An Artificial Chameleon Skin for Dynamic Thermoregulation

Abstract

Abstract Solar radiation is the major energy source for most living creatures, and some creatures change their skin colors responding to energy demands. Inspired by the chameleons that live in the desert of Namibia, which can regulate body temperature by changing skin colors between black and white, a patterned hydrogel film with self‐thermoregulation ability is reported in this work. The film consists of two parts: a light‐responsive black part and a stretchable white part. The black part is made of thermoresponsive poly(N‐isopropylacrylamide) hydrogel with polydopamine (PDA) nanoparticles, and the white part is made of stretchable polyacrylamide hydrogel with polystyrene (PS) nanoparticles. At low temperature and low light irradiation, the black part dominates the film, and the embedded melanin‐like PDA nanoparticles adsorb light and convert it to heat, thus reaching an active body temperature. At high temperature and strong light irradiation, the black part shrinks, which in turn stretches the white part to dominate the film, and more light is reflected by guanine crystals‐like PS nanoparticles, thus protecting body temperature from rising. The combination of the thermoresponsive black hydrogel and stretchable white hydrogel provides an evolutionary novelty that can control the solar lights for dynamic thermoregulation.

Keywords

• hydrogel
• reflection
• solar–thermal conversion
• thermoregulation
• thermoresponsive