Abstract: | We studied by lattice simulation the surface diffusion and relaxation of isolated, self‐avoiding polymers partially adsorbed onto a flat surface. The key parameters describing the system are the number of segments in the chain, N, the adsorption energy of a segment, expressed as a dimensionless surface temperature Ts, and the segmental friction factor on the surface relative to that in the bulk, ζs/ζb. The simulation data indicate Rouse scaling of the surface diffusion coefficient, D∥, and in‐plane relaxation time, τ, versus N for all values of Ts and ζs/ζb studied. A simple application of the Rouse model to a partially adsorbed chain, which ignores fluctuations in adsorbed trains, yields a formula for D∥ with the correct N‐scaling. It can account for the effects of Ts when ζs/ζb is finite (?10), but it fails when ζs/ζb diverges, predicting no surface diffusion at all, whereas simulations indicate finite surface mobilities facilitated by a caterpillar‐like motion. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1146–1154, 2000 |