Nanoporous carboxymethyl cellulose aerogels with enhanced thermal insulation and mechanical toughness

This study presents a facile method to fabricate nanoporous carboxymethyl cellulose (CMC) aerogels with exceptional thermal insulation properties through metal ion cross-linking and supercritical carbon dioxide (scCO₂) drying. The as-prepared aerogels exhibit remarkable characteristics, including low density (as low as 0.15 g cm^-3), high specific surface area (up to 303 m² g^-1), high compression strength (stress of 17.31 MPa at 80 % strain), and low thermal conductivity (as low as 21.7 mW (m K)^-1). The effects of varying CMC concentrations on the density, specific surface area, morphology, and thermal insulation properties of the aerogels were systematically investigated. This work highlights the potential for tailoring CMC aerogel properties by adjusting the initial CMC concentration, offering new opportunities for developing cost-effective thermal insulation materials.