The effects of slit-like confinement on flow-induced polymer deformation

Ghosal, Aishani and Cherayil, Binny J (2017) The effects of slit-like confinement on flow-induced polymer deformation. In: JOURNAL OF CHEMICAL PHYSICS, 147 (6).

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Abstract

This paper is broadly concerned with the dynamics of a polymer confined to a rectangular slit of width D and deformed by a planar elongational flow of strength (gamma) over dot. It is interested, more specifically, in the nature of the coil-stretch transition that such polymers undergo when the flow strength (gamma) over dot is varied, and in the degree to which this transition is affected by the presence of restrictive boundaries. These issues are explored within the framework of a finitely extensible Rouse model that includes pre-averaged surface-mediated hydrodynamic interactions. Calculations of the chain's steady-state fractional extension using this model suggest that different modes of relaxation (which are characterized by an integer p) exert different levels of control on the coil-stretch transition. In particular, the location of the transition (as identified from the graph of x versus the Weissenberg number Wi, a dimensionless parameter defined by the product of (gamma) over dot and the time constant tau(p) of a relaxation mode p) is found to vary with the choice of tau(p). In particular, when tau(1) is used in the definition of Wi, the x vs. Wi data for different D lie on a single curve, but when tau(3) is used instead (with tau(3) > tau(1)) the corresponding data lie on distinct curves. These findings are in close qualitative agreement with a number of experimental results on confinement effects on DNA stretching in electric fields. Similar D-dependent trends are seen in our calculated force vs. Wi data, but force vs. x data are essentially D-independent and lie on a single curve. Published by AIP Publishing.

Item Type:	Journal Article
Publication:	JOURNAL OF CHEMICAL PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	16 Sep 2017 06:16
Last Modified:	16 Sep 2017 06:16
URI:	http://eprints.iisc.ac.in/id/eprint/57818

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