Semiflexible chain molecules with nonuniform curvature, 2. . Brownian dynamics simulations of electric dichroism orientation dynamics

The hydrodynamically induced orientation dynamics of charged polymer molecules during electric dichroism has been studied by Brownian dynamics simulations. The effect of a locally changed flexibility or bending angle has been of special interest. The results show that simultaneously changing the bending angles and the corresponding force constants so as to keep the persistence length constant does not produce any large changes in the orientation dynamics or molecular shape although, quantitatively, a larger number of kinks in the chain will give a smaller steady-state orientation. Releasing the constraint of a fixed persistence length when randomly increasing or decreasing the flexibility at different positions in the molecule drastically changes the dynamics, and the corresponding results are discussed and also compared with the orientation obtained when introducing the inhomogeneities in a cooperative manner.