A groundbreaking innovation in bathroom technology promises to reduce water waste while improving hygiene dramatically. Scientists have developed an ultra-slippery surface treatment that could make toilet brushes obsolete and slash global water consumption by billions of liters daily
The science behind the slickness
Researchers at Penn State University have engineered a spray-on coating that outperforms even Teflon in slipperiness. This remarkable material, dubbed ‘Less’ (an acronym for liquid-entrenched smooth surface), reduces waste adhesion by an impressive 90%, meaning toilets require far less water to flush clean.
As explained here, the innovation emerged from an unexpected collaboration. In 2015, researchers at Cranfield University reached out to Tak-Sing Wong, whose team specialized in creating surfaces that repel sticky substances. They faced a persistent challenge: designing a toilet for developing nations that wouldn’t accumulate odorous residue. This partnership sparked years of research that would ultimately benefit households worldwide.
How the coating works
The technology operates through a sophisticated two-layer system. The base layer bonds to the toilet bowl surface and features microscopic ‘nanohairs’—structures so fine that each one measures just a billionth of a human hair’s thickness. These nanohairs serve as anchors for the second layer: a thin film of silicone oil that creates the supremely slippery surface. Remarkably, the entire application process takes under five minutes.
Rigorous testing protocols
To validate their invention, the research team conducted extensive and unconventional experiments. They began by preparing synthetic waste using a South African recipe, creating samples of varying consistencies. These samples were dropped from a height of 40 centimeters onto test surfaces angled at 45 degrees, mimicking real-world conditions. Using fluorescent dye as a tracer, they measured the water volume required to eliminate all visible residue.
The results were striking: the coated surfaces needed 90% less water than ordinary glass to achieve complete cleanliness.
For the second phase of testing, the team constructed a mechanical apparatus to test real human waste from three anonymous volunteers. This rig dropped samples onto horizontal surfaces made from various materials—ceramic, Teflon, silicone, and their proprietary coating. After allowing the waste to settle, the platform would swing downward like a trapdoor, revealing which surfaces retained residue and which shed it cleanly.
In findings published in Nature Sustainability, Wong and his colleagues documented how conventional materials demonstrated ‘extreme stickiness,’ while their coating appeared to release waste without leaving traces. Wong has since co-founded a company to commercialize the technology.
Beyond cleanliness: Hygiene benefits
Additional experiments revealed that the coating outperforms standard toilet surfaces in preventing bacterial growth from multiple sources—including waste, urine, and even rainwater. This antimicrobial advantage could significantly reduce the spread of disease-causing pathogens in both homes and public facilities.
Durability and maintenance
While the coating proves resilient enough to withstand 500 standard flushes, testing suggests it may require reapplication after approximately 50 urination cycles. This maintenance requirement represents one area for future improvement as the technology matures.
Environmental Impact and Global Significance
The environmental implications are staggering. According to Wong’s calculations, over 141 billion liters of fresh water go down toilets globally each day—nearly six times Africa’s entire daily water consumption. With millions facing severe water scarcity worldwide, reducing flush volumes could provide meaningful relief to stressed water systems.
‘This represents an elegant application of materials science to a universal problem,’ noted Mark Miodownik, professor of materials and society at University College London. ‘We’re all familiar with non-stick cookware preventing eggs from adhering to pans. This technology applies similar principles to waste adhesion in toilet bowls.’
Outstanding questions
Miodownik raised an important consideration for future research: the environmental fate of coating materials as they inevitably degrade through use. ‘Such toilets would clearly use less water per flush and improve hygiene,’ he observed. ‘However, we must understand what happens to the coating chemicals as they wear away—particularly the potential environmental consequences if this technology achieves global adoption.’
This concern highlights the need for lifecycle analysis and environmental impact studies as the technology moves toward widespread implementation. Nevertheless, the coating represents a promising step toward more sustainable sanitation practices in a water-constrained world.