Direct electrospinning of ultrafine titania fibres in the absence of polymer additives and formation of pure anatase titania fibres at low temperature

Without polymer additives, ultrafine titania fibres were successfully prepared via the electrospinning technique in combination with the sol-gel process. The viscosity of titania precursor sol for electrospinning was controlled by the evaporation of solvent and contact with moisture in air. The morphology of the electrospun titania fibres was characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD) and transmission electron microscopy (TEM). The surface morphology and crystallinity of titania fibres were dependent on the calcination temperature. In particular, the titania fibres showed pure anatase crystalline structure when they were calcined at temperature as low as 250 degrees C for 3 h. Also, the titania fibres calcined at 1300 degrees C for 3 h showed rutile crystalline structure and burl-like wavy surfaces. This wavy surface seemed to be formed by aggregation of crystalline titania particles, which favours the round shape to minimize the surface area.