Effect of presence of salt on the dynamics of water in uncharged nanochannels

Abstract

Energy conversion and generation mechanisms at nano-scales often include tapping power from pressure-driven flow of water containing dissolved salts in nanofluidic channels. The deviation of such flows from continuum behaviour can often be advantageously utilized to enhance the energy conversion efficiency. Here, by executing molecular dynamics simulations, we pinpoint alterations in effective stick-slip at the solid-liquid interface as a function of variation in the nature of the salt as well as salt solution concentration for different substrate wettabilities, which could possibly act as a control towards modulating energy conversion efficiencies of nanofluidic devices. Our results reveal that the presence of salt has distinctive effects in wettable and non-wettable channels. Finally, we address the observed slip length deviation quantitatively based on hydration energy of the individual ionic species.