The era of putting your phone into a container of rice after dropping it in water could be coming to an end. A new spray-on material provides exceptional waterproofing at lower cost, and its uses could extend far beyond household electronics.
Australian National University PhD student William Wong combined two plastics to create a highly water-repellent product. “It's like two interwoven fishing nets, made of different materials," Wong said in a statement. One plastic provides toughness, while the other offers flexibility. The product is sufficiently transparent, blocking just 15 percent of light, that it can be coated on windows.
Super-hydrophobic coatings like this are already in widespread use, but Wong said: "A lot of the functional coatings today are very weak.” Others break down when exposed to ultraviolet light.
Wong told IFLScience he tested his product by abrading it and exposing it to UV radiation 100 times more intense than it would experience in nature. He also dipped coated material in one molar hydrochloric acid for 24 hours. After drying, he found no damage done. Even oil, which can permeate the material, has no lasting effects once removed.
The tests have been published in Applied Materials and Interfaces. Such a long-lasting product could remove the need for cleaning windows, since any water will roll straight off, taking dust with it, as well as preventing the fogging of mirrors or car windows. Sadly for Terry Pratchett fans, however, the hydrophobia isn't powerful enough to repel water at a distance.
Above, Wong's coating in action. Australian National University
Nevertheless, Wong told IFLScience the work is not yet complete, saying: “We want to find further additives to it so it lasts not just for years but for tens of years.” In the meantime, sources of venture capital are being sought.
Potentially, the most important application could be for solar panels. Perovskite solar cells are approaching the efficiency of silicon (and the two in combination can be better still) and could theoretically be made much more cheaply.
One of the major obstacles preventing perovskites from providing us with cheap and abundant clean energy is that the cells are easily damaged by water. Solar researchers have been hoping for a protective coating material with qualities similar to the one Wong has made.
It is less than three months since IFLScience covered another paper by Wong, in which he announced the creation of a strip that rolls itself into a straw on exposure to water. Although both are part of Wong's PhD, he told IFLScience they were “parallel projects” using different materials, although he had made an unsuccessful attempt to combine them.