A simple route to water-repellent graphene

A simple gas-phase method produces a form of graphene whose ability to repel water rivals that of lotus leaves. The finding may lead to an inexpensive way to make bulk quantities of the material for applications in self-cleaning surfaces as well as in coatings that resist icing and marine biofouling.

Lotus leaves’ knack for shedding water droplets has inspired many researchers to engineer materials with similarly hydrophobic surfaces. One approach involves patterning 3D microstructures that mimic the lotus leaf surface and capping them with a hydrophobic material. Another is based on growing graphene on a substrate, then adding hydrophobic functional groups or processing the graphene in other ways.

M. Weston Miller, Makenna Parkinson, and Albert Dato of Harvey Mudd College have come up with a simpler way to make superhydrophobic graphene. By injecting an ethanol-argon aerosol into a commercial plasma generator, the team made graphene directly in the gas phase (ACS Materials Lett. 2022, DOI: 10.1021/acsmaterialslett.2c00125).

Microscopy analysis reveals that the plasma-generated powder consists of crumpled, randomly oriented graphene sheets. And tests measuring contact angles, roll-off angles, and bouncing characteristics show that water droplets on the untreated graphene exhibit nearly the same behavior they do on lotus leaves.