Eur. Phys. J. E (2012) 35: 88
https://doi.org/10.1140/epje/i2012-12088-7

Regular Article

How flow changes polymer depletion in a slit

¹ Graduate School of Engineering, Kyoto University Katsura Campus, 615-8510, Nishikyo-ku, Kyoto, Japan
² DSM ChemTech, ACES, P.O. Box 18, 6160 MD, Geleen, The Netherlands
³ Van ’t Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
⁴ Department of Mechanical Engineering, University of Connecticut, Massachusetts, 06269, CT, USA

^* e-mail: taniguch@cheme.kyoto-u.ac.jp

Received: 7 February 2012
Revised: 12 June 2012
Accepted: 9 August 2012
Published online: 20 September 2012

Abstract

A theoretical model is developed for predicting dynamic polymer depletion under the influence of fluid flow. The results are established by combining the two-fluid model and the self-consistent field theory. We consider a uniform fluid flow across a slit containing a solution with polymer chains. The two parallel and infinitely long walls are permeable to solvent only and the polymers do not adsorb to these walls. For a weak flow and a narrow slit, an analytic expression is derived to describe the steady-state polymer concentration profiles in a -solvent. In both - and good-solvents, we compute the time evolution of the concentration profiles for various flow rates characterized by the Peclet number. The model reveals the interplay of depletion, solvent condition, slit width, and the relative strength of the fluid flow.