Penn State flush with success in bio-inspired engineering

Pennsylvania researchers have developed a bio-inspired toilet bowl coating that dramatically reduces the amount of water needed to flush a toilet.

It’s the latest breakthrough from Penn State’s Wong Laboratory for Nature Inspired Engineering, housed within the Department of Mechanical Engineering and the Materials Research Institute. The laboratory focuses on utilising biologically-inspired concepts to design functional and adaptive interfacial materials with applications related to energy, water, and health – three important elements for sustainability.

The lab exploits the knowledge of two of Pennsylvania’s key industries – advanced manufacturing and materials, and life sciences. 

The Wong Laboratory for Nature Inspired Engineering’s research also includes bio-inspired projects such as emulating the ultra-slipperiness of pitcher plants for the creation of ultra-repellent surfaces, the self-cleaning of lotus leaves in liquid-repellent fabrics and friction-reduction surfaces, and investigating the tunable-adhesion of gecko feet, and the water desalination of mangrove.

Tak-Sing Wong, Wormley Early Career Professor of Engineering and associate professor of mechanical engineering and biomedical engineering, says: “Our team has developed a robust bio-inspired, liquid, sludge- and bacteria-repellent coating that can essentially make a toilet self-cleaning.”

Co-developed by Jing Wang, a doctoral graduate from Wong’s lab, the liquid-entrenched smooth surface (LESS) coating is a two-step spray that, among other applications, can be applied to a ceramic toilet bowl to create a super smooth and slippery surface.

The first spray, created from molecularly grafted polymers, grows molecules that look like little hairs, with a diameter about 1,000,000 times thinner than a human’s. The second spray infuses a thin layer of lubricant around those nanoscopic “hairs”. The coating ensures fecal matter slides down and does not stick to it, meaning the toilet can be flushed to dispose waste using a fraction of the water previously needed.

The researcher’s also found the surface effectively repelled bacteria, particularly ones that spread infectious diseases and unpleasant odours, which could reduce health concerns in waterless toilets or urinals.

The LESS coating is now being brought to market by startup spotLESS Materials in a bid to help sustain the world’s water resources.

“As a researcher in an academic setting, my goal is to invent things that everyone can benefit from,” Wong said. “As a Penn Stater, I see this culture being amplified through entrepreneurship, and I’m excited to contribute.”


(Via PSU, Wong Laboratory