Eur. Phys. J. Special Topics 223, 3095–3111 (2014)
https://doi.org/10.1140/epjst/e2014-02321-9

Regular Article

Giant enhancement of hydrodynamically enforced entropic trapping in thin channels

¹ Department of Physics, Hardenbergstraße 36, EW 7-1, Technische Universität Berlin, 10623 Berlin, Germany
² Department of Physics, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany
³ Department of Physics, Universität Augsburg, Universitätsstr. 1, 86135 Augsburg, Germany
⁴ Nanosystems Initiative Munich, Schellingstr. 4, 80799 München, Germany

^a e-mail: steffen.martens@tu-berlin.de

Received: 17 October 2014
Revised: 5 November 2014
Published online: 15 December 2014

Abstract

Using our generalized Fick-Jacobs approach [1, 2] and extensive Brownian dynamics simulations, we study particle transport through three-dimensional periodic channels of different height. Directed motion is caused by the interplay of constant bias acting along the channel axis and a pressure-driven flow. The tremendous change of the flow profile shape in channel direction with the channel height is reflected in a crucial dependence of the mean particle velocity and the effective diffusion coefficient on the channel height. In particular, we observe a giant suppression of the effective diffusivity in thin channels; four orders of magnitude compared to the bulk value.