Dynamics of adsorbed polymers on attractive homogeneous surfaces

Abstract

Dynamic behaviors of polymer chains adsorbed on an attractive, homogeneous surface are studied by using dynamic Monte Carlo simulations. The translational diffusion coefficient D _xy parallel to the surface decreases as the intra-polymer attraction strength E _PP or the polymer-surface attraction strength E _PS increases. The rotational relaxation time τ _R increases with E _PS, but the dependence of τ _R on E _PP is dependent on the adsorption state of the polymer. We find that τ _R decreases with increasing E _PP for a partially adsorbed polymer but it increases with E _PP for a fully adsorbed polymer. Scaling relations D _xy ~  N ^−α and τ _R ~  N ^β are found for long polymers. The scaling exponent α is independent of E _PS for long polymers but increases with E _PP from α = 1.06 at E _PP = 0. While β ≈ 2.7 is also roughly independent of E _PS for the adsorbed polymer at E _PP = 0, but β increases with E _PS at E _PP > 0. Moreover, we find that β always decreases with increasing E _PP. Our results reveal different effects of the attractive surface on the diffusion and rotation of adsorbed polymers.