Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (10): 2523-2530.doi: 10.3866/PKU.WHXB201606292

• ARTICLE • Previous Articles     Next Articles

Molecular Dynamics Simulation of Gas Transport in Amorphous Polyisoprene

Xiang LU1,*(),Xun CHEN1,Ya-Shun WANG1,Yuan-Yuan TAN1,Zi-Yuan GAOMU2   

  1. 1 Laboratory of Science and Technology on Integrated Logistics Support, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha 410073, P. R. China
    2 Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G0X6, Canada
  • Received:2016-04-28 Published:2016-09-30
  • Contact: Xiang LU
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(51375487,51205402)


Molecular dynamics (MD) simulations were performed to study the transport properties of gases (oxygen, nitrogen, and methane) in amorphous cis-1,4-polyisoprene over a wide range of temperatures. The COMPASS force field was used as the molecular mechanics force field in the simulations. Experimental values of density and glass transition temperature were successfully reproduced using the atomistic potentials determined by COMPASS. Diffusion coefficients were determined from long NVT simulation times (up to 3 or 1.5 ns) in the temperature range of 278-378 K. The diffusion coefficients calculated fromthe Einstein relationship agree well with available experimental data. Further studies on the temperature dependence of diffusion coefficients indicate that curvature is observed in the Arrhenius plot of diffusivity versus inverse temperature for methane, but the plots are linear over the investigated temperature range for oxygen and nitrogen. These simulation results are useful to understand the temperature dependence of diffusion coefficients, and provide a basis for the determination of diffusion coefficients at high temperatures and the modeling of thermo-oxidative degradation of polyisoprene.

Key words: Gas, Diffusion coefficient, Polyisoprene, Molecular dynamics, Molecular simulation