Electronic friction and liquid-flow-induced voltage in nanotubes

TL;DR

This paper explains the experimentally observed logarithmic increase in voltage in nanotubes flowing with ion-containing liquids by modeling a stick-slip monolayer of liquid molecules and ion drift causing electronic friction.

Contribution

It introduces a novel model linking liquid flow, monolayer stick-slip dynamics, and ion drift to explain flow-induced voltage in nanotubes.

Findings

Logarithmic voltage growth explained by stick-slip dynamics.

Estimated current and resistance match experimental observations.

Model provides a microscopic mechanism for flow-induced voltages.

Abstract

A recent exciting experiment by Ghosh et al. reported that the flow of an ion-containing liquid such as water through bundles of single-walled carbon nanotubes induces a voltage in the nanotubes that grows logarithmically with the flow velocity v0. We propose an explanation for this observation. Assuming that the liquid molecules nearest the nanotube form a 2D solid-like monolayer pinned through the adsorbed ions to the nanotubes, the monolayer sliding will occur by elastic loading followed by local yield (stick-slip). The drifting adsorbed ions produce a voltage in the nanotube through electronic friction against free electrons inside the nanotube. Thermally excited jumps over force-biased barriers, well-known in stick-slip, can explain the logarithmic voltage growth with flow velocity. We estimate the short circuit current and the internal resistance of the nanotube voltage generator.