| 초록 |
The tracer diffusion in polymeric materials has been an issue of great importance because the tracer diffusion has played a critical role in improving the performance of fuel cells and separation membranes. Recently, it was found that as one changed the stiffness of polymers, the tracer diffusion was significantly decreased. (J. Phys. Chem. B 113, 2247 (2009)) It is, however, still unclear how the chain stiffness would affect the tracer diffusion and pore space, a dominant factor that influences the tracer diffusion. Therefore, we investigate the effect of the chain stiffness on the diffusion of tracer molecules using molecular simulations. We show that as polymers become stiffer, the tracer diffusion is decreased significantly but the pore percolation threshold concentrations do not vary much. We suggest that the change in the tracer diffusion should be attributed mainly not to a change in pore space but to the segmental dynamics of polymers that slows down. |
