Electrically controlled water permeation through graphene oxide membranes

TL;DR

This paper demonstrates the first experimental realization of electrically controlled water permeation through graphene oxide membranes, enabling precise regulation of water flow via electric field-induced water ionization.

Contribution

It introduces a novel method to control water permeation in GO membranes using electric breakdown to create conductive filaments that modulate ionization and flow.

Findings

Electric breakdown creates conductive filaments in GO membranes.

Electric field around filaments controls water ionization and permeation.

Water flow can be switched from ultrafast to blocked.

Abstract

Developing 'smart' membranes that allow precise and reversible control of molecular permeation using external stimuli would be of intense interest for many areas of science: from physics and chemistry to life-sciences. In particular, electrical control of water permeation through membranes is a long-sought objective and is of crucial importance for healthcare and related areas. Currently, such adjustable membranes are limited to the modulation of wetting of the membranes and controlled ion transport, but not the controlled mass flow of water. Despite intensive theoretical work yielding conflicting results, the experimental realisation of electrically controlled water permeation has not yet been achieved. Here we report electrically controlled water permeation through micrometre-thick graphene oxide (GO) membranes. By controllable electric breakdown, conductive filaments are created in the GO membrane. The electric field concentrated around such current carrying filaments leads to controllable ionisation of water molecules in graphene capillaries, allowing precise control of water permeation: from ultrafast permeation to complete blocking. Our work opens up an avenue for developing smart membrane technologies and can revolutionize the field of artificial biological systems, tissue engineering and filtration.