Seattle is home to two of the biggest names in the tech industry in Microsoft and Amazon, but it's also known for being one of the wettest cities in the U.S. One local artist is using a little technology and a lot of innovation in creating street art designed to cheer up his fellow Seattleites on rainy days.
Rainworks is what Peregrine Church is calling the series of invisible street art pieces littering Seattle, that are invisible most of the time but appear out of nowhere once it starts to rain. Church achieves the effect using superhydrophobic coatings, a technology inspired by the waterproofing found on lotus leaves and the feet of geckos.
Superhydrophobic coatings are materials that can make any surface completely water repellent. Church sprays concrete pavements around Seattle with a superhydrophobic spray called "Always Dry" using large stencils that he creates. 24 hours later the sections of the pavement sprayed are completely waterproof. When it starts to rain, the wet concrete pavement darkens in color but the sections covered in the coating remain light colored and dry, revealing Church's art. Each rainwork lasts about four months to a year, depending on the amount of foot traffic it has to endure.
It's hardly rocket science, but an innovative use of technology. "We make rainworks to give people a reason to look forward to rainy days," Church says on his website. "It's going to rain anyway. Why not do something fun with it". The site also includes a map that shows the locations of various rainworks around the Seattle area.
The waterproofing technology inspired by nature is sometimes referred to as the Lotus effect. The leaves of the lotus consist of micro- and nano-scale papillae that are coated in a hydrophobic wax which repels water. Geckos also secrete a superhydrophobic oil which is their secret to walking up walls. The oil keeps the pads on their feet incredibly clean, thereby allowing the creatures to stick to surfaces and move quickly at the same time.
Man-made superhydrophobic coatings were first developed in the '70s and '80s and are widely used in industry to keep certain materials dry. They're also used to coat the hulls of boats which helps reduce friction and therefore lower fuel costs. While this is no doubt a more productive use of the technology we're glad that these materials are now widely available in liquid gels or aerosol can sprays allowing artists like Church to put them to frivolous use.