Improvement of the electrospinnability of Polyvinyl alcohol via dialysis and complexation pretreatment

The electrospinnability of polyvinyl alcohol (PVA) aqueous solutions for two samples (HS and FL) was carried out. FL solutions produced nanofibers in electrospinning process, whereas HS solutions showed poorer electrospinnability accompanying dropping and electro-spraying. The analysis of the spinning solution properties indicated that the electric conductivity and viscosity of both FL and HS solutions demonstrated similar behaviors, however, the surface tensions of FL solutions were slightly decreased while the surface tension presented U-shaped curves for HS solutions with the increase of polymer concentration. The NMR spetra and DSC results implied that HS had higher degree of saponification. The metal element analysis results meant that HS contained high concentrations of calcium and aluminum ions while FL much less. The dosage of calcium chloride into FL aqueous solutions indicated that electrospinnability was significantly aggravated. The electrospinnability of HS was substantially improved both by dialysis and complexation. It was the high degree of saponification and it was intramolecular crosslinking and intermolecular crosslinking occurred between PVA chain and the metal ions that coined the abnormal behaviors in surface tension and thus deteriorated electrospinnability.