Hierarchically organized biomimetic architectured silk fibroin-ceramic based anisotropic hybrid aerogels for thermal energy management

Abstract

Due to the current energy crises, the search for thermal energy management systems based on thermal insulating porous materials has drawn a significant deal of attention. Herein, we demonstrated the thermal insulation and management capabilities of cuttlefish bone mimetic aerogels with hierarchically organized porous structures directly fabricated from surface modified and self-assembled silk fibroin biopolymer extracted from b. Mori silkworm cocoon biomass hereafter, the materials developed referred to as X-AeroSF. Exploiting from creating an interpenetrating network of the secondary ceramic components of various one, two, and threedimensional sepiolite (Mg2H2Si3O9.xH2O), MXene (Ti3C2TX) and silica nanostructures inside the self-assembled silk fibroin biopolymer and subsequent uni-directional freeze-casting and drying the resulted hydrogels, composites with aerogel feature were obtained. The obtained aerogels possess low bulk density (0.059-0.090 g cm-3), low thermal conductivities (0.035-0.042 W m-1 K-1), and high thermal stability (up to ~ 260 °C) with multi-modal lamella-bridge porousmicrostructures found in the cuttlefish bone structure. In addition, the intriguing anisotropy in the X-AeroSF composites porous structure enables thermal dissipation along with the aligned pore directions, thus decreasing the local overheating on the heated side. As a result, an improvement in thermal insulation in the perpendicular direction with respect to the pore lamellae was obtained. Therefore, the exquisite thermal energy management, biodegradability, low bulk density, fire resistivity, together with possible manufacture scalability of X-AeroSF composite, make this material attractive for future practical applications