Affiliation(s)
- Aakash Sharma
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425Jülich, Germany
| | - Margarita Kruteva
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425Jülich, Germany
| | - Jürgen Allgaier
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425Jülich, Germany
| | - Ingo Hoffmann
- Institut Max von Laue-Paul Langevin (ILL), 71 avenue des Martyrs, CS 20156, Cedex 9, F-38042Grenoble, France
| | - Peter Falus
- Institut Max von Laue-Paul Langevin (ILL), 71 avenue des Martyrs, CS 20156, Cedex 9, F-38042Grenoble, France
| | - Michael Monkenbusch
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425Jülich, Germany
| | - Dieter Richter
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425Jülich, Germany
| |
Collapse
|
7
|
Anomalous Dynamics in Macromolecular Liquids. Polymers (Basel) 2022; 14:polym14050856. [PMID: 35267678 PMCID: PMC8912788 DOI: 10.3390/polym14050856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 02/06/2022] [Accepted: 02/18/2022] [Indexed: 02/01/2023] Open
Abstract
Macromolecular liquids display short-time anomalous behaviors in disagreement with conventional single-molecule mean-field theories. In this study, we analyze the behavior of the simplest but most realistic macromolecular system that displays anomalous dynamics, i.e., a melt of short homopolymer chains, starting from molecular dynamics simulation trajectories. Our study sheds some light on the microscopic molecular mechanisms responsible for the observed anomalous behavior. The relevance of the correlation hole, a unique property of polymer liquids, in relation to the observed subdiffusive dynamics, naturally emerges from the analysis of the van Hove distribution functions and other properties.
Collapse
|
8
|
Kruteva M, Zamponi M, Hoffmann I, Allgaier J, Monkenbusch M, Richter D. Non-Gaussian and Cooperative Dynamics of Entanglement Strands in Polymer Melts. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Margarita Kruteva
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425 Jülich, Germany
| | - Michaela Zamponi
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstraße 1, 85748 Garching, Germany
| | - Ingo Hoffmann
- Institut Laue-Langevin (ILL), B.P. 156, F-38042 Grenoble Cedex 9, France
| | - Jürgen Allgaier
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425 Jülich, Germany
| | - Michael Monkenbusch
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425 Jülich, Germany
| | - Dieter Richter
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1: Neutron Scattering and Biological Matter), 52425 Jülich, Germany
| |
Collapse
|
9
|
Zamponi M, Kruteva M, Monkenbusch M, Willner L, Wischnewski A, Hoffmann I, Richter D. Cooperative Chain Dynamics of Tracer Chains in Highly Entangled Polyethylene Melts. PHYSICAL REVIEW LETTERS 2021; 126:187801. [PMID: 34018790 DOI: 10.1103/physrevlett.126.187801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
By neutron spin echo spectroscopy, we have studied the center of mass motion of short tracer chains on the molecular length scale within a highly entangled polymer matrix. The center of mass mean square displacements of the tracers independent of their molecular weight is subdiffusive at short times until it has reached the size of the tube d; then, a crossover to Fickian diffusion takes place. This observation cannot be understood within the tube model of reptation, but is rationalized as a result of important interchain couplings that lead to cooperative chain motion within the entanglement volume ∼d^{3}. Thus, the cooperative tracer chain motions are limited by the tube size d. If the center of mass displacement exceeds this size, uncorrelated Fickian diffusion takes over. Compared to the prediction of the Rouse model we observe a significantly reduced contribution of the tracer's internal modes to the spectra corroborating the finding of cooperative rather than Rouse dynamics within d^{3}.
Collapse
Affiliation(s)
- M Zamponi
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstraße 1, 85748 Garching, Germany
| | - M Kruteva
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), 52425 Jülich, Germany
| | - M Monkenbusch
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), 52425 Jülich, Germany
| | - L Willner
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), 52425 Jülich, Germany
| | - A Wischnewski
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), 52425 Jülich, Germany
| | - I Hoffmann
- Institut Laue-Langevin (ILL), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - D Richter
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), 52425 Jülich, Germany
| |
Collapse
|
10
|
Arbe A, Alvarez F, Colmenero J. Insight into the Structure and Dynamics of Polymers by Neutron Scattering Combined with Atomistic Molecular Dynamics Simulations. Polymers (Basel) 2020; 12:E3067. [PMID: 33371357 PMCID: PMC7767341 DOI: 10.3390/polym12123067] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 11/23/2022] Open
Abstract
Combining neutron scattering and fully atomistic molecular dynamics simulations allows unraveling structural and dynamical features of polymer melts at different length scales, mainly in the intermolecular and monomeric range. Here we present the methodology developed by us and the results of its application during the last years in a variety of polymers. This methodology is based on two pillars: (i) both techniques cover approximately the same length and time scales and (ii) the classical van Hove formalism allows easily calculating the magnitudes measured by neutron scattering from the simulated atomic trajectories. By direct comparison with experimental results, the simulated cell is validated. Thereafter, the information of the simulations can be exploited, calculating magnitudes that are experimentally inaccessible or extending the parameters range beyond the experimental capabilities. We show how detailed microscopic insight on structural features and dynamical processes of various kinds has been gained in polymeric systems with different degrees of complexity, and how intriguing questions as the collective behavior at intermediate length scales have been faced.
Collapse
Affiliation(s)
- Arantxa Arbe
- Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (A.A.); (F.A.)
| | - Fernando Alvarez
- Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (A.A.); (F.A.)
- Departamento de Polímeros y Materiales Avanzados, Física, Química y Tecnología (UPV/EHU), Apartado 1072, E-20080 San Sebastián, Spain
| | - Juan Colmenero
- Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (A.A.); (F.A.)
- Departamento de Polímeros y Materiales Avanzados, Física, Química y Tecnología (UPV/EHU), Apartado 1072, E-20080 San Sebastián, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, E-20018 San Sebastián, Spain
| |
Collapse
|
11
|
Kruteva M, Monkenbusch M, Allgaier J, Holderer O, Pasini S, Hoffmann I, Richter D. Self-Similar Dynamics of Large Polymer Rings: A Neutron Spin Echo Study. PHYSICAL REVIEW LETTERS 2020; 125:238004. [PMID: 33337173 DOI: 10.1103/physrevlett.125.238004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 09/29/2020] [Indexed: 06/12/2023]
Abstract
This work clarifies the self-similar dynamics of large polymer rings using pulsed-field gradient nuclear magnetic resonance and neutron spin echo spectroscopy. We find center of mass diffusion taking place in three dynamic regimes starting (i) with a strongly subdiffusive domain ⟨r^{2}(t)⟩_{com}∼t^{α} (0.4≤α≤0.65); (ii) a second subdiffusive region ⟨r^{2}(t)⟩_{com}∼t^{0.75} that (iii) finally crosses over to Fickian diffusion. While the t^{0.75} range previously has been found in simulations and was predicted by theory, we attribute the first to the effect of cooperative dynamics resulting from the correlation hole potential. The internal dynamics at scales below the elementary loop size is well described by ring Rouse motion. At larger scales the dynamics is self-similar and follows very well the predictions of the scaling models with preference for the self-consistent fractal loopy globule model.
Collapse
Affiliation(s)
- M Kruteva
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), 52425 Jülich, Germany
| | - M Monkenbusch
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), 52425 Jülich, Germany
| | - J Allgaier
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), 52425 Jülich, Germany
| | - O Holderer
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstraße 1, 85748 Garching, Germany
| | - S Pasini
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstraße 1, 85748 Garching, Germany
| | - I Hoffmann
- Institut Laue-Langevin (ILL), 71 avenue des Martyrs, 38000 Grenoble, France
| | - D Richter
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), 52425 Jülich, Germany
| |
Collapse
|
12
|
Mei B, Dell ZE, Schweizer KS. Microscopic Theory of Long-Time Center-of-Mass Self-Diffusion and Anomalous Transport in Ring Polymer Liquids. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01737] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Baicheng Mei
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
| | - Zachary E. Dell
- Department of Physics, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
| | - Kenneth S. Schweizer
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
- Department of Chemical & Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
| |
Collapse
|
13
|
Abstract
We review recent neutron scattering work and related results from simulation and complementary techniques focusing on the microscopic dynamics of polymers under confinement. Confinement is either realized in model porous materials or in polymer nanocomposites (PNC). The dynamics of such confined polymers is affected on the local segmental level, the level of entanglements as well as on global levels: (i) at the segmental level the interaction with the surface is of key importance. At locally repulsive surfaces compared to the bulk the segmental dynamics is not altered. Attractive surfaces slow down the segmental dynamics in their neighborhood but do not give rise to dead, glassy layers. (ii) Confinement generally has little effect on the inter-chain entanglements: both for weakly as well as for marginally confined polymers the reptation tube size is not changed. Only for strongly confined polymers disentanglement takes place. Similarly, in PNC at higher NP loading disentanglement phenomena are observed; in addition, at very high loading a transition from polymer caused topological constraints to purely geometrical constraints is observed. (iii) On the more global scale NSE experiments revealed important information on the nature of the interphase between adsorbed layer and bulk polymer. (iv) Polymer grafts at NP mutually confine each other, an effect that is most pronounced for one component NP. (v) Global diffusion of entangled polymers both in weakly and strongly attractive PNC is governed by the ratio of bottle-neck to chain size that characterizes the 'entropic barrier' for global diffusion.
Collapse
Affiliation(s)
- Dieter Richter
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Complex Systems (ICS-1), Forschungszentrum Jülich GmbH, Jülich, Germany.
| | | |
Collapse
|
14
|
Guenza MG, Dinpajooh M, McCarty J, Lyubimov IY. Accuracy, Transferability, and Efficiency of Coarse-Grained Models of Molecular Liquids. J Phys Chem B 2018; 122:10257-10278. [DOI: 10.1021/acs.jpcb.8b06687] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. G. Guenza
- Department of Chemistry and Biochemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
| | - M. Dinpajooh
- Department of Chemistry and Biochemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
| | - J. McCarty
- Department of Chemistry and Biochemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
| | - I. Y. Lyubimov
- Department of Chemistry and Biochemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, United States
| |
Collapse
|
15
|
Zulli F, Giordano M, Andreozzi L. Chain-Length Dependence of Relaxation and Dynamics in Poly(methyl methacrylate) from Oligomers to Polymers. Macromolecules 2018. [DOI: 10.1021/acs.macromol.7b02330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fabio Zulli
- Department of Physics “E. Fermi”, University of Pisa and IPCF-CNR, Pisa, Italy
| | - Marco Giordano
- Department of Physics “E. Fermi”, University of Pisa and IPCF-CNR, Pisa, Italy
| | - Laura Andreozzi
- Department of Physics “E. Fermi”, University of Pisa and IPCF-CNR, Pisa, Italy
| |
Collapse
|
16
|
Ramos J, Vega J, Martínez-Salazar J. Predicting experimental results for polyethylene by computer simulation. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2017.12.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
17
|
Deng B, Huang L, Shi Y. Solvent Effect on the Diffusion of Unentangled Linear Polymer Melts. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11845-11850. [PMID: 28930634 DOI: 10.1021/acs.langmuir.7b02901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We conducted molecular dynamics (MD) simulations to study how solvent chains affect the diffusion of linear polymers in the unentangled regime. For monodisperse solvent chains, the self-diffusivity of a tagged chain scales with its chain length. The solvent chain length affects both the prefactor and the exponent, the latter of which ranges from -0.79 to -0.85. The scaling exponent here deviates from -1 as predicted by the Rouse model, which may suggest that the friction coefficient increases with the solvent chain length. In addition, we carried out diffusion simulations on two polydisperse melts, one with the Flory-Schulz distribution and the other with the Gaussian distribution. The measured diffusivity as a function of the tagged chain length agrees with a simple proposed model accounting for the heterogeneous medium.
Collapse
Affiliation(s)
- Binghui Deng
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Liping Huang
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Yunfeng Shi
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| |
Collapse
|
18
|
|
19
|
Ramos J, Vega JF, Martínez-Salazar J. A new insight into the conformation and melt dynamics of hydrogenated polybutadiene as revealed by computer simulations. SOFT MATTER 2016; 12:3929-3936. [PMID: 27003544 DOI: 10.1039/c5sm03080c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Extensive molecular dynamics simulations of the macromolecular conformation and the melt dynamics for model polymers of different molecular weights have been carried out. The selected models are hydrogenated polybutadienes with a 2% content of ethyl branches and linear polyethylene. It will be shown that the density and chain stiffness are clearly affected by both the molecular weight and the presence of ethyl branches. Furthermore, the results obtained from the simulations on the molecular size and, more remarkably, chain dynamics, perfectly match the neutron scattering experiments performed by Zamponi et al. in hydrogenated polybutadienes. We observe a clear chain contraction and a slow dynamics for the hydrogenated polybutadiene with respect to the linear chain of the same molecular length. Using the Likhtman-McLeish definitions, the obtained values of the entanglement relaxation time (τe) and the tube diameter (a) are found to be in agreement with the available experimental data (by rheology and neutron spin echo) as well as with those obtained by the simulations. Finally, a very good agreement of diffusion coefficients as a function of the molecular weight between simulations and experiments is observed. Therefore, there exists a clear difference between the results obtained for branched and linear polyethylene, accounting for a definitive effect of the short chain branching on the conformational properties and the melt dynamics of polyolefins.
Collapse
Affiliation(s)
- Javier Ramos
- Biophym, Departamento de Física Macromolecular, Instituto de Estructura de la Materia, CSIC, c/Serrano 113 bis, 28006 Madrid, Spain.
| | | | | |
Collapse
|
20
|
Sliozberg YR, Kröger M, Chantawansri TL. Fast equilibration protocol for million atom systems of highly entangled linear polyethylene chains. J Chem Phys 2016; 144:154901. [DOI: 10.1063/1.4946802] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yelena R. Sliozberg
- U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA
- TKC Global, Inc., Aberdeen Proving Ground, Maryland 21005, USA
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zürich, Leopold-Ruzicka-Weg 4, CH-8093 Zürich, Switzerland
| | | |
Collapse
|
21
|
Richter D, Goossen S, Wischnewski A. Celebrating Soft Matter's 10th Anniversary: Topology matters: structure and dynamics of ring polymers. SOFT MATTER 2015; 11:8535-8549. [PMID: 26406787 DOI: 10.1039/c5sm01994j] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Considering topology among all polymer architectures polymer rings are unique, as they are the simplest closed structures without ends. In this review we present recent experimental advances addressing the structure and dynamics of rings. We focus mainly on neutron scattering results that reveal experimental insight on a molecular scale. We first briefly reflect on the progress in ring chemistry that made the experimental access possible. Structural investigations characterizing rings as compact objects in the melts are put into theoretical context. In contrast to the plateau regime common for all other high molecular weight polymer systems, the dynamic modulus of pure ring systems is characterized by a power law decay, while the viscosity displays a much weaker molecular weight dependence as a corresponding linear melt. The dynamics of ring melts is uniquely addressed by neutron spin-echo spectroscopy. The sub-diffusive center of mass motion at short times agrees well with simulation as well as theoretical concepts. In the internal dynamics the basic length scale of the ring molecule, the loop size, manifests itself clearly. The experiments reveal strong evidence for loop motions and call for further theoretical work describing them. Finally, small fractions of ring molecules in linear melts turn out to be very sensitive probes in order to scrutinize the dynamics of the host with the potential to reveal fundamental aspects of the dynamics of branched polymer systems.
Collapse
Affiliation(s)
- D Richter
- Jülich Centre for Neutron Science, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - S Goossen
- Jülich Centre for Neutron Science, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - A Wischnewski
- Jülich Centre for Neutron Science, Forschungszentrum Jülich, 52425 Jülich, Germany.
| |
Collapse
|
22
|
Ramos J, Vega JF, Martínez-Salazar J. Molecular Dynamics Simulations for the Description of Experimental Molecular Conformation, Melt Dynamics, and Phase Transitions in Polyethylene. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00823] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Javier Ramos
- Biophym, Departamento de
Física Macromolecular, Instituto de Estructura de la Materia, IEM-CSIC, C/Serrano 113 bis, 28006 Madrid, Spain
| | - Juan F. Vega
- Biophym, Departamento de
Física Macromolecular, Instituto de Estructura de la Materia, IEM-CSIC, C/Serrano 113 bis, 28006 Madrid, Spain
| | - Javier Martínez-Salazar
- Biophym, Departamento de
Física Macromolecular, Instituto de Estructura de la Materia, IEM-CSIC, C/Serrano 113 bis, 28006 Madrid, Spain
| |
Collapse
|
23
|
Panja D, Barkema GT, Ball RC. Complex Interactions with the Surroundings Dictate a Tagged Chain’s Dynamics in Unentangled Polymer Melts. Macromolecules 2015. [DOI: 10.1021/ma502523p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Debabrata Panja
- Institute
of Physics, Universiteit van Amsterdam, Science Park 904, Postbus 94485, 1090
GL Amsterdam, The Netherlands
| | - Gerard T. Barkema
- Institute
for Theoretical Physics, Universiteit Utrecht, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands
- Instituut-Lorentz, Universiteit Leiden,
Niels Bohrweg 2, 2333 CA, Leiden, The Netherlands
| | - Robin C. Ball
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K
| |
Collapse
|
24
|
Diddens D, Heuer A. Chain end mobilities in polymer melts--a computational study. J Chem Phys 2015; 142:014906. [PMID: 25573582 DOI: 10.1063/1.4905238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Rouse model can be regarded as the standard model to describe the dynamics of a short polymer chain under melt conditions. In this contribution, we explicitly check one of the fundamental assumptions of this model, namely, that of a uniform friction coefficient for all monomers, on the basis of MD simulation data of a poly(ethylene oxide) (PEO) melt. This question immediately arises from the fact that in a real polymer melt, the terminal monomers have on average more intermolecular neighbors than the central monomers, and one would expect that exactly these details affect the precise value of the friction coefficient. The mobilities are determined by our recently developed statistical method, which provides detailed insights into the local polymer dynamics. Moreover, it yields complementary information to that obtained from the mean square displacement (MSD) or the Rouse mode analysis. It turns out that the Rouse assumption of a uniform mobility is fulfilled to a good approximation for the PEO melt. However, a more detailed analysis reveals that the underlying microscopic dynamics are highly affected by different contributions from intra- and intermolecular excluded volume interactions, which cannot be taken into account by a modified friction coefficient. Minor deviations occur only for the terminal monomers on larger time scales, which can be attributed to the presence of two different escape mechanisms from their first coordination sphere. These effects remain elusive when studying the dynamics with the MSD only.
Collapse
Affiliation(s)
- Diddo Diddens
- Institute of Physical Chemistry, University of Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - Andreas Heuer
- Institute of Physical Chemistry, University of Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| |
Collapse
|
25
|
Ngai KL, Plazek DJ. Thermo-Rheological, Piezo-Rheological, and TVγ-Rheological Complexities of Viscoelastic Mechanisms in Polymers. Macromolecules 2014. [DOI: 10.1021/ma501843u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K. L. Ngai
- Dipartimento
di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
- CNR-IPCF, Largo B. Pontecorvo 3, I-56127, Pisa, Italy
| | - D. J. Plazek
- Department of Mechanical
Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261United States
| |
Collapse
|
26
|
Kalathi JT, Kumar SK, Rubinstein M, Grest GS. Rouse Mode Analysis of Chain Relaxation in Homopolymer Melts. Macromolecules 2014; 47:6925-6931. [PMID: 25328247 PMCID: PMC4196748 DOI: 10.1021/ma500900b] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/31/2014] [Indexed: 11/29/2022]
Abstract
![]()
We use molecular dynamics simulations
of the Kremer–Grest
(KG) bead–spring model of polymer chains of length between
10 and 500, and a closely related analogue that allows for chain crossing,
to clearly delineate the effects of entanglements on the length-scale-dependent
chain relaxation in polymer melts. We analyze the resulting trajectories
using the Rouse modes of the chains and find that entanglements strongly
affect these modes. The relaxation rates of the chains show two limiting
effective monomeric frictions, with the local modes experiencing much
lower effective friction than the longer modes. The monomeric relaxation
rates of longer modes vary approximately inversely with chain length
due to kinetic confinement effects. The time-dependent relaxation
of Rouse modes has a stretched exponential character with a minimum
of stretching exponent in the vicinity of the entanglement chain length.
None of these trends are found in models that allow for chain crossing.
These facts, in combination, argue for the confined motion of chains
for time scales between the entanglement time and their ultimate free
diffusion.
Collapse
Affiliation(s)
- Jagannathan T Kalathi
- Department of Chemical Engineering, Columbia University , New York, New York 10027, United States
| | - Sanat K Kumar
- Department of Chemical Engineering, Columbia University , New York, New York 10027, United States
| | - Michael Rubinstein
- Department of Chemistry, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Gary S Grest
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| |
Collapse
|
27
|
Brás AR, Goossen S, Krutyeva M, Radulescu A, Farago B, Allgaier J, Pyckhout-Hintzen W, Wischnewski A, Richter D. Compact structure and non-Gaussian dynamics of ring polymer melts. SOFT MATTER 2014; 10:3649-3655. [PMID: 24667976 DOI: 10.1039/c3sm52717d] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a neutron scattering analysis of the structure and dynamics of PEO polymer rings with a molecular weight 2.5 times higher than the entanglement mass. The melt structure was found to be more compact than a Gaussian model would suggest. With increasing time the center of mass (c.o.m.) diffusion undergoes a transition from sub-diffusive to diffusive behavior. The transition time agrees well with the decorrelation time predicted by a mode coupling approach. As a novel feature well pronounced non-Gaussian behavior of the c.o.m. diffusion was found that shows surprising analogies to the cage effect known from glassy systems. Finally, the longest wavelength Rouse modes are suppressed possibly as a consequence of an onset of lattice animal features as hypothesized in theoretical approaches.
Collapse
Affiliation(s)
- Ana R Brás
- Jülich Centre for Neutron Science JCNS (JCNS-1) and Institute for Complex Systems (ICS), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Guenza MG. Localization of chain dynamics in entangled polymer melts. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:052603. [PMID: 25353822 DOI: 10.1103/physreve.89.052603] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Indexed: 06/04/2023]
Abstract
The dynamics of polymer melts in both the unentangled and entangled regimes is described by a Langevin equation for the correlated motion of a group of chains, interacting through both intra- and inter-molecular potentials. Entanglements are represented by an intermolecular monomer-monomer confining potential that has no effect on short chains, while interpolymer interactions, responsible for correlated motion and subdiffusive center-of-mass dynamics, are represented by an intermolecular center-of-mass potential derived from the Ornstein-Zernike equation. This potential ensures that the liquid of phantom chains reproduces the compressibility and free energy of the real samples. For polyethylene melts the calculated dynamic structure factor is found to be in quantitative agreement with neutron spin echo experiments of polyethylene melts with chain lengths that span both the unentangled and the entangled regimes. The theory shows a progressive localization of the cooperative chain dynamics at the crossover from the unentangled to the entangled regime, in the spirit of the reptation model.
Collapse
Affiliation(s)
- M G Guenza
- Department of Chemistry and Biochemistry, and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, USA
| |
Collapse
|
29
|
Ngai KL, Capaccioli S. Response to “Comment on ‘Unified explanation of the anomalous dynamic properties of highly asymmetric polymer blends’ ” [J. Chem. Phys. 138, 197101 (2013)]. J Chem Phys 2013; 138:197102. [DOI: 10.1063/1.4804625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
30
|
Lyubimov IY, Guenza MG. Theoretical reconstruction of realistic dynamics of highly coarse-grained cis-1,4-polybutadiene melts. J Chem Phys 2013; 138:12A546. [DOI: 10.1063/1.4792367] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
31
|
Ngai KL, Capaccioli S. Unified explanation of the anomalous dynamic properties of highly asymmetric polymer blends. J Chem Phys 2013; 138:054903. [DOI: 10.1063/1.4789585] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
32
|
Colmenero J, Arbe A. Recent progress on polymer dynamics by neutron scattering: From simple polymers to complex materials. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/polb.23178] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
33
|
Farago J, Meyer H, Baschnagel J, Semenov AN. Hydrodynamic and viscoelastic effects in polymer diffusion. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:284105. [PMID: 22738798 DOI: 10.1088/0953-8984/24/28/284105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We develop a fluctuating hydrodynamics approach to study the impact of the hydrodynamic and viscoelastic interactions on the motion of the center of mass of a polymer as well as on the relaxation of Rouse modes, either in a Θ solvent or in a melt of identical unentangled chains. We show that this method allows us to describe the effect of hydrodynamic interactions beyond the Zimm (for a single chain in a Θ solvent) or the Rouse models (for an unentangled melt). In the latter case, we recover the same important effect of the viscoelastic hydrodynamic interactions on the center-of-mass diffusion, first described in Farago et al (2011 Phys. Rev. Lett. 107 178301).
Collapse
Affiliation(s)
- J Farago
- Institut Charles Sadron, Université de Strasbourg, CNRS UPR22, 22 rue du Loess, BP 84047, F-67034 Strasbourg, France.
| | | | | | | |
Collapse
|
34
|
Farago J, Semenov AN, Meyer H, Wittmer JP, Johner A, Baschnagel J. Mode-coupling approach to polymer diffusion in an unentangled melt. I. The effect of density fluctuations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:051806. [PMID: 23004780 DOI: 10.1103/physreve.85.051806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Indexed: 06/01/2023]
Abstract
We quantitatively assess the effect of density fluctuation modes on the dynamics of a tagged polymer in an unentangled melt. To this end, we develop a density-based mode-coupling theory (dMCT) using the Mori-Zwanzig approach and projecting the fluctuating force onto pair-density fluctuation modes. The effect of dynamical density fluctuations on the center-of-mass (c.m.) dynamics is also analyzed based on a perturbative approach and we show that dMCT and perturbation techniques yield identical results. The c.m. velocity autocorrelation function (c.m. VAF) exhibits a slow power law relaxation in the time range between the monomer time t_{1} and the Rouse relaxation time t_{N}. We obtain an analytical expression for the c.m. VAF in terms of molecular parameters. In particular, the c.m. VAF scales as -N^{-1}t^{-5/4} (where N is the number of monomer units per chain) in the relevant time regime. The results are qualitatively accounted for by the dynamical correlation hole effect. The predicted -t^{-5/4} dependence of the c.m. VAF is supported by data of non-momentum-conserving computer simulations. However, the comparison shows that the theory significantly underestimates the amplitude of the effect. This issue is discussed and an alternative approach is addressed in the second part of this series [Farago et al., Phys. Rev. E 85, 051807 (2012), the following paper].
Collapse
Affiliation(s)
- J Farago
- Institut Charles Sadron, Université de Strasbourg, CNRS UPR22, 23 rue du Loess, 67034 Strasbourg Cedex 2, France
| | | | | | | | | | | |
Collapse
|
35
|
Ngai KL, Wang LM. Interchain coupled chain dynamics of poly(ethylene oxide) in blends with poly(methyl methacrylate): coupling model analysis. J Chem Phys 2011; 135:194902. [PMID: 22112097 DOI: 10.1063/1.3662130] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quasielastic neutron scattering and molecular dynamics simulation data from poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA) blends found that for short times the self-dynamics of PEO chain follows the Rouse model, but at longer times past t(c) = 1-2 ns it becomes slower and departs from the Rouse model in dependences on time, momentum transfer, and temperature. To explain the anomalies, others had proposed the random Rouse model (RRM) in which each monomer has different mobility taken from a broad log-normal distribution. Despite the success of the RRM, Diddens et al. [Eur. Phys. Lett. 95, 56003 (2011)] extracted the distribution of friction coefficients from the MD simulations of a PEO/PMMA blend and found that the distribution is much narrower than expected from the RRM. We propose a simpler alternative explanation of the data by utilizing alone the observed crossover of PEO chain dynamics at t(c). The present problem is just a special case of a general property of relaxation in interacting systems, which is the crossover from independent relaxation to coupled many-body relaxation at some t(c) determined by the interaction potential and intermolecular coupling/constraints. The generality is brought out vividly by pointing out that the crossover also had been observed by neutron scattering from entangled chains relaxation in monodisperse homopolymers, and from the segmental α-relaxation of PEO in blends with PMMA. The properties of all the relaxation processes in connection with the crossover are similar, despite the length scales of the relaxation in these systems are widely different.
Collapse
Affiliation(s)
- K L Ngai
- CNR-IPCF, Dipartimento di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy.
| | | |
Collapse
|
36
|
|
37
|
Lyubimov I, Guenza MG. First-principle approach to rescale the dynamics of simulated coarse-grained macromolecular liquids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:031801. [PMID: 22060394 DOI: 10.1103/physreve.84.031801] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 06/23/2011] [Indexed: 05/31/2023]
Abstract
We present a detailed derivation and testing of our approach to rescale the dynamics of mesoscale simulations of coarse-grained polymer melts (I. Y. Lyubimov, J. McCarty, A. Clark, and M. G. Guenza, J. Chem. Phys. 132, 224903 (2010)). Starting from the first-principle Liouville equation and applying the Mori-Zwanzig projection operator technique, we derive the generalized Langevin equations (GLEs) for the coarse-grained representations of the liquid. The chosen slow variables in the projection operators define the length scale of coarse graining. Each polymer is represented at two levels of coarse graining: monomeric as a bead-and-spring model and molecular as a soft colloid. In the long-time regime where the center-of-mass follows Brownian motion and the internal dynamics is completely relaxed, the two descriptions must be equivalent. By enforcing this formal relation we derive from the GLEs the analytical rescaling factors to be applied to dynamical data in the coarse-grained representation to recover the monomeric description. Change in entropy and change in friction are the two corrections to be accounted for to compensate the effects of coarse graining on the polymer dynamics. The solution of the memory functions in the coarse-grained representations provides the dynamical rescaling of the friction coefficient. The calculation of the internal degrees of freedom provides the correction of the change in entropy due to coarse graining. The resulting rescaling formalism is a function of the coarse-grained model and thermodynamic parameters of the system simulated. The rescaled dynamics obtained from mesoscale simulations of polyethylene, represented as soft-colloidal particles, by applying our rescaling approach shows a good agreement with data of translational diffusion measured experimentally and from simulations. The proposed method is used to predict self-diffusion coefficients of new polyethylene samples.
Collapse
Affiliation(s)
- I Lyubimov
- Department of Chemistry and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, USA
| | | |
Collapse
|
38
|
Pérez-Aparicio R, Alvarez F, Arbe A, Willner L, Richter D, Falus P, Colmenero J. Chain Dynamics of Unentangled Poly(ethylene-alt-propylene) Melts by Means of Neutron Scattering and Fully Atomistic Molecular Dynamics Simulations. Macromolecules 2011. [DOI: 10.1021/ma102909r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. Pérez-Aparicio
- Departamento de Física de Materiales UPV/EHU, Apartado 1072, 20080 San Sebastián, Spain
| | - F. Alvarez
- Departamento de Física de Materiales UPV/EHU, Apartado 1072, 20080 San Sebastián, Spain
- Centro de Física de Materiales (CSIC−UPV/EHU), Materials Physics Center (MPC), Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - A. Arbe
- Centro de Física de Materiales (CSIC−UPV/EHU), Materials Physics Center (MPC), Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - L. Willner
- Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D−52425 Jülich, Germany
| | - D. Richter
- Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D−52425 Jülich, Germany
| | - P. Falus
- Institut Laue Langevin, BP 156, 38042 Grenoble Cedex 9, France
| | - J. Colmenero
- Departamento de Física de Materiales UPV/EHU, Apartado 1072, 20080 San Sebastián, Spain
- Centro de Física de Materiales (CSIC−UPV/EHU), 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
| |
Collapse
|
39
|
Andreozzi L, Faetti M, Giordano M, Zulli F. Length scales and dynamics in the reorientational relaxation of tracers in molecular and polymeric glass formers via electron spin resonance spectroscopy. J Phys Chem B 2010; 114:12833-9. [PMID: 20860386 DOI: 10.1021/jp106798c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is widely accepted that a temperature region exists above the glass transition temperature, playing a fundamental role in the physics of polymers and glass formers. In this region, several dynamic crossovers have been experimentally and numerically revealed in the past years and the onset of glassy behavior is generally located, because of cooperative and heterogeneous features exhibited by the dynamics. In this Article, the rotational dynamics of two different stiff molecular spin probes dissolved in poly(propylene glycol) has been investigated by electron spin resonance spectroscopy in a wide temperature range. Decoupling phenomena between macroscopic and microscopic transport properties have been observed in the crossover region. A comparison with previous studies carried out with the same tracers dissolved in different polymers and glass formers strongly supports the idea that the observed crossover signals the onset of spatial correlations of dynamics on the length scale probed by the tracers.
Collapse
Affiliation(s)
- Laura Andreozzi
- Dipartimento di Fisica Enrico Fermi, Università di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
| | | | | | | |
Collapse
|
40
|
Chan NY, Dunstan DE. The thermodynamics of polymer mixing and compression in the semidilute regime. J Phys Chem B 2010; 114:10520-3. [PMID: 20666451 DOI: 10.1021/jp101793c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polymers present a fascinating range of mechanical properties in the extension, compression, and flow of soft condensed matter. Entropy determines the physics of the elastic material behavior of polymeric systems in deformation. Classical models of polymer dynamics have assumed chain entanglement and resulting reptation in concentrated polymer solutions. Here, we present a thermodynamic treatment of interacting chains in solution with increasing concentration from the dilute to concentrated regimes. As the polymer chain concentration increases above the critical overlap, the chains must either compress or overlap and entangle, resulting in a decrease in chain configurational entropy. The free energy of chain entanglement is shown to be less favored than compression at concentrations above the critical overlap. Elastic forces act on the chains to reduce the dimensions to the ideal random walk size with increasing concentration. At significantly higher concentrations, the free energies reach an asymptote where chain compression and entanglement are simultaneously possible. Entanglement and reptation are shown to be statistically improbable in the semidilute regime, and it is concluded that the compression of polymer chains is favored at semidilute concentrations.
Collapse
Affiliation(s)
- Nikko Y Chan
- Department of Chemical and Biomolecular Engineering, University of Melbourne, VIC 3010, Australia
| | | |
Collapse
|
41
|
Lyubimov IY, McCarty J, Clark A, Guenza MG. Analytical rescaling of polymer dynamics from mesoscale simulations. J Chem Phys 2010; 132:224903. [DOI: 10.1063/1.3450301] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
42
|
Durand M, Meyer H, Benzerara O, Baschnagel J, Vitrac O. Molecular dynamics simulations of the chain dynamics in monodisperse oligomer melts and of the oligomer tracer diffusion in an entangled polymer matrix. J Chem Phys 2010; 132:194902. [DOI: 10.1063/1.3420646] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
43
|
Dolgushev M, Blumen A. Dynamics of chains and dendrimers with heterogeneous semiflexibility. J Chem Phys 2010; 132:124905. [DOI: 10.1063/1.3366662] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
44
|
Brodeck M, Alvarez F, Moreno AJ, Colmenero J, Richter D. Chain Motion in Nonentangled Dynamically Asymmetric Polymer Blends: Comparison between Atomistic Simulations of PEO/PMMA and a Generic Bead−Spring Model. Macromolecules 2010. [DOI: 10.1021/ma902820a] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martin Brodeck
- Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Fernando Alvarez
- Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastian, Spain
- Departamento de Física de Materiales
| | - Angel J. Moreno
- Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastian, Spain
| | - Juan Colmenero
- Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastian, Spain
- Departamento de Física de Materiales
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain
| | - Dieter Richter
- Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| |
Collapse
|
45
|
Karayiannis NC, Kröger M. Combined molecular algorithms for the generation, equilibration and topological analysis of entangled polymers: methodology and performance. Int J Mol Sci 2009; 10:5054-5089. [PMID: 20087477 PMCID: PMC2808023 DOI: 10.3390/ijms10115054] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 11/17/2009] [Accepted: 11/20/2009] [Indexed: 12/02/2022] Open
Abstract
We review the methodology, algorithmic implementation and performance characteristics of a hierarchical modeling scheme for the generation, equilibration and topological analysis of polymer systems at various levels of molecular description: from atomistic polyethylene samples to random packings of freely-jointed chains of tangent hard spheres of uniform size. Our analysis focuses on hitherto less discussed algorithmic details of the implementation of both, the Monte Carlo (MC) procedure for the system generation and equilibration, and a postprocessing step, where we identify the underlying topological structure of the simulated systems in the form of primitive paths. In order to demonstrate our arguments, we study how molecular length and packing density (volume fraction) affect the performance of the MC scheme built around chain-connectivity altering moves. In parallel, we quantify the effect of finite system size, of polydispersity, and of the definition of the number of entanglements (and related entanglement molecular weight) on the results about the primitive path network. Along these lines we approve main concepts which had been previously proposed in the literature.
Collapse
Affiliation(s)
- Nikos Ch. Karayiannis
- Institute for Optoelectronics and Microsystems (ISOM) and ETSII, Universidad Politécnica de Madrid (UPM), José Gutiérrez Abascal 2, E-28006 Madrid, Spain
| | - Martin Kröger
- Polymer Physics, Swiss Federal Institute of Technology, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8049 Zurich, Switzerland
| |
Collapse
|
46
|
Dolgushev M, Blumen A. Dynamics of semiflexible treelike polymeric networks. J Chem Phys 2009; 131:044905. [DOI: 10.1063/1.3184797] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
47
|
Affiliation(s)
- Maxim Dolgushev
- Theoretical Polymer Physics, University of Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg, Germany
| | - Alexander Blumen
- Theoretical Polymer Physics, University of Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg, Germany
| |
Collapse
|
48
|
Brodeck M, Alvarez F, Arbe A, Juranyi F, Unruh T, Holderer O, Colmenero J, Richter D. Study of the dynamics of poly(ethylene oxide) by combining molecular dynamic simulations and neutron scattering experiments. J Chem Phys 2009; 130:094908. [DOI: 10.1063/1.3077858] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|