Statistics and dynamics of blends of linear and ring polymers.

This work focuses on conformations and dynamics of blends of linear and ring polymers. Rings in a melt of homo-polymer rings are compressed due to topology, if rings are significantly larger than the entanglement length. Dilute rings with degree of polymerization, $N_{r}$, immersed in a melt of linear polymers with degree of polymerization, $N_{l}$ are almost ideal if $N_{l} > N_{r}^{1/2}$ and swell if $N_{l} < N_{r}^{1/2}$. Dynamics of pure ring melts is enhanced as compared to pure linear melts. Thus, minority of linear chains immersed in ring melt experiences enhancement of diffusion and relaxation. On the other hand, minority of long entangled rings immersed in melt of long entangled linear chains gets temporarily trapped. This leads to a clear reduction in diffusion coefficient while keeping relaxation (as determined by half ring relaxation) almost unaffected.