Implications of Interactions between Steric Effects and Electrical Double Layer Overlapping Phenomena on Electro-Chemical Transport in Narrow Fluidic Confinements

Abstract

In this paper, we study the non-trivial interactions between the ionic Steric effects and Electric Double Layer (EDL) overlap phenomenon on the resultant electro-chemical transport in narrow fluidic confinements. Through a comprehensive mathematical model, we demonstrate that more prominent Steric effects may result in greater magnitudes of the channel centerline potential. However, since the magnitude of the zeta potential also gets perpetually enhanced with Steric interactions, this phenomenon cannot by be considered by itself as a trivial interpreter of an augmentation in the extent of the effective EDL overlap. Further investigations in this regard, however, do reveal an intricate coupling between EDL overlap phenomenon and finite ionic size effects, so as to result in an effective enhancement in the extent of EDL overlap, far beyond what is predicted by classical electrochemical considerations. Insights are also provided on the possible implications of the intricate interactions of the underlying physico-chemical mechanisms on the design of future- generation nanofluidic devices.