Thermally super-insulating nanofibrous curdlan aerogels with low shrinkage.

Pure curdlan aerogels were synthesized utilizing heat-induced gelation, solvent exchange, and supercritical carbon dioxide (sc-CO2) drying by modulating the self-assembly of its polymer structure. The nanofibrous structure of the gel was optimized through a gradient methanol/ethanol exchange. Comprehensive analyses were conducted to evaluate the envelope density, morphology, specific surface area, pore size distribution, thermal conductivity, as well as the compressive and tensile mechanical properties of the aerogels. The findings indicate that curdlan aerogels exhibit three notable characteristics, including low shrinkage (less than 8 %), low density (ranging from 17.9 to 58.7 mg cm-3), and low thermal conductivity (between 21.6 and 25.1 mW m-1 K-1), which are very interesting among polysaccharide aerogels. Further structural analysis indicates that the multi-level pore size distribution with diverse pore diameters in curdlan aerogel, formed during the solvent exchange process due to the aggregation and fracture of gel fibers. Given that curdlan is extensively utilized in biomedicine and food industries, the integration of these properties with aerogels presents substantial potential for future applications.