Brownian dynamics of chain polymers

Abstract

The effect of constrained bond lengths and angles on the Brownian dynamics of wormlike polymer chains is calculated analytically and compared with dynamical simulations. An analytical correspondence between constraints and internal friction is developed and illustrated. The approximate numerical evaluation of the constraint matrix and its correlations, characteristic of previous work, is replaced by an equilibrium simulation. Good agreement is found between the constraint formalism and dynamical simulations. With fluctuating hydrodynamic interaction included, the constraints generate a coupling between local motions and translational diffusion which causes a small decrease in the translational diffusion constant. The effects are similar to those found in a previous phenomenological study of the effects of internal friction on translational diffusion and do not vanish with increasing chain length.