Nanofluidics concerns the transport, behaviour and control of fluids on a tiny scale, which results in different properties from those observed in everyday examples. Nanofluidic devices use small channels to move ions in electrolytic solutions, and this makes them a good prospect for use in batteries or systems for water purification.
By using many layers of graphene oxide paper, research published in the Journal of the American Chemical Society has found that a supple ‘paper’ is formed, with tens of thousands of channels working through it – a small gap about one nanometre high forms between neighbouring sheets, and through this ions can move. This paper can then be cut into the required shape with a pair of scissors – for the study a rectangle was used, and electrodes attached to either end of the polymer encased strip of graphene oxide. A higher than normal current was recorded, since the channels have a concentrating effect, and the device worked whether flat or not.
Graphene oxide is more commonly used to make graphene or utilised for its mechanical properties. But here is a new method which could really put this inexpensive material to good use, whether on a small or large scale, since there is no limit to the number of sheets which can be stacked, and therefore the number of channels which can be created.