Nonlinear Microrheology Reveals Entanglement-Driven Molecular-Level Viscoelasticity of Concentrated DNA

Cole D. Chapman and Rae M. Robertson-Anderson
Phys. Rev. Lett. 113, 098303 – Published 28 August 2014
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Abstract

We optically drive a trapped microscale probe through entangled DNA at rates up to 100× the disentanglement rate (Wi100), then remove the trap and track subsequent probe recoil motion. We identify a unique crossover to the nonlinear regime at Wi20. Recoil dynamics display rate-dependent dilation and complex power-law healing of the reptation tube. The force response during strain exhibits key nonlinear features such as shear thinning and yielding with power-law rate dependence. Our results, distinctly nonclassical and in accord with recent theoretical predictions, reveal molecular dynamics governed by individual stress-dependent entanglements rather than chain stretching.

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  • Received 29 April 2014

DOI:https://doi.org/10.1103/PhysRevLett.113.098303

© 2014 American Physical Society

Authors & Affiliations

Cole D. Chapman1 and Rae M. Robertson-Anderson2,*

  • 1Department of Physics, University of San Diego, San Diego, California 92110, USA
  • 2Department of Physics, University of California San Diego, La Jolla, California 92093, USA

  • *randerson@sandiego.edu

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Issue

Vol. 113, Iss. 9 — 29 August 2014

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