A semiflexible alternating copolymer chain adsorption on a flat and a fluctuatingsurface

Abstract

A lattice model of a directed self-avoiding walk is used to investigate adsorptionproperties of a semiflexible alternating copolymer chain on an impenetrable flat andfluctuating surface in two (square, hexagonal and rectangular lattice) and threedimensions (cubic lattice). In the cubic lattice case the surface is two-dimensionalimpenetrable flat and in two dimensions the surface is a fluctuating impenetrable line(hexagonal lattice) and also flat impenetrable line (square and rectangular lattice).Walks of the copolymer chains are directed perpendicular to the plane of thesurface and at a suitable value of monomer surface attraction, the copolymerchain gets adsorbed on the surface. To calculate the exact value of the monomersurface attraction, the directed walk model has been solved analytically usingthe generating function method to discuss results when one type of monomer ofthe copolymer chain has attractive, repulsive or no interaction with the surface.Results obtained in the flat surface case show that, for a stiffer copolymer chain,adsorption transition occurs at a smaller value of monomer surface attractionthan a flexible copolymer chain while in the case of a fluctuating surface, theadsorption transition point is independent of bending energy of the copolymerchain. These features are similar to that of a semiflexible homopolymer chainadsorption.