Scientists at the U.S. Naval Research Laboratory (NRL) have moved liquid droplets using long chemical gradients formed on graphene.
The change in concentration of either fluorine or oxygen formed using a simple plasma-based process either pushes or pulls droplets of water or nerve agent simulant across the surface.
So why is this exciting, you ask? Because of this:
This new achievement offers potential applications ranging from electronics to mechanical resonators to bio/chemical sensors.
NRL scientists have shown that it is possible to create a chemical gradient on graphene, which pushes or pulls small drops of liquid. Gradients in the wettability of a material are widely found in nature, such as the famous lotus-leaf effect or in spider webs.
Researchers who study these effects have found that to be useful, the gradient must be especially smooth without defects that can snag the water droplet.
The effect has been achieved before with large molecules or polymers but not with graphene—a layer of carbon only a single atom thick. The chemical flexibility of that carbon enabled both oxygen and fluorine gradients to be created.