Chemical Engineering Science, Vol.196, 64-71, 2019
Leather enabled multifunctional thermal camouflage armor
Realizing persistent thermal camouflage of heat objects remains challenging. A variety of biological species have evolved extraordinary thermal insulation strategies that represent an exciting source of inspiration for developing high-performance thermal camouflage materials. However, we are still far from being able to faithfully mimic these natural insulation materials not only because of the difficulty to imitate the intricate structural hierarchy but also due to the challenge to simulate the way used by nature, that is, each level of structural hierarchy collaborates together to achieve efficient insulation. Instead of biomimicing the biological structures, we here make a direct structure editing on the natural insulation structure of cowhide for obtaining multifunctional thermal camouflage armor. SiO(2 )nanoparticles (SiO(2)NPs) were in situ grown on the 3D hierarchically fibrous scaffold of leather, which played multiple roles in trapping stagnant air as thermal insulator, blocking infrared absorptive groups and reflecting infrared radiation from heat objects. The thermal camouflage armor exhibited a high porosity to 61.4%, as well as low thermal diffusivity (1.24 x 10(7) m(2) s(1)) and thermal conductivity (0.04 W m(1) K-1). The thermal camouflage armor exhibited persistent camouflage performance (1.0 h) and exceptional non-thermal functionalities, including hydrophobicity, flame-resistance, flexibility and arbitrary tailorability. (C) 2018 Elsevier Ltd. All rights reserved.