Eur. Phys. J. Special Topics 223, 3079–3093 (2014)
https://doi.org/10.1140/epjst/e2014-02320-x

Review

Engineering tube shapes to control confined transport

Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain

^a e-mail: dreguera@ub.edu

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

Abstract

Transport of particles in confined structures can be modeled by means of diffusion in a potential of entropic nature. The entropic transport model proposes a drift-diffusion kinetic equation for the evolution of the probability density in which the diffusion coefficient depends on position and the drift term contains an entropic force. The model has been applied to analyze transport in single cavities and through periodic structures of different shape, and to investigate the nature of non-equilibrium fluctuations as well. The transport characteristics depends strongly on the contour of the region through which particles move, which defines the entropic potential. We show that the form of the entropic potential can be properly designed to optimize and govern how molecules diffuse and get drifted in tortuous channels. The shape of a tube or channel can be smartly engineered to control transport for the desired application.