SOLVENT DYNAMICS IN SWOLLEN POLYMERS

We report molecular dynamics simulations of benzene-polystyrene system s (0-84.2 wt.%). The composition dependence of calculated solvent diff usion coefficients shows good agreement with experiment and it also fo llows well the predictions by lattice models. The mobility of solvent molecules in the first solvation shell of the polymer is the same as t hat in the bulk. The reorientation of benzene molecules in the gel is non-exponential and anisotropic, the reorientation of the ring normal being slower than the in-plane reorientation. This anisotropy increase s from 10(0) for neat benzene to 10(3) at the highest polymer concentr ation.