Alumina nanofiber synthesis by combined sol-gel and electrospinning techniques

Abstract

The combination of sol-gel and electrospinning techniques was used to produce alumina nanofibers. Aluminum isopropoxide (AIP) was used as an alumina source and Polyvinyl alcohol (PVA) was used as a spinning aid. For the preparation of the spinning solution, AIP was first hydrolyzed with water. The solution was further stirred for desired period of aging time. Then, PVA was added after the mixture became slurry to control solution viscosity. The homogenous solution thus prepared was used for electrospinning. The as-obtained electrospun fibers were in boehmite/PVA composite that could be converted into -alumina via calcination at 1,20oC. The results show that the crystallite size of the electrospinning products is smaller than the products in powder form because the morphology as the nanofiber control in crystal growth into one dimension. Viscosity of the spinning solution was found to be an important factor affecting uniformity of the obtained fibers. The viscosity of the spinning solution changes strikingly within a short period of time from 24 to 48 hrs. In addition, it was found that the phase transformation of alumina within the products is greatly influenced by the amount of acid added into the spinning solution. The effect of the acid is more pronounced for the product in fiber form.