Chameleon inspired colour-change coating
Thermally responsive photonic crystals (TRPCs) are intelligent responsive materials that can dynamically coordinate electromagnetic wave transmission, translating thermal stimuli into optical signals and structural color changes. However, it remains a big challenge to develop a robust TRPC, because of the thermochromic mechanism of unstable dramatic volume change that collapses photonic crystal (PC) structure.
Negligible colour fluctuation
Researchers now demonstrate a highly robust and flexible TRPC film inspired by the chameleon, combining thermochromic dyes (TDs) with PC for a synergistic response. There is only negligible colour fluctuation even after 2000 colour-change cycles, attributing to no lattice parameter change during the thermal stimulus. Moreover, both positive (transparency to opaque colour) and negative (opaque colour to transparency) TDs are introduced into TRPC, implementing a full-colour RGB thermally-responsive system. The response of the positive-TRPC and negative-TRPC temperatures were 32.0 and 50.5 °C, respectively. A TRPC film with environmental adaptability was designed, which offers a promising route to anti-counterfeiting, steganography and smart window.
The study has been published in Progress in Organic Coatings, Volume 183, October 2023.