Scientists have reproduced the structure of the scales of white elytra of beetles and obtained the "whitest" material available.
The "blackest material" in the world of Vantablack - so black that the objects covered with it cease to distinguish the objects of the eye as three-dimensional forms - has a worthy antipode. Scientists from Great Britain and Finland have obtained a new structurally colored material that is brighter than any artificial color. And for this, they drew attention to white insects that live in Southeast Asia.
Cyphochilus are widely known for their bright white shells. Back in 2014, Silvia Vignolini and her colleagues linked the unusual color of these beetles to the optical anisotropy of densely arranged sclerotin fibers, a modified form of chitin, in their rigid elytra. This structure provides equally effective scattering of photons of different wavelengths. As a result, the whiteness of these insects exceeds the whiteness of any artificial material, which is usually colored for this by pigments containing titanium dioxide or zinc oxide.
Now, Vinolini and her co-authors have managed to obtain an artificial analogue of the Cyphochilus elytra, a structurally colored white material, which they write about in an article published in the journal Advance Materials. Scientists have reproduced the chitin structure using cellulose strands, which can be manipulated much better in production. In this way, they obtained cellulose membranes of varying degrees of transparency, depending on the combination of threads of different thicknesses, and achieved the "maximum white" version.
Cyphochilus beetles and a sample of "structurally" white cellulose membrane / & copy; Olimpia Onelli, University of Cambridge
Like the reflecting surface of beetle scales, the resulting membranes are extremely thin - on the order of micrometers. However, measurements carried out by the authors showed that they reflect mixed white light 20-30 times more efficiently than the highest quality bleached paper. Scientists are confident that they will soon be able to refine the technology and bring it to practical use, as the creators of the "radical black" Vantablack did a few years ago.
Sergey Vasiliev
