Solvent-polarity-engineered hyaluronic acid aerogels: Synthesis of transparent nanofiber network for thermal
Yufang Lu1, Shanying Sui1, Miao Cui1
1Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, PR China.
Abstract:
Aerogels exhibit superior thermal management properties, while challenges in simple synthesis with mild reaction conditions, optical transparency, and flexibility limit their applications. This study presents a mild approach to produce transparent hyaluronic acid (HA) aerogels without the use of chemical cross-linkers. By regulating solvent polarity through methanol-isopropanol gradient exchange followed by supercritical drying, phase separation is induced, transforming HA molecular chains into a uniform nanofiber network. This structural evolution endows the aerogels with exceptional mechanical strength and flexibility while maintaining high transparency (90 % transmittance and 8.5 % haze at 600 nm). SEM analysis reveals the formation of a nanofiber network with an average diameter of 12.4 nm. Nitrogen adsorption measurements reveals a high surface area of 560.94 m2 g-1. The slender nanofiber network results outstanding thermal insulation, achieving an ultralow thermal conductivity of 0.0243 W m-1 K-1 at a low density of 0.074 g cm-3. This work highlights the critical role of solvent-induced nanofiber assembly in balancing optical and mechanical properties, positioning HA aerogels as sustainable candidates for optically transparent infrared stealth materials.
