Formalizing Poisson-Boltzmann Theory for Field-Tunable Nanofluidic Devices

Abstract

Nanofluidic devices prompts unconventional ion transports appealing to energy and information technologies, thanks to the susceptibility of confined electric double layers (EDL) to various external physical fields. Although experimental studies advance rapidly, the rationalization of field-tunable nanofluidic transports has not reached a formalized and unified level. Here we formally reformulate the Poisson-Boltzmann theory and reveal distinct EDL regimes on the parameter space. Based on the regime classification, we establish a formal framework for the tunable nanofluidic transport, which reproduces the observed conductivity-concentration scaling behaviors, rationalizes the ionic transistors with reconfigurable polarities, and predicts two fundamental thermodynamic limits for electrostatic modulation (60 mV/dec and 120 mV/dec). Being accurate, generalizable and extensible, this framework can account for a wide range of ion transports in confined spaces.