Lightweight, Flexible, Thermally-Stable, and Thermally-Insulating Aerogels Derived from Cotton Nanofibrillated Cellulose

Aerogels with multiple advantages have been developed for various requirements, but aerogels tend to be fragile and easy to break when bent or compressed. Herein, high-aspect-ratio cotton-derived nano-fibrillated cellulose (NFC) was utilized as building blocks to construct aerogels. The cotton NFC formed strong web-like entangled structures that acted as the skeletal support of aerogels, exhibiting a density lower than that of wood-, bamboo-, and rice straw-derived NFC aerogels. The cotton NFC aerogels (CoNAs) were soft, flexible, and illustrated good resilience performance after compression release. The CoNAs had a high thermal stability arising from the component purity (similar to 100% cellulose) and high relative crystallinity of cotton NFC, demonstrating their application suitability in high-temperature conditions. Further, the CoNAs exhibited an excellent thermal insulating performance and insulation stability at various temperatures owing to their porous structures and high thermal stability. The CoNAs fabricated herein are thus expected to be a novel member of the nanocellulose aerogel family owing to characteristics attained by integrating multiple structural and performance advantages into the one.