Rice University scientists have created graphene nanoribbons coated with epoxy. In trials, the ribbon has proved effective for melting ice on helicopter blades. The coating acts as a “real-time” de-icer.
For the study the researchers spread a thin coat of the composite on a segment of rotor blade.
The effectiveness of the coating was then demonstrated in laboratory trials. Here the coating repeatedly melted ice of several centimetres think at temperatures of close to zero. The melting effect happened once a voltage was applied to the coating. The voltage is low in terms of power, but it succeeded in creating sufficient electrothermal heat to rapidly melt the ice. The process is called Joule heating.
For helicopters in motion the coating also offers protection. Here a thin layer of water forms between the heated composite and the surface is sufficient to loosen ice leading it to drop off without it having to melt completely.
The heat conductive process was a consequence of graphene, which has excellent conductive properties. Graphene is a carbon based material that is light, flexible and strong. The material has a number of applications, including flexible screens and, as Digital Journal reported recently, being the basis for artificial skin with a possible application for next generation robots.
The nanoribbons were created by unlocking nanotubes, to create the transparent coating. The nanoribbon coating could have other uses, such as wind turbines and power transmission lines. The coating would be relatively straightforward to apply. The de-icing properties would also mean fewer chemical used. At present, large quantities of a chemical called glycol are used to operate machinery in sub-zero conditions.
Furthermore, the coating could help protect aircraft from lightning strikes, although more research is needed into this.
The research is published in the journal ACS Applied Materials and Interfaces. The paper is titled “Composites of Graphene Nanoribbon Stacks and Epoxy for Joule Heating and Deicing of Surfaces.”