Direct observation of cyclic polymer dynamics in shear flow reveals non-equilibrium behavior for flow-based applications

Single ring polymer visualization of DNA-based ring polymers in the flow-gradient plane of shear flow. Trajectories of the ring DNA fractional stretch and orientation angle as a function of applied shear strain reveals microscopic dynamical behavior of single ring polymers in flow.

Scientific Achievement

Single ring polymers were directly visualized in the flow-gradient plane of shear flow to understand their dynamic behavior such as tumbling and stretching in flow, as well as the distribution of polymer conformations far-from-equilibrium.

Significance and Impact

This work provides the first experimental images of ring polymer conformations in shear flow, which is ubiquitous and occurs anytime fluid flows past a stationary solid boundary. This work provides a new understanding of effect of the ring architecture on flow dynamics on circular macromolecules. Ring polymers will be advantageous in reducing solution viscosity compared to linear counterparts in flow, which will greatly aid in the redox flow battery applications.

Research Details

  • We observe similar average conformational variables for linear and ring topologies (fractional stretch, orientation angle, and gradient thickness), yet unexpectedly observe qualitatively different distributions in the chain stretching. The differences are attributed to less conformational degrees of freedom for the ring topology.
  • Single molecule experimental data are corroborated with Brownian dynamics (BD) simulations.

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DOI: 10.1021/acs.macromol.0c01362

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