Coarse-grained molecular dynamics simulation of activated penetrant transport in glassy polymers,Soft Matter

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Coarse-grained molecular dynamics simulation of activated penetrant transport in glassy polymers
Soft Matter ( IF 2.9 ) Pub Date : 2017-11-27 00:00:00 , DOI: 10.1039/c7sm01941f
Kai Zhang _{1,

2,

3,

4} , Dong Meng _{4,

5,

6,

7} , Florian Müller-Plathe _{8,

9,

10,

11} , Sanat K. Kumar _{1,

2,

3,

4}

Affiliation

Membrane separations of gas mixtures strive to maximize the permeability of a desired species while keeping out undesired ones. Permeability vs. selectivity data from many polymer membranes for a given gas pair with diameters d_A and d_B are typically collected in a “Robeson plot”', and are bound from above by a line with a slope λ = (d_B/d_A)² − 1. A microscopic understanding of this relationship, especially λ, is still missing. We perform molecular dynamics simulations of penetrant diffusion using three different coarse-grained polymer models over a wide range of penetrant sizes, temperatures, and monomer densities. The empirically relevant λ = (d_B/d_A)² − 1 is only found for polymers that are either supercooled liquids with caged segmental dynamics or glasses and when the penetrant size is approximately half the Kuhn length of the chains, for which the penetrant diffusion is an activated process.

中文翻译：

玻璃态聚合物中活化渗透剂传输的粗粒分子动力学模拟

混合气体的膜分离力求最大程度地增加所需物质的渗透性，同时将不需要的物质排除在外。给定直径为d _A和d _B的气体对的许多聚合物膜的渗透率与选择性的数据通常收集在“ Robeson图”中，并从上方用斜率λ =（d _B / d的线）约束。_A）² − 1.对这种关系的微观理解，尤其是λ，仍然不见了。我们在三种渗透剂尺寸，温度和单体密度范围内，使用三种不同的粗粒聚合物模型对渗透剂扩散进行分子动力学模拟。凭经验相关λ =（d_乙/ d_甲）² - 1仅找到，它们或者过冷液体与笼节段性动力学或眼镜，并且当所述渗透剂大小大约是链的库恩长度的一半，聚合物的量，渗透剂扩散是一个激活的过程。

更新日期：2017-11-27

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