Fig. 6.
SEM images of the prepared PVP fibers under different working temperatures. a F5, ambient temperature (20 °C), b F6, 30 °C, c F7, 40 °C, and d F8, 50 °C. Their upper-right insets show enlarged images of the corresponding PVP nanofibers
SEM images of the prepared PVP fibers under different working temperatures. a F5, ambient temperature (20 °C), b F6, 30 °C, c F7, 40 °C, and d F8, 50 °C. Their upper-right insets show enlarged images of the corresponding PVP nanofibers