Cellulose, the most abundant renewable resource on Earth, has been used in countless applications since ancient times due to its ubiquitous presence, impressive structural properties, and high biocompatibility. In recent years, natural fiber welding (NFW) was introduced as a method for fusing cotton-derived cellulose using the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIAc), thereby welding strands of cotton thread (primarily crystalline cellulose I) into an amorphous mesoporous network. While these welded all-cellulose xerogels have immense application potential (e.g., from industrial filters to hosts for functional nanomaterials), there is currently a lack of fine control over the pore composition of the final structure. Herein, we demonstrate that the porosity of a welded cotton xerogel can be controlled by fine-tuning the solvent wash and drying steps. To accomplish this, a commercial nonfluorescent cotton thread is subjected to the NFW process using neat EMIAc, followed by solvent exchange with one or more solvents of varying polarities (i.e., single or step-wise solvent rinses). The welded, solvent-saturated cellulose xerogels are then dried in vacuo at elevated (60 °C) or frozen conditions. Physisorption BET analysis is used to estimate surface area and pore distribution, with an exceptional surface area range of 0.1 – 170 m<sup>2</sup> g<sup>–1</sup> tuned solely by the solvent identity and drying conditions.

Effect of solvent wash procedure in controlling porosity in natural fiber welded Xerogels

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.