The scientists called the liquid-secreting material ‘self-lubricating organogels’, or SLUGs. "We came upon this idea when we observed real slugs in the environment," Chihiro Urata, a researcher in the Durable Materials Group at AIST, explained. "They secrete a liquid mucus on their skin, which repels dirt, and the dirt slides off. From this, we started focusing on the phenomenon called syneresis, the expulsion of liquid from a gel."
The gel and the liquid-repellent substance are held in a matrix of silicone resin. The mix is cured and applied to a surface as a nearly transparent and solid film coating.
The team examined the anti-icing properties of several types of organogels under tests at various temperatures. The discovery of the material's thermo-responsive secretion properties was an unexpected surprise. The tests also showed that the secretion was a reversible process. The syneresis gradually starts when temperatures fall below freezing. So although ice can still form, it cannot adhere to the surface and it slips off. Once the temperature rises above freezing, the liquids return back to the film.
Urata sees potential applications for SLUGs beyond aircraft and singles out antifouling coatings in packaging, paints, ship bottoms, metal moulds and signage.