Tuning the Preferential Direction of Ion Flow in Asymmetric Nanofluidic Mediums

Current rectification and electrokinetic flow properties in an asymmetric nanochannel a thermoplastic polyurethane membrane were investigated experimentally numerically. The with tip diameter of about 300 nm showed current rectification, which is evident only nanochannels much smaller radii (<100 nm), due to the surface material. To elucidate mechanism mathematical model consisting Nernst - Planck equations for ionic mass transport, Poisson’s equation electrostatics, Navier – Stokes field has been developed. It was verified that obtained numerical results qualitative agreement experimental obtained. concluded charge channel material, significantly thick electric double layer formed on inner contact electrolyte, this gating because overlapping layers near nanochannel. found applied concentration gradient as effective low potentials thus can reverse preferential direction ion flow.