Enrichment of the chain ends in polymer melts at interfaces

Abstract
By Monte Carlo simulation of two lattice models of polymer melts, the enrichment of the chain ends in the vicinity of a wall is obsserved. For the bond fluctuation model with attractive interactions between the ends and wall, ε/kB T=-1 and 0, the enhancement of the density of ends increases with chain lengths, while when the interaction is repulsive, ε/kB T=+1, the ends get depleted. The self-avoiding walk model was simulated with the slithering snake algorithm and behaves similarly. The polymer center of mass density profile, radius of gyration and end-to-end distance components parallel and perpendicular to the wall as functions of center of mass distance z scale with Rg, where Rg is radius of gyration of the polymer chains in the bulk