Air-Dried Supramolecular Thermoresponsive-Assembled Biomass Aerogel: Superior Thermal Insulation, Flame Retardance, and Full Life-Cycle Sustainability

Biomass aerogels, considered promising sustainable alternatives to petroleum-derived insulators, highly depend on permanent covalent networks and energy- and resource-intensive drying processes to achieve multifunctionality. However, those features engender environmentally unsustainable manufacturing cycles and end-of-life disposal challenges. To tackle those issues, a facile and low-carbon air-drying method, assisted by supramolecular reversible assembly, was established for casting multifunctional biomass aerogels with high sustainability in the whole life cycle. By exploitation of the thermoresponsive supramolecular gels, the emulsified bubble templates within physical gels are significantly trapped, facilitating the fabrication of aerogels via air drying. Featuring a fiber-assembled secondary structure within the bubble-like pore architecture, this full biomass aerogel also manifests superior thermal insulation (30.4 mW m^–1 K^–1), high modulus (6.5 MPa), and flame retardance. Notably, benefiting from the thermoresponsive cross-linking networks, the full biomass aerogels exhibit full life-cycle sustainability, such as green fabrication, reparability during usage, closed-loop recyclability, and biodegradability after service life. The reused aerogels manifested comparable thermal conductivity (31.9 mW m^–1 K^–1) and compression modulus (4.6 MPa). This work eliminates the use of toxic reagents as well as energy- and resource-intensive procedures in both manufacturing and recycling, offering an environmentally benign strategy for fabricating next-generation biomass aerogels with high performance and less carbon footprint.