Pickering Emulsion-Mediated Interfacial Assembly of Lightweight and Rapid Rebound CNF/PMSQ/ECH Aerogels

Lightweight and highly resilient biobased aerogels are attractive for advanced porous materials, yet achieving ultralow density and rapid elastic recovery simultaneously remains challenging. Herein, a Pickering emulsion-mediated interfacial assembly strategy is developed to fabricate lightweight and rapid rebound cellulose nanofiber/polymethylsilsesquioxane/epichlorohydrin (CNF/PMSQ/ECH) hybrid aerogels. Carboxymethyl cellulose nanofibers (CMCNFs) serve as both emulsion stabilizers and structural scaffolds, enabling the in situ hydrolysis and condensation of methyltriethoxysilane (MTES) at the emulsion interface and promoting the uniform integration of the PMSQ phase within the cellulose framework. Subsequent epichlorohydrin cross-linking further reinforces the interconnected porous network, resulting in aerogels with an ultralow density of 41.6 mg·cm-3, engineered hydrophobicity, and excellent mechanical resilience. Benefiting from the synergistic effect of the PMSQ framework and the cross-linked cellulose network, the aerogels achieve rapid elastic recovery within 34 ms and a rebound velocity of 324.5 mm·s-1. As a proof-of-concept demonstration of their functional potential, the aerogels also exhibit reproducible strain-dependent piezoresistive responses for human motion monitoring. This work provides an effective strategy for constructing lightweight and rapid rebound cellulose-organosiloxane hybrid aerogels through Pickering emulsion-mediated interfacial assembly.