Effects of binary solvent mixtures on the electrospinning behavior of poly (vinyl alcohol)

Different concentrations of PVA solutions were prepared and electrospun from water, ethanol-water and acetic acid-water binary solvent mixtures to study the effects of binary solvent mixtures. The solubility and spinnability of the prepared PVA solutions were discussed using Teas graph. The viscosity of the PVA solutions increased with the increase of PVA concentration. After electrospinning, fibers with an average diameter in the range of 70-300 nm were observed for the fibers spun from acetic acid-water binary solvent mixtures and in the range of 500-1000 nm for the fibers spun from ethanol-water binary solvent mixtures. Circular fibers at lower PVA concentration and flat fibers at higher PVA concentration were observed for the fibers spun from acetic acid-water solutions. Flat fibers were found in case of all the fibers irrespective of PVA concentrations spun from of ethanol-water binary solvent mixtures. Fiber diameters showed an inverse relationship with respect to the electrical conductivity of the solutions, regardless of the solvents. Fiber mats spun from acetic acid-water binary solvent mixtures exhibited nearly double the tensile strength than those of ethanol-water binary solvent mixtures. Differential scanning calorimetry (DSC) analysis of the electrospun fiber mats showed no effect of solvents on thermal properties.