Nano-thin ‘liquid-like’ coatings pave the way for a self-cleaning world
A biodegradable alternative to ‘forever chemicals’ with numerous applications. Droplets on a slippery surface [Credit: Isaac Gresham] University of Sydney researchers have observed oil molecules retaining their ‘liquid-like’ properties when they are chemically attached as an extremely thin layer to solid surfaces, opening new possibilities for designing sustainable materials with non-stick characteristics. The findings are published in the leading chemistry journal Angewandte Chemie, led by Dr Isaac Gresham with co-authors Professor Chiara Neto and honours student Seamus Lilley from the School of Chemistry and Sydney Nano, Dr Kaloian Koynov from the Max Planck Institute for Polymer Research and Dr Andrew Nelson from the Australian Centre for Neutron Scattering. The ‘liquid-like’ coatings the team studied, known as slippery covalently-attached liquid surfaces (SCALS), are produced from silicones or polyethylene glycol – both of which break down into harmless byproducts in the environment. SCALS are anti-adhesive without relying on problematic perfluorinated polymers (PFAS), known as ‘forever chemicals’ that are usually used for their low adhesion properties. “These liquid-like layers are extremely slippery to most contaminants: they shed liquid droplets effortlessly, which is great to increase the efficiency of heat transfer and for collecting water, they prevent the buildup of scale, and resist the adhesion of ice and bacteria, bringing us one step closer to a self-cleaning world,” said Professor Neto, who leads the Nano-Interfaces Laboratory at the University of Sydney. “We can correlate the exceptional performance of these layers with their nanostructure – meaning we now know what we’re aiming for when we design slippery surfaces, enabling us to make them even more effective and provide viable alternatives to fluorinated coatings.” The slippery nano-thin layers, between two and five billionths of a metre thick or 10,000 times thinner than a human hair, are made up of oil molecules that are only a hundred atoms long. “A water droplet glides with no friction over a thick […]