Electrically controlled water permeation through graphene oxide membranes
Authors: K G Zhou, K S Vasu, C. T. Cherian, M. Neek-Amal, J C Zhang, H Ghorbanfekr-Kalashami, K Huang, O P Marshall, V. G. Kravets, J Abraham, Y Su, A N Grigorenko, A Pratt, A K Geim, F M Peeters, K S Novoselov, R R Nair
Publication Date: 11 July, 2018
Graphene smart membranes can control water
Developing smart membranes with a stable and reversible response to external stimuli is a long-sought objective for scientists and technologists due to its importance in fundamental sciences and its potential for a wide variety of applications ranging from filtration and separation technology to healthcare. Fabrication of smart membranes with precise control of the permeation of water and other molecules has also been on the wishlist of manufacturers, but until now, has not been achieved experimentally. Such membranes would be of particular interest for life-science and healthcare applications, as they can mimic the performance of natural membranes. Ultimately, such technology could be applied for tissue engineering and for the creation of artificial membranes with biological functions.
Now, for the first time, researchers at the University of Manchester, with collaborators in Antwerp, Tehran and York have demonstrated electrically-tunable water transport through micrometre-thick graphene oxide (GO) membranes. To achieve electrical control over water permeation, the researchers created conductive filaments in the graphene oxide membranes via controllable electrical breakdown. The electric field that concentrates around these current-carrying filaments ionizes water molecules inside graphene capillaries within the graphene oxide membranes, which impedes water transport. This work opens up an avenue for developing smart membrane technologies for artificial biological systems, tissue engineering, and filtration.
- Membranes are selective barriers that can separate molecules or compounds with different physicochemical properties.
- Graphene oxide membranes have previously been shown to exhibit ultrafast permeation of water and molecular sieving properties, with the potential for industrial-scale production.
- The stimuli-responsive membrane or smart membrane is capable of controlling its permeation properties in response to changes in the external stimuli such as electrical current/voltage, temperature, pH or chemical composition.
- The presence of moisture is known to facilitate the formation of conducting paths (generally carbon) across insulators under the large electric field. We used this phenomenon to introduce thin conductive filaments in graphene oxide membranes.