The Effect of Organic/Inorganic Hybridization on the Structures of Nanofibers

Polyvinyl acetate (PVAc) and PVAc/titanium dioxide (TiO ₂ ) nanofiber mats were prepared by electrospinning process. In this study, three types of solution were used. The first was PVAc dissolved in only acetone, the second was prepared by adding TiO ₂ sol into PVAc—acetone solution in sol—gel method, the third was prepared by adding ethanol into PVAc—acetone solution. The effect of solution properties such as viscosity, surface tension, and electrical conductivity on the formation and morphology of electrospun fibers was investigated. Pure PVAc had a beads-on-string structure, but the beads almost disappeared when the TiO ₂ was added. Electrospun fibers had average diameters of 529, 596, 333, 303 nm for PVA/TiO ₂ volume ratios of 100 : 0, 100 : 10, 100 : 20, and 100 : 30, respectively. Since the added TiO ₂ precursor dispersed in ethanol solvent was in the ratio of 1 : 30, it was necessary to prepare the solution with same ratio of ethanol for contrast (ethanol is a nonsolvent of PVAc). As the concentration of ethanol increased, the average diameter of nanofibers decreased and change in the bead shape from spindle-like to spherical was observed on the whole.