Structure and dynamics of confined polymer melts

Abstract

It is shown that the chain mobility normal to the wall decreases strongly in the vicinity of the wall and it approaches monotonically the bulk value at a distance larger than but comparable to the chain size. This effect is further enhanced by the presence of significant wall attraction. The decrease of the polymer mobility close to the solid surface results from the difficulty of partially flattened chains to move normal to the plane of their preferential alignment as well as from the higher polymer density in the wall vicinity. The mobility parallel to the wall increases slightly close to the solid surfaces. The combined effects of two walls (narrow pores) do not affect significantly the chain mobility unless the wall exerts strong attractive forces on the polymer segments. In that case, the chain mobility normal to the walls is further reduced by the approach of the two surfaces.