Direct fabrication of composite and ceramic hollow nanofibers by electrospinning

Hollow nanofibers with walls made of inorganic/polymer composites or ceramics have been prepared by electrospinning two immiscible liquids through a coaxial, two-capillary spinneret, followed by selective removal of the cores. The capability and feasibility of this technique have been demonstrated by the fabrication of titania/polymer or anatase nanotubes whose size and wall thickness could be independently varied by controlling a set of experimental parameters. The presence of a sol-gel precursor in the sheath liquid was necessary for the formation of stable, coaxial jets and hollow fibers with robust walls. The circular cross-section, uniform size, and well-control led orientation of these long hollow nanofibers are particularly attractive for use in fabricating fluidic devices and optical waveguides.