Dynamics of adsorbed polymers on attractive homogeneous surfaces

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.