Static and Dynamic Properties of Adsorbed Chains at Surfaces: Monte Carlo Simulation of a Bead-Spring Model

The adsorption of flexible polymers from dilute solution in good solvents at attractive walls is studied by Monte Carlo simulation of a coarse-grained off-lattice model, varying chain length N and the strength e of a short-range attractive wall potential. Unlike many previous studies, no chain end (or other monomer) is held fixed near the wall. In qualitative agreement with previous work on different models, we find an adsorption transition at a critical strength of the wall potential, where the chain configuration changes from three-dimensional to quasi-two-dimensional in the limit of very long chains. The dynamics of the chains is studied both above and below this adsorption threshold ec. Time-dependent mean-square displacements of monomers and the chain center of gravity as well as the associated relaxation times are studied in detail. In the adsorbed phase, relaxation times are found to scale as τ ∝ Nzeff with zeff ≈ 2.65 ± 0.1 and the lateral diffusion constant scales as DN ∝ N-yeff with yeff ≈ 1.1. ...