Effect of stiffness on tumbling dynamics of short worm-like polymers under mixed flows

This study examined the effects of the stiffness on the tumbling dynamics of short semi-flexible polymers in mixed flows varying from simple shear to pure rotation, as an extension of a previous study on rod-like polymers. A multi bead-rod model with bending potential was adopted and represented the stiffness or persistence length of the polymers. The rotational time and angular distribution of the semi-flexible chains were examined in mixed flows. These results were compared with previous theoretical predictions and numerical simulations of rod-like polymers. Furthermore, the angular distribution of the short semi-flexible polymers was strongly dependent upon the stiffness of the polymers. These results are expected to be helpful in the development of lab-on-a-chip applications, such as the separation of short DNA molecules.