Fabrication of Monolithic Para-Aramid Nanofibers/Cellulose Acetate Composite Aerogels with Homogeneous and Durable Cross-Linked Nanostructures for Filtration, Adsorption, and Drug Delivery

Aerogels with porous nanostructures and extremely low densities have drawn a lot of interest recently due to their huge potential applications, but it remains a great challenge to construct tough aerogels with controllable structures. Herein, monolithic composite aerogels consisting of para-aramid nanofibers (ANFs) and cellulose acetate (CA) were successfully fabricated through the "sol–gel-aerogel" process and supercritical fluid drying. The possible presence of complex and strong hydrogen bonds between ANFs and CA was verified by attenuated total reflectance-Fourier transform infrared (ATR-FTIR). To provide a thorough understanding of ANFs/CA composite aerogels, we carefully analyzed their gelation process, macromorphology, micromorphology, porosity, mechanical property, and adsorption capacity. The results show that CA plays a key role in the structural enhancement, porous morphology adjustment, and additional functionalities of the ANFs/CA composite aerogels. ACA-2 exhibited balanced performance across all samples, which has a specific surface area of 315 m2/g, an average pore diameter of 8.53 nm, a pore volume of 0.671 m3/g, a bulk density of 0.0269 g/cm3, a porosity of 98.03%, and a compressive modulus of 1.208 MPa. This work will contribute to the design and production of polymer-based fibrous aerogels with ideal chemical and physical properties. ANFs/CA composite aerogels may have considerable application potential in the fields of filtration, adsorption, and drug delivery.