Programmable Flexible Biomass Aerogels for Efficient Photothermal Conversion

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Biomass aerogels, with their sustainability, flexibility, and porous architectures, hold great promise for wearable photothermal energy conversion, yet their applications are limited by the lack of intrinsic photothermal functionality and the aggregation of plasmonic nanostructures within porous networks. Herein, a multifunctional plasmonic cellulose aerogel with programmable morphology was developed by integrating polyethylene glycol (PEG)-modified gold nanorods (GNRs) into a cellulose nanofiber (CNF) framework. PEG ligand exchange provides steric stabilization for GNRs, suppressing aggregation within the porous matrix and promoting plasmonic coupling. The resulting aerogel exhibits a hierarchical mesoporous structure with a high specific surface area of 486 m2 g–1 and an average pore diameter of ∼16.3 nm, while maintaining excellent mechanical robustness with an elongation at break of 35.4% and a Young’s modulus of ∼0.99 MPa. Under solar irradiation, the aerogel reaches 64.2 °C under 1 sun and 99.3 °C under 2 sun, showing efficient and stable photothermal performance. Electromagnetic simulations reveal that localized surface plasmon resonance and interparticle coupling generate spatially confined nanoscale hotspots, accounting for enhanced photothermal behavior. Rapid gelation further enables scalable fabrication of films, microspheres, and microfibers. This work provides a colloidal interfacial engineering strategy for scalable soft photothermal systems.