Effect of ZnO Nanoparticles on the Electrospinning of Poly(vinyl alcohol) From Aqueous Solution: Influence of Particle Size

Recently, interest in nonwoven mats composed of fibers manufactured by drawing polymer solutions or melts with suspended nanoparticles has been growing due to exciting opportunities for use in biomedical applications. Poly(vinyl alcohol) (PVA), due to its bio-compatibility, and zinc oxide (ZnO), due its antibacterial activity, present one interesting combination for the manufacture of nonwoven fiber mats for potential use as wound dressings. Therefore, we have investigated the electrospinning of aqueous PVA solutions with suspended ZnO nanoparticles. ZnO nanoparticles of three different diameters (20, 70, and 100 nm) were used in the study. Interestingly, we found that increasing the diameter of suspended ZnO nanoparticles was accompanied by a decrease in the diameter of the electrospun fibers. Fourier transform infrared spectroscopy indicated that the ZnO nanoparticles were merely suspended in the aqueous PVA solution without any chemical bonding between the ZnO nanoparticles and the PVA chains. Shear rheometry of the suspensions indicated that, over the relevant range of shear rates, all of the samples exhibited essentially Newtonian behavior. However, the viscosity increased with a decrease in the diameter of the ZnO nanoparticles. We suggest that the effect of the nanoparticles on the diameter of the electrospun fibers is through their effect on the viscosity of the suspension from which the fibers are drawn. Finally, as was expected, increasing the electric field strength led to a gradual decrease in the diameter of the electrospun fibers. (C) 2013 Society of Plastics Engineers