Now scientists at Dalian University of Technology have developed a new structure made of copper nanowires that can passively de-ice surfaces with an efficacy of close to 100%.

There's been no shortage of de-icing systems developed and tested over the years. Some require chemical coatings, while others involve nanoscale structures that don't allow water and ice to find a grip. Some use electricity to warm up surfaces infused with graphene or carbon nanotubes, while others are made of magnetic coatings that slide ice right off.

For the new study, the Dalian team designed assemblies of copper nanowires which have the benefits of warming surfaces without needing an artificial energy supply. Instead, they get their energy from sunlight, and are designed to effectively absorb and distribute that heat smoothly across the whole array.

Through a series of experiments, the team identified the most effective designs – upright nanowires with as little as a 2- or 3-micrometer gap between them. This allowed them to capture more than 95% of the sunlight that strikes them, and the high thermal conductivity of the copper allowed that to spread out efficiently. The end result was a superhydrophobic surface with a reported defrosting efficacy approaching 100%.

The team says that this technique seems promising, but admits that there may some issues with scaling up manufacturing that need to be overcome first.