A dry process for polymer nano-microfibers prepared by Electrospinning under pressurized CO ₂

Electrospinning is known as an efficient technique for the fabrication of polymer nanoparticles and nanofibers. Various polymers have been successfully electrospun into ultrafine particles and fibers in recent years, mostly in solvent solution and some in melt form. In this study, electrospinning was conducted under pressurized carbon dioxide (CO ₂) to reduce the viscosity of polymer solution. The experiments were conducted at 313 K and ∼8:0 MPa. Poly(vinyl pyrrolidone) (PVP) in dichloromethane (DCM) was used as a polymer solution with 4wt% of concentration. The applied voltage was 17 kV and the distance of nozzle and collector was 8 cm. The morphology and structure of the fibers produced were observed using scanning electron microscopy (SEM). Under pressurized CO ₂, PVP electrospun was produced without bead formation with diameter ranges of 608.50-7943.19 nm. These behaviors hold the potential to considerably improve devolatilization electrospinning processes.