Repulsive thermal van der Waals interaction in multi-species asymmetric electrolytes driven by external electric fields

TL;DR

This paper explores how external electric fields can induce long-range repulsive thermal van der Waals interactions in multi-species asymmetric electrolytes, extending previous findings from symmetric binary electrolytes.

Contribution

It generalizes the understanding of electric field effects on screening and long-range interactions to asymmetric and multi-species electrolytes.

Findings

Electric fields disrupt screening in asymmetric electrolytes.

Long-range repulsive interactions emerge under strong electric fields.

Charge density fluctuation correlations decouple in complex electrolytes.

Abstract

It is well established that the long-range component of the thermal van der Waals interaction between two semi-infinite dielectrics becomes short-range when an electrolyte is present between them, this is the well known phenomenon of screening. In Phys. Rev. Lett, 133, 238002 (2024) it was shown that for a binary symmetric electrolyte, an electric field parallel to the dielectric boundaries disrupts screening and a long-range thermal repulsive interaction appears. At large applied fields this long-range repulsive interaction can be explained by the fact that the cations and anions have differing average drifts moving in opposite directions, leading to the correlation of charge density fluctuations between the two species to decouple. Here we extend these results to binary electrolytes which are asymmetric as well as electrolytes with more than two ionic species.