Controlling the composition of a confined fluid by an electric field

TL;DR

This paper introduces a novel method to control the composition of confined fluids using electric fields, combining pore sensitivity and field effects, demonstrated through Monte Carlo simulations.

Contribution

A new approach that modulates confined fluid composition via electric fields without altering bulk conditions, applicable to colloids and molecular fluids.

Findings

Composition can be controlled continuously or jumpwise.

Electric fields induce population inversion near demixing instability.

Method is robust and based on generic mechanisms.

Abstract

Starting from a generic model of a pore/bulk mixture equilibrium, we propose a novel method for modulating the composition of the confined fluid without having to modify the bulk state. To achieve this, two basic mechanisms - sensitivity of the pore filling to the bulk thermodynamic state and electric field effect - are combined. We show by Monte Carlo simulation that the composition can be controlled both in a continuous and in a jumpwise way. Near the bulk demixing instability, we demonstrate a field induced population inversion in the pore. The conditions for the realization of this method should be best met with colloids, but being based on robust and generic mechanisms, it should also be applicable to some molecular fluids.