The results of realistic computer simulations of dense polymer melts filled
with solid nanoparticles are compared with results obtained for similar sy
stems near planar solid surfaces and with those of Monte Carlo calculations
performed for single chains in the presence of spherical solid obstacles.
The polymer units at the interface with the filler particles are arranged i
n densely packed and ordered shells analogous to those found near planar so
lid surfaces. The polymer chains, reduced in size compared to the unfilled
melt, are constituted of sequences of surface segments, totally contained i
n the interface shell of a given particle, and of bridge segments, connecti
ng different particles. Each chain visits the interface shell of several fi
ller particles, and each particle is in contact with many different polymer
chains, such that the filler particles behave as highly functional physica
l cross-links.