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Zheng Y, Tsige M, Wang SQ. Molecular Dynamics Simulation of Entangled Melts at High Rates: Identifying Entanglement Lockup Mechanism Leading to True Strain Hardening. Macromol Rapid Commun 2023; 44:e2200159. [PMID: 35881534 DOI: 10.1002/marc.202200159] [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: 02/20/2022] [Revised: 06/20/2022] [Indexed: 01/11/2023]
Abstract
In the present work, molecular dynamics simulations are carried out based on the bead-spring model to indicate how the entanglement lockup manifests in the late stage of fast Rouse-Weissnberg number (WiR >>1) uniaxial melt stretching of entangled polymer melts. At high strains, distinct features show up to reveal the emergence of an increasingly tightened entanglement network. Chain tension can build up, peaking at the middle of the chain, to a level for chain scission, through accumulated interchain interactions, as if there is a tug-of-war ongoing for each load-bearing chain. Thanks to the interchain uncrossability, network junctions form by the pairing of two or more hairpins. It is hypothesized that the interchain entanglement at junctions can lockup through prevailing twist-like interchain couplings as long as WiR > 9. In this limit, a significant fraction of chains act like cyclic chains to form a network held by interchain uncrossability, and appreciable chain tension emerges.
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Affiliation(s)
- Yexin Zheng
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, OH, 44325, USA
| | - Mesfin Tsige
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, OH, 44325, USA
| | - Shi-Qing Wang
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, OH, 44325, USA
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Kirk J, Wang Z, Ilg P. Entanglement dynamics at flat surfaces: Investigations using multi-chain molecular dynamics and a single-chain slip-spring model. J Chem Phys 2019; 150:094906. [PMID: 30849883 DOI: 10.1063/1.5045301] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dynamics of an entangled polymer melt confined in a channel by parallel plates is investigated by Molecular Dynamics (MD) simulations of a detailed, multi-chain model. A primitive path analysis predicts that the density of entanglements remains approximately constant throughout the gap and drops to lower values only in the immediate vicinity of the surface. Based on these observations, we propose a coarse-grained, single-chain slip-spring model with a uniform density of slip-spring anchors and slip-links. The slip-spring model is compared to the Kremer-Grest MD bead-spring model via equilibrium correlation functions of chain orientations. Reasonably good agreement between the single-chain model and the detailed multi-chain model is obtained for chain relaxation dynamics, both away from the surface and for chains whose center of mass positions are at a distance from the surface that is less than the bulk chain radius of gyration, without introducing any additional model parameters. Our results suggest that there is no considerable drop in topological interactions for chains in the vicinity of a single flat surface. We infer from the slip-spring model that the experimental plateau modulus of a confined polymer melt may be different to a corresponding unconfined system even if there is no drop in topological interactions for the confined case.
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Affiliation(s)
- Jack Kirk
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, United Kingdom
| | - Zuowei Wang
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, United Kingdom
| | - Patrick Ilg
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, United Kingdom
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Kirk J, Kröger M, Ilg P. Surface Disentanglement and Slip in a Polymer Melt: A Molecular Dynamics Study. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01865] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jack Kirk
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, U.K
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Patrick Ilg
- School of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, U.K
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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]
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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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Yamamoto T, Tezuka Y. Cyclic polymers revealing topology effects upon self-assemblies, dynamics and responses. SOFT MATTER 2015; 11:7458-7468. [PMID: 26264187 DOI: 10.1039/c5sm01557j] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A variety of single- and multicyclic polymers having programmed chemical structures with guaranteed purity have now become obtainable owing to a number of synthetic breakthroughs achieved in recent years. Accordingly, a broadening range of studies has been undertaken to gain updated insights on fundamental polymer properties of cyclic polymers in either solution or bulk, in either static or dynamic states, and in self-assemblies, leading to unusual properties and functions of polymer materials based on their cyclic topologies. In this article, we review recent studies aiming to achieve distinctive properties and functions by cyclic polymers unattainable by their linear or branched counterparts. We focus, in particular, on selected examples of unprecedented topology effects of cyclic polymers upon self-assemblies, dynamics and responses, to highlight current progress in Topological Polymer Chemistry.
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Affiliation(s)
- Takuya Yamamoto
- Department of Organic and Polymeric Materials, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8552, Japan.
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Wada H, Kitazawa Y, Kuroki S, Tezuka Y, Yamamoto T. NMR Relaxometry for the Thermal Stability and Phase Transition Mechanism of Flower-like Micelles from Linear and Cyclic Amphiphilic Block Copolymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:8739-8744. [PMID: 26230670 DOI: 10.1021/acs.langmuir.5b01902] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Linear and cyclic amphiphilic block copolymers consisting of poly(ethylene oxide) (PEO) as the hydrophilic segment and poly(methyl acrylate) or poly(ethyl acrylate) as the hydrophobic segments were synthesized and self-assembled to form flower-like micelles. The micelles from linear (methyl acrylate)12(ethylene oxide)73(methyl acrylate)12 (Mn = 1000-3200-1000, l-MOM) showed a cloud point (Tc) at 46 °C by the transmittance of the micellar solution, whereas that of cyclic (methyl acrylate)30(ethylene oxide)79 (Mn = 2600-3500, c-MO) increased to 72 °C, as previously reported. DLS showed comparable diameters (l-MOM, 14 nm; c-MO, 12 nm) and Tc values (l-MOM, 48 °C; c-MO, 75 °C). For the investigation of the difference in Tc and the phase transition mechanism based on the polymer topology, NMR relaxometry was performed to determine the spin-lattice (T1) and spin-spin (T2) relaxation times. A decrease in T2 of the PEO segment in both l-MOM and c-MO was observed above Tc, suggesting that slow large-scale motions, such as the detachment of a chain end from the core, bridging, and interpenetration of the micelles, were inhibited. T1 of the PEO segment in l-MOM continuously increased in the experimental temperature range, indicating that the segment is hydrated even above its Tc. On the other hand, that of c-MO reached a ceiling above its Tc, likely due to the prevention of the rotation of the PEO main chain bonds caused by dehydration. Similar results were obtained for linear (ethyl acrylate)8(ethylene oxide)79(ethyl acrylate)8 (Mn = 800-3500-800, l-EOE) and its cyclic (ethyl acrylate)15(ethylene oxide)78 (Mn = 1500-3400, c-EO).
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Affiliation(s)
- Haruna Wada
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Yu Kitazawa
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Shigeki Kuroki
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Yasuyuki Tezuka
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Takuya Yamamoto
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
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Affiliation(s)
- Jing Cao
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jian Qin
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Scott T. Milner
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Affiliation(s)
- Jian Qin
- Institute
for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Scott T. Milner
- Department
of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Affiliation(s)
- Daniel J. Read
- School of Mathematics, University of Leeds; Leeds LS2 9JT United Kingdom
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