Cephalopod-inspired Mxene-SEBS/TiO2 composite film for synergistic solar and infrared radiative heat management

Abstract

Flexible biomimetic photonic structures, capable of achieving dynamic radiation modulation in both solar and infrared (IR) bands as required, are increasingly catering to low-energy thermal management and sustainable development. Herein, the cephalopod-inspired composite film of styrene-ethylene-butene-styrene block copolymer (SEBS)/titanium dioxide (TiO2)-Mxene has been designed and prepared. Analogous to squid leucophores, the SEBS/TiO2 layer of is able to regulate solar reflection and transmit infrared radiation. Mimicking squid iridocytes, the Mxene layer can regulate infrared reflection and absorb sunlight. The optimal structural parameters of the film and the regulation contrast were estimated via theoretical analysis. The theoretical design also illustrates that the two layers collaborate without interference. According to the optimal parameters, the Mxene-SEBS/TiO2 film was prepared. A dynamic regulation between radiative heating and cooling, namely, the solar reflection between 38 % and 66 % and infrared emissivity between 68 % and 89 % can be realized via mechanical actuation under 200 % strain. As the solar radiation is ∼650 W/m2, the composite film achieves ∼6.2 °C heating/∼1.4 °C cooling of the skin under mechanical actuation. When reducing the natural convection loss, the film further achieves ∼11.6 °C heating/∼0.8 °C cooling of the skin. This work provides a novel system and strategy for radiation modulation in solar-infrared bands for possible applications in thermal management.