Fluidic rectification due to asymmetric concentration polarization at nano-microfluidic interface

A simple 1D locally electroneutral (LEN) electro-diffusive model explains steady-state fluidic rectification in terms of asymmetry in the diffusion layers flanking a charge-selective element such as a porous membrane or nano-pore. The selectivity in such systems is a function of the diffusion layer asymmetry and applied voltage. Rectification is experimentally demonstrated in a microfluidic system utilizing a charge selective membrane with symmetric nanopores where the asymmetry of the diffusion layers is attributed to the geometric asymmetry in the fluidic portion of the system. Results for devices with different cross-sections on either side of the membrane verify that increasing asymmetry in the geometry, hence diffusion layers, increases the strength of the observed rectification as predicted by the theory.