Reversible-gel-assisted, ambient-pressure-dried, multifunctional, flame-retardant biomass aerogels with smart high-strength-elasticity transformation

Abstract Bio-based aerogels, poised as compelling thermal insulators, grapple with intricate synthesis procedures and limited durability in harsh conditions. Integrating smart stimuli-response transitions in biomass aerogels holds promise as a solution, yet remains a challenge. Here, we introduce a pioneering strategy, employing reversible-gel-assisted ambient-pressure drying without organic solvents, to craft multifunctional bio-based aerogels. Exploiting the thermally reversible gelling propensity of select biomasses, we anchor emulsified bubbles within cross-linked hydrogels, circumventing surface tension issues during mild drying. The resultant aerogels feature a robust porous matrix imbued with stable bubbles, yielding a low thermal conductivity, high flame retardancy, and robust resistance to diverse rigors. This innovative approach facilitates a paradigm shift in intelligent fire protection, where aerogels transition from robust to flexible in response to water stimuli, effectively shielding against thermal hazards and external forces. This work opens up a facile, eco-friendly, and mild way for fabricating advanced biomass aerogels with stimuli-responsive transformation.