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Effects of chain stiffness and shear flow on nanoparticle dispersion and distribution in ring polymer melts

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2020年第3期21卷 229-239页

作者： Dan WANG Feng-qing LI Xiang-hong WANG Shi-ben LI Lin-li HE Department of Physics Wenzhou UniversityWenzhou 320035China

The dispersion behavior and spatial distribution of nanoparticles(NPs)in ring polymer melts are explored by using molecular dynamics(MD)*** polymer-NP interactions increase,three general categories of polymer-mediated NP organization are observed,namely,contact aggregation,bridging,and steric dispersion,consistent with the results of equivalent linear ones in previous *** the case of direct contact aggregation among NPs,the explicit aggregation-dispersion transition of NPs in ring polymer melts can be induced by increasing the chain stiffness or applying a steady shear *** further indicate that NPs can achieve an optimal dispersed state with the appropriate chain stiffness and shear ***,shear flow cannot only improve the dispersion of NPs in ring polymer melts but also control the spatial distribution of NPs into a well-ordered *** improvement becomes more evident under stronger polymer-NP *** observed induced-dispersion or ordered distribution of NPs may provide efficient access to the design and manufacture of high-performance polymer nanocomposites(PNCs).

关键词： ring polymer Nanocomposites Chain stiffness Shear flow Molecular dynamics(MD)

Size and Dynamics of ring polymers under Different Topological Constraints

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Chinese Journal of polymer Science 2023年第4期41卷 516-524,I0006页

作者： Jiang-Yang Mo Zhen-Hua Wang Yu-Yuan Lu Li-Jia An State Key Laboratory of polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China University of Science and Technology of China Hefei230026China

The impact of ring polymer length N and the influence of interchain and intrachain interactions on the size and dynamic behaviors of ring polymers,including the structural relaxation time τ_(R) and self-diffusion coefficient D,remain poorly understood at present due to a lack of systematic studies with relatively large N *** work addressed this issue by applying dynamic Monte Carlo simulations with independently tuned interchain and intrachain interactions to investigate the size and dynamics of the ring melts with chain lengths over a wide range of 0.2N_(e)≤N≤80N_(e)(N_(e) is the entanglement length of corresponding linear chains)under different topological constraints,including all-crossing and intercrossing *** found that it was inappropriate to treat the unknotting constraint free energy of the ring chains in the melts as the free energy contributed by the excluded volume interactions of polymers in a good *** exponents of 2.5 and 1.5 reflecting the Ndependence of τ_(R) were obtained for long ring chains in non-crossing and intra-crossing systems,respectively,suggesting that the ring chains behaved as individual clusters and exhibited Zimm-like dynamics in intra-crossing systems.A single scaling exponent of-2 reflecting the Ndependence of D was obtained for ring chains in non-crossing and intra-crossing systems,indicating that the intrachain constraints affected only the value of D,and had little influence on the scaling relationship between D and ***,the extended Stokes-Einstein relation broke down for the ring chains in the non-crossing and intra-crossing systems because the structural relaxation and translational diffusion were decoupled for the short ring systems,while both the translational diffusion and rotational relaxations,as well as diffusion at short and long time scales,were decoupled for long ring systems.

关键词： ring polymer Topological constraint Extended Stokes-Einstein relation Monte Carlo simulation

Static and dynamic properties of polymer brush with topological ring structures: Molecular dynamic simulation

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Chinese Physics B 2016年第10期25卷 252-258页

作者：万吴兵吕红红候格吴晨旭 Institute of Softmatter and Biometrics Xiamen University Collaborative Innovation Center of Chemistry for Energy Materials Xiamen University

By defining a topological constraint value（rn）,the static and dynamic properties of a polymer brush composed of moderate or short chains with different topological ring structures are studied using molecular dynamics simulation,and a comparison with those of linear polymer brush is also *** the center-of-mass height of the ring polymer brush scaled by chain length h;,there is no significant difference of exponent from that of a linear brush in the small topological constraint ***,as the topological constraint becomes stronger,one obtains a smaller *** is found that there exists a master scaling power law of the total stretching energy scaled by chain length N for moderate chain length regime,F;p;,for ring polymer brushes,but with a larger exponent v than 5/6,indicating an influence of topological constraint to the dynamic properties of the system.A topological invariant of free energy scaled by（c）;is found.

关键词： ring polymer topological invariant scaling