Surface diffusion and relaxation of partially adsorbed polymers

✍ Scribed by A. L. Ponomarev; T. D. Sewell; C. J. Durning

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 155 KB
• Volume: 38
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(20000501)38:9<1146::aid-polb6>3.0.co;2-l

✦ Synopsis

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 T s , and the segmental friction factor on the surface relative to that in the bulk, s / b . The simulation data indicate Rouse scaling of the surface diffusion coefficient, D ʈ , and in-plane relaxation time, , versus N for all values of T s and s / b studied. A simple application of the Rouse model to a partially adsorbed chain, which ignores fluctuations in adsorbed trains, yields a formula for D ʈ with the correct N-scaling. It can account for the effects of T s when s / b is finite (Շ10), but it fails when s / b diverges, predicting no surface diffusion at all, whereas simulations indicate finite surface mobilities facilitated by a caterpillar-like motion.