A random walk chain reptating in a network of obstacles: Monte Carlo study of diffusion and decay of correlations and a comparison with the Rouse and reptation models

摘要

The integrated decay times for correlations of the endhyphen;tohyphen;end vector of random walk chains of lengthNare well known to be proportional toN2andN3for the Rouse and the reptation models, respectively. For subchains of lengthnsituated in the center and at the end of a chain, respectively, these times are aboutnNandn2in the Rouse model andnN2andn2Nin the reptation model ifnLt;Nholds. For a random walk chain in a network of obstacles which moves along its contour by defect diffusion with Monte Carlo simulations, the autocorrelation time for the endhyphen;tohyphen;end vector and the disentanglement time for the primitive path are found to vary as aboutN3.5andN3.7, respectively, for chain lengths varying from 15 to 63. The curvilinear diffusion coefficient varies as aboutNminus;1.2and the centerhyphen;ofhyphen;mass diffusion coefficient varies as aboutNminus;2.4. The integrated autocorrelation times of small subchains vary withn/Nalso faster than predicted by the reptation model.