Effect of Aqueous Ethanol Treatment on the Electrospun SF Nanofiber Mats

Bombyx mori silk fibroin nanofiber mats prepared from formic acid solution were treated with aqueous ethanol. The morphology, structural and conformational changes caused by aqueous ethanol were investigated with scanning electron microscope, infrared spectroscopy, X-ray diffraction, and Thermogravimetry/ differential thermal analysis. While the as-spun SF nanofiber mats consisted of α-helix and random coil components, aqueous ethanol treatment of the SF nanofiber mats resulted in significant increase in β-sheet components. This effect was not affected obviously when ethanol concentration changed, but the SF nanofiber distortion was worse and weight loss increased when lower aqueous ethanol was used to treat SF nanofiber mats.