Scientists have developed an ultra-white coating that has the potential to revolutionize how we manufacture and apply paint. Developed from cellulose, it is remarkably thin and lightweight, and scatters light extremely well to achieve an incredibly bright white. As it is nontoxic and edible, the coating could even be used in the cosmetic, food, and pharmaceutical industries.
To produce this super-white substance, the team of researchers from the University of Cambridge and Finland’s Aalto University took a cue from nature. The material — which currently doesn’t have a name — mimics the structure of scales that cover the Cyphocilus beetle, a pallid bug that’s native to Southeast Asia. These scales, which are very thin, are formed from a dense and complex network of chitin, which scatters all wavelengths of light very efficiently; it is this particular exoskeleton that makes Cyphochilus appear so white.
Using small strands of cellulose, or cellulose nanofibrils, that were processed by mechanical defibrillation, the researchers engineered a flexible membrane with the same capability. They detailed their results in a study published this month in the journal Advanced Materials. The membrane, consisting of a particular combination of nanofibrils of varying diameters, is one of the thinnest materials developed so far that’s able to produce white. Just a few millionths of a meter thick, it scatters light 20 to 30 times more efficiently than white paper. The structure is “almost like spaghetti,” Dr. Silvia Vignolini, a Cambridge University researcher, said.
“What is cool is that with a really low amount of material, you can achieve a high intensity of reflection and whiteness,” Vignolini told Hyperallergic. “You don’t need to have thick material to have get 100% white, 100% reflection.”
While the researchers have processed the nanofibrils to create a flimsy membrane, they’re trying to find a way to produce a material for practical use, including as a paint for artists.
“Ideally we would like to make a powder that can be readily used and applied directly as you would do with a standard pigment,” Vignolini said. Once mixed into an organic solvent such as linseed oil, the coating would produce a bright white with just one layer, making the painting process less laborious in many cases.
Most white products that are commercially available, from paints to sunscreen, contain titanium dioxide and zinc oxide. While these materials are considered safe to apply, they are not sustainable, the researchers say (studies also argue that titanium dioxide nanoparticles pose a health risk). A coating developed from cellulose — which is naturally abundant, strong, and biocompatible — and reflects light extremely efficiently, represents a compelling alternative to current colorants.
The scientists hope to further optimize the coating’s whiteness by manipulating the configuration of nanofibrils. They will eventually try to manufacture it into a powder, which Vignolini says will likely sell at a pretty cheap price. Unlike Vantablack, you’ll be able to apply it yourself, like any other paint on your palette.
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