Numerical Modeling of the Bistability of Electrolyte Transport in Conical Nanopores

H. White[1], L. Luo[1]
[1]Department of Chemistry, University of Utah, Salt Lake City, UT, USA

A characteristic feature of nanochannels is that surface properties (e.g., electrical charge) play a more significant role in the transport of fluid and electrolyte. Two oppositely directed flows (electroosmotic flow and pressure-driven flow) determine the flow profile at the nanopore orifice as well as electrolyte distribution. Once there are two electrolyte solutions with different concentrations inside and outside, a conductivity bistability, a sudden transition between two states with different conductivities, is observed. A simulation in COMSOL Multiphysics® semi-quantitatively captures the experimental observations and provides important information about the mechanism of the bistability.