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Exact theory of kinkable elastic polymers

Wiggins, Paul A. and Phillips, Rob and Nelson, Philip C. (2005) Exact theory of kinkable elastic polymers. Physical Review E, 71 (2). Art. No. 021909. ISSN 1063-651X.

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The importance of nonlinearities in material constitutive relations has long been appreciated in the continuum mechanics of macroscopic rods. Although the moment (torque) response to bending is almost universally linear for small deflection angles, many rod systems exhibit a high-curvature softening. The signature behavior of these rod systems is a kinking transition in which the bending is localized. Recent DNA cyclization experiments by Cloutier and Widom have offered evidence that the linear-elastic bending theory fails to describe the high-curvature mechanics of DNA. Motivated by this recent experimental work, we develop a simple and exact theory of the statistical mechanics of linear-elastic polymer chains that can undergo a kinking transition. We characterize the kinking behavior with a single parameter and show that the resulting theory reproduces both the low-curvature linear-elastic behavior which is already well described by the wormlike chain model, as well as the high-curvature softening observed in recent cyclization experiments.

Item Type:Article
Additional Information:©2005 The American Physical Society. Received 31 August 2004; published 23 February 2005. We thank J. Widom and T. Cloutier for sharing their data and insights on DNA bending before they were generally available. P.A.W. thanks A. Spakowitz for insightful conversations and his results before they were generally available, and T.-M. Yan for his careful instruction in the mysteries of quantum mechanics long ago. We also thank M. Inamdar, W. Klug, J. Maddoxs, J. M. Schurr, and Z.-G. Wang for helpful discussions and correspondence and Yongli Zhang for comments on the draft manuscript. We acknowledge grant support from the NSF (P.A.W.); the Human Frontier Science Foundation and NSF Grant No. DMR-0404674 (P.N.); the Keck Foundation, NSF Grant No. CMS-0301657, the NSF funded Center for Integrative Multiscale Modeling and Simulatio, as well as the NIH Director’s Pioneer Award (R.P. and P.A.W.).
Subject Keywords:polymers; DNA; molecular biophysics; statistical mechanics; torque; continuum mechanics; bending
Record Number:CaltechAUTHORS:WIGpre05
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3730
Deposited By: Tony Diaz
Deposited On:30 Jun 2006
Last Modified:26 Dec 2012 08:55

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