GAS SORPTION AND TRANSPORT IN POLYISOBUTYLENE - EQUILIBRIUM AND NONEQUILIBRIUM MOLECULAR-DYNAMICS SIMULATIONS
GAS SORPTION AND TRANSPORT IN POLYISOBUTYLENE - EQUILIBRIUM AND NONEQUILIBRIUM MOLECULAR-DYNAMICS SIMULATIONS
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DOI：
10.1063/1.464369
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发表时间：
1993-06-15
影响因子：
4.4
通讯作者：
VANGUNSTEREN, WF
中科院分区：
文献类型：
--
作者：
MULLERPLATHE, F;ROGERS, SC;VANGUNSTEREN, WF
分子动力学计算报告的吸附和扩散的小气体分子（He，H-2，和O2）在无定形聚异丁烯。一个全原子力场（与明确的氢原子）被使用。除了通过均方位移从平衡计算中获得扩散系数的标准方法外，我们还使用了一种非平衡技术，该技术选择性地对气体分子施加虚拟的外部场。据我们所知，非平衡分子动力学是，第一次，应用于聚合物中的气体扩散问题。两种技术的结果进行了比较。研究了ps在聚合物中扩散的跳跃事件的能量分布。我们还讨论了可能存在的异常（非爱因斯坦）行为的气体分子扩散通过无定形聚合物。用粒子插入法计算了气体在聚异丁烯中的溶解度
Molecular dynamics calculations are reported on the sorption and diffusion of small gas molecules (He, H-2, and O2) in amorphous polyisobutylene. An all-atom force field (with explicit hydrogen atoms) was used. In addition to the standard method of obtaining the diffusion coefficient from an equilibrium calculation via the mean-square displacement we used a nonequilibrium technique that applies a fictitious external field selectively to the gas molecules. To our knowledge, nonequilibrium MD is, for the first time, applied to the problem of gas diffusion in polymers. Results of both techniques are compared. Energy profiles of the jump events underlying ps diffusion through polymers are studied. We also discuss the possible presence of anomalous (non-Einstein) behavior of gas molecules diffusing through an amorphous polymer. Gas solubilities in polyisobutylene are calculated by particle-insertion