Engineers develop water-saving repellent coating

A repellent coating facilitating a more efficient flush and cleaner toilets, called liquid entrenched smooth surface (LESS), has been developed by engineers at the Penn State University. The main purpose of the repellent is to reduce the quantity of water required for the toilet to flush, while keeping the bowl clean, and the result is that the toilet only needs to use three litres of water instead of six.

A two-step spray process needs to be applied in order for the repellent to work. The primary spray is made from molecularly grafted polymers and builds a liquid repellent foundation which produces a smooth surface. Then after the second spray a larger repellent surface is created from the infusion of the thin coating of lubricant around the nanoscopic polymers.

Associate Professor of Mechanical Engineering and Biomedical Engineering at Penn State, Tak-Sing Wong, stated: “Poop sticking to the toilet is not only unpleasant to users, but it also presents serious health concerns. Our team has developed a robust bio inspired, liquid, sludge and bacteria repellent coating that can essentially make a toilet self-cleaning. Our goal is to bring impactful technology to the market so everyone can benefit. To maximise the impact of our coating technology, we need to get it out of the lab.”

A doctoral graduate from Wong’s lab, Jing Wang, stated: “When it dries, the first spray grows molecules that look like little hairs, with a diameter of about 1,000,000 times thinner than a human’s. When we put that coating on a toilet in the lab and dump synthetic faecal matter on it, it just completely slides down and nothing sticks to it.”