Electrospinning Silica/Polyvinylpyrrolidone Composite Nanofibers

Small diameter nanofibers of silica and silica/polymer are produced by electrospinning silica/polyvinylpyrrolidone (SiO2/PVP) mixtures composed of silica nanoparticles dispersed in polyvinylpyrrolidone solutions. By controlling various parameters, 380+/-100 nm diameter composite nanofibers were obtained with a high silica concentration (57.14%). When the polymer concentration was low, beads-on-a-string morphology resulted. Nanofiber morphology was affected by applied voltage and relative humidity. Tip-to-collector distance did not affect the nanofiber diameter or morphology, but it did affect the area and thickness of the mat. Heat treatment of the composite nanofibers at 200 degrees C crosslinked the polymer yielding solvent-resistant composite nanofibers, while heating at 465 degrees C calcined and selectively removed the polymer from the composite. Crosslinking did not change the nanofiber diameter, while calcined nanofibers decreased in diameter (300+/-90 nm) and increased in surface area to volume ratio. Nanofibers were characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). (C) 2014 Wiley Periodicals, Inc.