New water repellent material sheds like a snake when damaged

Scientists have taken inspiration from nature to create a water repellent material that sheds if damaged to reveal another hydrophobic layer.

Scientist Jürgen Rühe from University of Freiburg – IMTEK and his colleagues have reported to the Langmuir journal published by the American Chemistry Society (ACS) to reveal they have created a water repellent material that sheds its outer layer when damaged. The scientists copied the water-repelling structure of lotus leaves and water striders to develop the superhydrophobic material.

The material could be useful in a range of ways including rain gear, medical instruments and self-cleaning car windows. Most similar prototypes to date have not been strong enough to withstand damage by sharp objects. The researchers took inspirations from snake and lizard skins, and stacked three layers to create their material, using nanograss on the top, a water-soluble polymer in the middle, and a superhydrophobic silicon nanograss film on the bottom.

Nanograss consists of tiny needle-like projections sticking straight up. The team scratched the coating and submerged the material in water, which then seeped into the cut and dissolved the polymer. The top layer then peeled off like snake skin, exposing the bottom, water-repellent film. More work is needed to strengthen the top coating so that a scratch cannot penetrate all three layers, but Rühe and his team say it offers a new approach to creating self-cleaning and water-repellent materials.

Scientific development in the creation and repurposing of materials has helped make a number of new products, such as turning plastic bottles into soft fiber woven shoes and the creation of smart bandages that feedback to medical professionals, made using nanotechnology and biochemistry. Where is there a gap in the market for the next innovative material?