中国物理B ›› 2012, Vol. 21 ›› Issue (7): 74208-074208.doi: 10.1088/1674-1056/21/7/074208

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Sorption and permeation of gaseous molecules in amorphous and crystalline PPX C membranes: molecular dynamics and grand canonical Monte Carlo simulation studies

边亮, 舒远杰, 王新峰   

  1. Institute of Chemicals Materials, Chinese Academy of Engineering Physics, Mianyang 621900, China
  • 收稿日期:2011-10-05 修回日期:2012-03-11 出版日期:2012-06-01 发布日期:2012-06-01

Sorption and permeation of gaseous molecules in amorphous and crystalline PPX C membranes: molecular dynamics and grand canonical Monte Carlo simulation studies

Bian Liang(边亮), Shu Yuan-Jie(舒远杰), and Wang Xin-Feng(王新峰)   

  1. Institute of Chemicals Materials, Chinese Academy of Engineering Physics, Mianyang 621900, China
  • Received:2011-10-05 Revised:2012-03-11 Online:2012-06-01 Published:2012-06-01
  • Contact: Shu Yuan-Jie E-mail:syjfree@sina.com

摘要: Amorphous and crystalline poly (chloro-p-xylylene) (PPX C) membranes are constructed by using a novel computational technique, that is, a combined method of NVT+NPT-molecular dynamics (MD) and gradually reducing the size (GRS) methods. The related free volumes are defined as homology clusters. Then the sorption and the permeation of gases in PPX C polymers are studied using grand canonical Monte Carlo (GCMC) and NVT-MD methods. The results show that the crystalline PPX C membranes provide smaller free volumes for absorbing or transferring gases relative to the amorphous PPX C area. The gas sorption in PPX C membranes mainly belongs to the physical one, and H bonds can appear obviously in the amorphous area. By cluster analyzing on the mean square displacement of gases, we find that gases walk along the x axis in the crystalline area and walk randomly in the amorphous area. The calculated permeability coefficients are close to the experimental data.

关键词: cluster analysis, parylene C, grand canonical Monte Carlo method, molecular dynamics

Abstract: Amorphous and crystalline poly (chloro-p-xylylene) (PPX C) membranes are constructed by using a novel computational technique, that is, a combined method of NVT+NPT-molecular dynamics (MD) and gradually reducing the size (GRS) methods. The related free volumes are defined as homology clusters. Then the sorption and the permeation of gases in PPX C polymers are studied using grand canonical Monte Carlo (GCMC) and NVT-MD methods. The results show that the crystalline PPX C membranes provide smaller free volumes for absorbing or transferring gases relative to the amorphous PPX C area. The gas sorption in PPX C membranes mainly belongs to the physical one, and H bonds can appear obviously in the amorphous area. By cluster analyzing on the mean square displacement of gases, we find that gases walk along the x axis in the crystalline area and walk randomly in the amorphous area. The calculated permeability coefficients are close to the experimental data.

Key words: cluster analysis, parylene C, grand canonical Monte Carlo method, molecular dynamics

中图分类号:  (Polymers and organics)

  • 42.70.Jk
21.60.Gx (Cluster models) 68.43.Mn (Adsorption kinetics ?) 82.56.Lz (Diffusion)