Threading Behavior and Dynamics of Ring-Linear Polymer Blends under Poiseuille Flow

We investigate the ring-linear polymer blends under Poiseuille flow across a range of flow intensities. As rings are flexible (Kbr = 0), the threading probability gradually increases with an increase in flow field strength. However, as rings are semiflexible (Kbr > 0), the threading probability significantly decreases and then significantly increases as the flow field strength increases. Additionally, for different ring rigidity parameters, the critical flow field strength corresponding to the rapid increase in the threading probability is almost the same. When the flow field strength exceeds this critical value, ring-linear polymer blends will aggregate into a cluster due to the combination of entanglement between polymers and the large differences in the velocities of the polymers. The cluster moves along the direction of the flow field and can be bisected by the flow channel's centerplane into two parts, and each part performs the tank-treading motion in opposite directions: one moving counterclockwise and the other moving clockwise. The dynamic movement of the cluster significantly promotes an increase in threading probability. Furthermore, the nonlinear relationship between the characteristic time of tank-treading motion and flow field strength suggests that the structure of the cluster exhibits similar dynamic and structural behaviors over a certain range of flow field strengths. The results could enhance our understanding of the intricate threading properties observed in ring-linear polymer blends upon exposure to external force fields.