An invisible waterproof material made of graphene was produced at the labs of the Rensselaer Polytechnic Institute. The innovative “fabric”, less than one nanometre thick, can protect the underlying material from water without altering its properties.
This innovation could help improve the performance of self-cleaning surfaces, lab-on-a-chip devices, and applications that require liquid drops to move on solid surfaces.
“In addition to creating a barrier against water, these ‘nano-drapes’ are transparent and bring about minimal changes to the underlying surface,” says professor Nikhil Koratkar, head of the study. “We created an ultra-pure ‘fabric’ that prevents water penetration into the surface texture, and shows interesting and potentially important technological implications for lots of applications in the field of micro and nanofluidics.”
The researchers observed that water placed on the “bare” surfaces spreads and generates large flat drops (which point out to a hydrophilic substrate). On the other hand, if the surface is coated with graphene, the drops take a spherical shape, as it happens with hydrophobic or water-repellent materials. Waterproof properties can be observed following the application of a single nano-drape (which is several centimetres long and, once applied, can only be detected using a powerful microscope), but the effect can be enhanced by overlapping a few additional layers that cover any cracks or flaws on the base sheet of graphene.
To create this very thin fabric, Koratkar and his team grew graphene on a copper substrate, then coated the material with a polymeric film and removed the copper using weak acids. Lastly, the sheet of graphene on the polymer layer was transferred to the surface requiring protection and the polymer was gently washed away with acetone. The result was an ultra-pure, transparent one-atom thick waterproof fabric.
The study was published in the review ACS Nano. Click here to read the abstract.
The Editorial Staff
Published on Tuesday, October 1, 2013