CONTRACTION KINETICS OF STRETCHED POLYMERS VIA LOCAL CONFORMATIONAL-CHANGES

We use the beginning coefficients in exact time power series to study the kinetics of the conformation-to-random coil contraction of a model polymer system. We treat a two-dimensional (2-d) lattice polymer where each unit can exist in the cis or trans state, the stretched conformation corresponding to the all-trans state. We am only local conformational changes that do not perturb the chain beyond a small finite range. The mechanism of contraction then becomes the diffusion of cis states into the chain from the ends. Because of the diffusion mechanism we expect power-law behavior of the form t1/2 (this form is supported by exactly soluble models). We give exact series for short chains and the asymptotic series for very long chains. We find that the t1/2 behavior is truly asymptotic and does not dominate the early behavior as determined by the series.