Effect of surface coverage on the configurational properties of adsorbed chains

Abstract

Using a Monte Carlo simulation method, the effect of surface coverage on the configurational properties of tetrahedral chains, terminally anchored to an adsorbent plane, has been evaluated assuming a periodic boundary model. Properties considered in the present study include dimensions of the adsorbate chains, thickness of the adsorbed layer, fraction of the segments attached to the adsorbent plane and the density distributions of segments in the layer. The study reveals that at low and medium coverage there is only a small dependence of the properties on surface area per molecule, but in the region of high coverage the effect is dramatic. The approach of the systems with attractive segment/surface energy to high coverage is accompanied by an appreciable coiling of the chains, but with the further increase in coverage the chains expand extremely rapidly in the direction normal to the surface. In the close packing limit, the chains would assume the fully-extended configuration.