Monte Carlo studies on the long time dynamic properties of dense cubic lattice multichain systems. II. Probe polymer in a matrix of different degrees of polymerization

摘要

The dynamics of a probe chain consisting ofnP=100 segments in a matrix of chains of length ofnM=50 up tonM=800 at a total volume fraction of polymer fgr;=0.5 have been simulated by means of cubic lattice Monte Carlo dynamics. The diffusion coefficient of the probe chain over the range ofnMunder consideration decreases by about 30percnt;, a behavior rather similar to that seen in real melts of very long chains. Furthermore, the analysis of the probe chain motion shows that the mechanism of motion is not reptationhyphen;like and that the cage effect of the matrix is negligible. That is, the local fluctuations of the topological constraints imposed by the long matrix chains (even fornM=800) are sufficiently large to provide for essentially isotropic, but somewhat slowed down, motion of the probe,nP=100, chains relative to the homopolymer melt. The results of these MC experiments are discussed in the context of theoretical predictions and experimental findings for related systems.