Efficient fabrication of cellulose nanofibers with novel superbase-derived ionic liquid/co-solvents: Rapid cellulose dissolution and improved solution electrospinnability

Ionic liquids (ILs), well-known for their wide solubility, low volatility, and high chemical stability, can be an excellent alternative to volatile solvents commonly employed in micro/nanofiber fabrication. Herein, nanofibers were successfully fabricated through electrospinning of natural cellulose, which realized by a novel superbase-derived ionic liquid (SIL) complemented with dipolar aprotic solvents as co-solvents. The SIL/co-solvent systems with enhanced hydrogen-bonding basicity (>1.30) accelerated cellulose dissolution. Besides, the improved transport properties of SIL/co-solvent systems facilitated small ion clusters and free ions deeper penetration into the hierarchical cellulose structures, synergistically contributing to a high rate of cellulose dissolution. Furthermore, the solution electrospinnability systematically explored and the electrospinning process was optimized to achieve a continuous jet and minimize adhesion between wet filaments. Consequently, cellulose nanofibers with a diameter range of 100–500 nm were produced stably. The resulting nanofiber nonwoven mat featuring mesopores of about 20.15 nm exhibited excellent thermal stability (the maximum decomposition temperature: 343 °C), exceptional hydrophilicity (15°), and high porosity (67.78 %). This study provides an efficient approach for fabricating high-performance cellulose nanofibers, which hold significant potential for the preparation and application of environmentally friendly, sustainable, and functional cellulose-based materials such as mask filter layers and battery separators.