Monte Carlo studies of the melt–vacuum interface of a lattice polymer

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Abstract
A film of polymer on a five way cubic lattice is adsorbed on a smooth solid surface with one face exposed to the vacuum. The properties of the film are examined using a Monte Carlo algorithm which employs a combination of reptative and pseudokinetic ‘‘movements.’’ The film which forms exhibits three distinct layers, with two interfacial regions sandwiching a central region. The polymer in that central region is shown to have characteristics of the bulk melt. The density of beads, the density of ends, and the density of the centers of mass of individual chains are all calculated for a number of temperatures. The densities of beads and ends decrease monotonically across the melt–vacuum interface, but the center‐of‐mass density shows pronounced peak structure near both interfaces. Analysis of the conformations of the polymer in the neighborhood of the interfaces shows the chains to be asymmetrically flattened at both surfaces. The structural features near the melt–vacuum interface are not found to scale in an obvious way with the molecular weight.