Dynamics of a polymer in a quenched random medium: A Monte Carlo investigationA. Milchev1, 2, V. G. Rostiashvili1 and T. A. Vilgis1
1 Max Planck Institute for Polymer Research Ackermannweg 10, 55128 Mainz, Germany
2 Institute for Physical Chemistry, Bulgarian Academy of Sciences 1113 Sofia, Bulgaria
received 11 December 2003; accepted in final form 1 September 2004
published online 16 October 2004
We use an off-lattice bead-spring model of a self-avoiding polymer chain immersed in a 3-dimensional quenched random medium to study chain dynamics by means of a Monte Carlo (MC) simulation. The chain center-of-mass mean-squared displacement as a function of time reveals two crossovers which depend both on chain length N and on the degree of Gaussian disorder . The first one from normal to anomalous diffusion regime is found at short time and observed to vanish rapidly as with growing disorder. The second crossover back-to-normal diffusion, , scales as with f being some scaling function. The diffusion coefficient DN depends strongly on disorder and drops dramatically at a critical dispersion of the disorder potential so that for the chain center of mass is practically frozen. These findings agree well with our recent theoretical predictions.
36.20.-r - Macromolecules and polymer molecules.
71.55.Jv - Disordered structures; amorphous and glassy solids.
07.05.Tp - Computer modeling and simulation.
© EDP Sciences 2004