Tumbling and tank-treading dynamics of individual ring polymers in shear flow

Abstract

The dynamics of individual ring polymers in a shear flow is studied by a hybrid mesoscale simulation approach. New insight into the dynamics of ring polymers is provided: ring polymers exhibit both tumbling and tank-treading motions. A novel angle autocorrelation function is proposed to analyze the tank-treading motion that usually coexists with tumbling and may be applied to other highly deformable soft objects such as vesicles. The shear dependence of the average gyration tensor, the orientation angle, the tumbling and the tank-treading frequencies is determined quantitatively. The simulations also reveal that the existence of the tank-treading motion apparently increases the intrinsic viscosity of ring polymers under shear flow.

Effects of excluded volume and hydrodynamic interaction on the deformation, orientation and motion of ring polymers in shear flow

“…27 Similar to the linear polymers, the curves decay to zero sharply and no secondary peak is found in the absence of EV for ring polymers [see Fig. 27 Similar to the linear polymers, the curves decay to zero sharply and no secondary peak is found in the absence of EV for ring polymers [see Fig.…”

“…In order to deeply understand the effects of EV and HI on the stretching behaviors of ring polymers, the probability distribution functions (PDFs) of the average molecular extension P(G xx ) are presented in Fig. [27][28][29][30] Without self-avoidance, individual ring polymers tend to form a two-strand line rather than an ellipse shape in the flow-gradient plane. For small Wi (Wi o 1), the distribution is practically Gaussian.…”

“…Therefore, m G is independent of Wi. [27][28][29][30] Moreover, a universal curve is obtained for orientation with and without HI, implying that the orientation behaviors scaled with Wi have no qualitative difference in the presence and absence of HI. With increasing Wi, ring polymers orient with the flow direction and the conformations are strongly deformed.…”

“…27 In TB motion, ring chains continuously undergo stretching, aligning, flipping, and collapsing with large deformation, while, in TT motion, the chain adopts an elliptical shape in the flow-gradient plane due to the strong EV interactions between the two strands of flexible ring polymers. 27 In TB motion, ring chains continuously undergo stretching, aligning, flipping, and collapsing with large deformation, while, in TT motion, the chain adopts an elliptical shape in the flow-gradient plane due to the strong EV interactions between the two strands of flexible ring polymers.…”

“…23,24 For ring polymers, the close topology results in higher monomer density, and EV interaction shows a stronger impact. [27][28][29][30] How the EV interaction affects these two motions and the conformation change for ring polymers in shear flow has not been reported yet. [27][28][29][30] How the EV interaction affects these two motions and the conformation change for ring polymers in shear flow has not been reported yet.…”