Temporal modulation of a spatially periodic potential for kinetically governed oriented motion

This theoretical paper introduces an experimental protocol derived from the concept of Brownian motors in order to selectively confer an oriented motion to given charged reactants. Instead of maintaining permanently the system in nonequilibrium conditions, we propose a simple experimental trick to restore periodically a transient out-of-equilibrium regime: the reactive medium is alternately submitted to a sawtooth potential and to a potential ramp. The model provides approximate analytical expressions for the operating conditions allowing us to design the extraction from a mixture of any desired reactant characterized by its rate constants. The orders of magnitude suggest a possible implementation in microsystems where the present approach could be used for separation and analysis.