Green Electrospinning of Biodegradable Cellulose Acetate Nanofibrous Membranes with Tunable Porosity

The electrospinning of polymer nanofibers has received significant attention owing to their high surface-area-to-volume ratio, high porosity, adjustable pore size and texture, and highly interconnected porous structure. In particular, the electrospinning of biodegradable cellulose acetate (CA) nanofibers has sparked interest in diverse applications, including drug delivery systems, scaffolding for tissue engineering, air filtration, and affinity membrane systems. However, the electrospinning process has been mostly performed using toxic and hazardous solvents and additives. We developed electrospun CA nanofibers using a green solvent system comprising dimethyl carbonate and cyclopentanone. The use of green additives, namely, tetrabutylammonium bromide salts and sophorolipid-based biosurfactants, obtained from honey yeast, substantially improved the spinnability of the CA solution. Moreover, the nanofiber diameter and porous texture were tunable by adjusting the solvent ratio. Pore generation was induced using volatile dimethyl carbonate, which quickly evaporated from the fiber jet. Molecular dynamics simulations demonstrated that the electrospinning process can be divided into three stages. The addition of the biosurfactant facilitated the evaporation process and improved the uniformity of the nanofibers. Furthermore, the nanofibers can be degraded using esterase and cellulase enzymes. To summarize, the electrospinning of ultrafine CA porous nanofibers with tunable morphology was achieved using green solvents and additives.