Graphene smart membranes can control water

18 Jul 2018

Researchers at the National Graphene Institute (NGI) have achieved a long-sought-after objective of electrically controlling water flow through membranes

This is the latest exciting membranes development benefitting from the unique properties of graphene. The new research opens up an avenue for developing smart membrane technologies and could revolutionise the field of artificial biological systems, tissue engineering and filtration. 

Graphene is capable of forming a tuneable filter or even a perfect barrier when dealing with liquids and gases. New 'smart' membranes developed using an inexpensive form of graphene called graphene oxide, have been demonstrated to allow precise control of water flow by using an electrical current. The membranes can even be used to completely block water from passing through when required.

The team, led by Professor Rahul Nair, embedded conductive filaments within the electrically insulating graphene oxide membrane. An electric current passed through these nano-filaments created a large electric field which ionises the water molecules and thus controls the water transport through the graphene capillaries in the membrane. 

Prof Nair said: "This new research allows us to precisely control water permeation, from ultrafast permeation to complete blocking. Our work opens up an avenue for further developing smart membrane technologies."

"Developing smart membranes that allow precise and reversible control of molecular permeation usin external stimuli would be of intense interest for many areas of science; from physics and chemistry, to life-sciences."

Graphene and related two-dimensional materials have shown promise for developing new appliations as well as enhancing currently used processes for areas as diverse as; electronics, composites, sensors and biomedicine. Membranes have become a key research and development theme for desalination, gas separation and healthcare.