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Polymer extension under flow: A path integral evaluation of the free energy change using the Jarzynski relation

Ghosal, Aishani and Cherayil, Binny J (2016) Polymer extension under flow: A path integral evaluation of the free energy change using the Jarzynski relation. In: JOURNAL OF CHEMICAL PHYSICS, 144 (21).

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Official URL: http://dx.doi.org/10.1063/1.4952765


The Jarzynski relation (and its variants) has provided a route to the experimental evaluation of equilibrium free energy changes based on measurements conducted under arbitrary non-equilibrium conditions. Schroeder and co-workers Soft Matter 10, 2178 (2014) and J. Chem. Phys. 141, 174903 (2014)] have recently exploited this fact to determine the elastic properties of model DNA from simulations and experiments of chain extension under elongational flow, bypassing the need to make these measurements mechanically using sophisticated optical trapping techniques. In this paper, motivated by these observations, we investigate chain elasticity analytically, using the Jarzynski relation and a finitely extensible nonlinear elastic-type Rouse model within a path integral formalism to calculate (essentially exactly) both the flow-induced free energy change between chain conformations of definite average end-to-end distance, as well as the force-extension curve that follows from it. This curve, based on a new analytic expression, matches the trends in the corresponding curve obtained from a model of chain stretching developed by Marko and Siggia Macromolecules 28, 8759 (1995)], which itself is in very satisfactory agreement with the numerical and experimental data from the work of Schroeder et al. Published by AIP Publishing.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the AMER INST PHYSICS, USA
Department/Centre: Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited: 24 Aug 2016 09:24
Last Modified: 24 Aug 2016 09:24
URI: http://eprints.iisc.ac.in/id/eprint/54368

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