Molecular chaos powers potent ice-busting coating

Scraping ice off your car window might get a lot easier in the future thanks to a new spray coating developed by scientists in Austria. That's because of the way the molecules line up – or don't – during its high-tech creation process.

While anti-ice coatings aren't new, there have always been problems with them, says a research team at Austria's Graz University of Technology (TU Graz). Primarily, they can often detach from the surfaces they are meant to keep free from freezing.

So researchers there set out to improve upon the process. They used a manufacturing technique known as initiated chemical vapor deposition, or iCVD. It works by applying two substances as a gas onto a surface in need of coating. The process has been used over the years for everything from converting carbon dioxide to graphene to making better lithium-ion batteries.

In this case, a highly adhesive primer was combined with an icephobic polymer. As the gas was laid down on the surface, it consisted mainly of the primer, which allowed it to make a super-strong bond with the surface. As the spray process continued, the researchers increased the amount of ice-resistant material from zero to 100% of the mix. The result was a dual-layer coating that had a strong bond underneath and an outer surface that stopped ice crystals from forming.

The mechanism that created this ice-busting effect has never been seen before, say the researchers. They found that the molecules in the coating arranged themselves in random horizontal and vertical patterns that stymied the formation of ice.

"The ice-repellent material consists of elongated molecules that adhere to the primer in a vertical or horizontal orientation," explained study co-author Gabriel Hernández Rodríguez from TU Graz's Institute of Solid State Physics. "The thicker we applied the material, the more random the alternation between vertical and horizontal molecules became. And the more random the arrangement at the surface, the greater the ice-repellent effect."

The team was able to show that its coating was able to not only reduce ice adhesion levels, but lower the freezing point of water touching it as well.

While car owners in cold climates can dream of using the spray to coat car windows and make frosty freezing mornings a little easier, the researchers have other ideas in mind for the spray such as speeding up the de-icing of aircraft and keeping delicate sensing equipment free from frost.

The research has been published in the journal, ACS Applied Materials & Interfaces. 

Source: TU Graz