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

Bio-based aerogels, which are poised as compelling thermal insulators, demand intricate synthesis procedures and have limited durability under harsh conditions. The integration of smart stimuli-response transitions in biomass aerogels holds promise as a solution, yet remains a challenge. Here, we introduce a pioneering strategy that employs reversible-gel-assisted ambient-pressure drying without organic solvents to craft multifunctional bio-based aerogels. By 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 that is imbued with stable bubbles, yielding low thermal conductivity, high flame retardancy and robust resistance to diverse rigors. This innovative approach facilitates a paradigm shift in intelligent fire protection in which 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 to fabricate advanced biomass aerogels with stimuli-responsive transformation.