Fabrication of flexible titania/polyacrylonitrile co-axial nanofibers via electrospinning

Titania/polyacrylonitrile (PAN) co-axial nanofibers were successfully fabricated by the co-axial electrospinning technique to be used as flexible photocatalyst fibers. The introduction of the flexibility to the fibers prevents crumbling of the nanofibers into powder, which is difficult to handle and to be removed from the fluid after uses. The fibers were firstly fabricated into titania(polyvinylpyrrolidone, PVP)/PAN core/sheath fibers. Upon the calcination of the as-synthesized fibers, PVP within the sheath of the fibers was removed, while titania crystalized to photoactive anatase phase. Increasing the calcination temperature resulted in decrease in the fraction of anatase phase within of the sheath fibers and a decrease in the diameter of the PAN core fibers. The optimum calcination temperature is needed to ensure complete removal of PVP, yet PAN remains as the core of the fibers. The tensile tests were applied to ensure that the calcined fibers were still flexible. The photocatalytic activities of the products were also tested and reported.