Effects of Rotating Drum and Polymer Concentration on Morphology of Electrospun TiO2/PVP Nanofibers

Abstract     In this research work, electrospun TiO2/PVP nanofibers were prepared by using two different collectors, i.e., flat stationary plate and rotating drum. The effects of these collectors in conjunction with polymer concentration in TIP/PVP sol solutions (i.e., 3, 5, and 7 wt. %) were investigated on morphologies of the as-spun TiO2/PVP composite nanofibers. SEM micrographs were used for determination of the average  nanofiber diameters and their standard deviations (SDs). Rotating speed of the collecting drum was set at 500 rpm for all samples prepared by it, while other electrospinning parameters (i.e., applied voltage, flow rate, tip-to-collector distance, and needle gage) were the same for the counterpart samples prepared from each of sol solutions by two types of collectors, throughout the experiment. It was observed that TiO2/PVP nanofibers electrospun by rotating drum have average diameters and SD of 144 ± 58 nm (from sol solution with 3 wt. % PVP at applied voltage of 10 kV) and 122 ± 71 nm (from sol solution with 5 wt. % PVP at applied voltage of 15 kV). These magnitudes were pretty much lower than the average diameters of TiO2/PVP nanofiber prepared by a flat stationary plate. The average diameters of TiO2/PVP nanofiber prepared by flat stationary plate and rotating drum were 258 ± 122 and 292 ± 135 nm, respectively when polymer concentration in TIP/PVP sol solution increased to 7 wt. %. It is clearly shown that by increasing polymer concentration in electrospinning solution, the average diameter of the electrospun TiO2/PVP nanofibers increased, afterward. Therefore, rotational speed of collecting drum should be increased rationally if there is a need for preparation of finer electrospun nanofibers.