Yong Xin
Department of Mechanical Engineering, State University of New York at Binghamton, Binghamton, NY 13902, USA.
Polymers (Basel). 2016 Dec 9;8(12):426. doi: 10.3390/polym8120426.
Using many-body dissipative particle dynamics (MDPD), polymer solutions with concentrations spanning dilute and semidilute regimes are modeled. The parameterization of MDPD interactions for systems with liquid⁻vapor coexistence is established by mapping to the mean-field Flory⁻Huggins theory. The characterization of static and dynamic properties of polymer chains is focused on the effects of hydrodynamic interactions and entanglements. The coil⁻globule transition of polymer chains in dilute solutions is probed by varying solvent quality and measuring the radius of gyration and end-to-end distance. Both static and dynamic scaling relations for polymer chains in poor, theta, and good solvents are in good agreement with the Zimm theory with hydrodynamic interactions considered. Semidilute solutions with polymer volume fractions up to 0.7 exhibit the screening of excluded volume interactions and subsequent shrinking of polymer coils. Furthermore, entanglements become dominant in the semidilute solutions, which inhibit diffusion and relaxation of chains. Quantitative analysis of topology violation confirms that entanglements are correctly captured in the MDPD simulations.
使用多体耗散粒子动力学（MDPD）对浓度跨越稀溶液和半稀溶液区域的聚合物溶液进行建模。通过映射到平均场弗洛里-哈金斯理论，建立了具有液-气共存系统的MDPD相互作用参数化。聚合物链静态和动态性质的表征重点关注流体动力学相互作用和缠结的影响。通过改变溶剂质量并测量回转半径和端到端距离，研究了稀溶液中聚合物链的线团-球粒转变。在考虑流体动力学相互作用的情况下，贫溶剂、θ溶剂和良溶剂中聚合物链的静态和动态标度关系与齐默尔理论吻合良好。聚合物体积分数高达0.7的半稀溶液表现出排除体积相互作用的屏蔽以及随后聚合物线团的收缩。此外，缠结在半稀溶液中占主导地位，这抑制了链的扩散和弛豫。拓扑违规的定量分析证实，缠结在MDPD模拟中得到了正确捕捉。
