Production of nanofibers by electrospinning under pressurized CO2

Electrospinning is one of the simple technical methods for the production 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 work, near-and supercritical CO2 were used as media for this process. At these conditions, the solubility can be tuned by controlling the temperature and pressure. Therefore, it is possible to form particles and fibers within a thermodynamic window where the biopolymer has been softened, but not dissolved. The experiments were conducted by using electrospinning under pressurized CO2 system at pressures of similar to 8.0 MPa and temperature of 313 K to produce several polymers fibers. Polyvinylpyrrolidone was used as the starting material. During the electrospinning process, the applied voltage was 10-17 kV and the distance of nozzle and collector was 8 cm. The concentration of polymer solution was 4 wt%. The morphology-and structure-produced fibers were observed by scanning electron microscopy. The results showed that temperature and pressure affected the morphology of fibers produced by electrospinning in pressurized CO2. This suggests that the thermal behavior of the polymer can be optimized by adjusting the polymer through the adjustment of pressure and temperature by using CO2 as a solvent.