Session W18 - Computer Simulation II.
ORAL session, Thursday morning, March 15
Room 308-308, Washington State Convention Center
Processes on different length scales affect the dynamics of chain molecules. A convenient measure for small-scale effects is the (monomeric) friction coefficient, which is inversely proportional to the mobility of individual chain segments. Local friction in polymers depends on small-scale chain properties such as local architecture and flexibility and on the local environment of the chain segments. In polymer melts, the density is the important environmental variable. In mixtures of polymers, the local concentration will also play a role. In this work, we investigate local friction in dense polymeric fluids with the aid of a small-scale simulation approach. By evaluating exact enumeration results for two short chain sections on a lattice in conjunction with an equation of state, we are able to make predictions about the variation of segmental mobility with local chain architecture, flexibility, and thermodynamic state (temperature, pressure, composition). We apply the approach here to polyolefins and compare our predictions with experimental data.