Structural and conformational changes of regeneratedAntheraea pernyi silk fibroin films treated with methanol solution

Abstract

The regenerated Antheraea pernyi silk fibroin films were prepared from calcium nitrate solution and crystallized with aqueous methanol solution. The structural and conformational changes were investigated by the X-ray diffraction method and infrared spectroscopy upon methanol treatment. The concentration and treatment time of aqueous methanol solution have a great influence on the conformation of regenerated films. The conformational change from a random coil to β-sheet structure was occurred within 5 min by the treatment of 40–60% methanol solution. As the methanol concentration increases up to 100%, the transition time of conformational change is delayed, and the structural change is not occurred in the case of 100% methanol used. The content of a α-helix, β-sheet, and random coil conformation was calculated and examined to find out the effect of methanol treatment on the conformation changes. The β-sheet structure can be transformed from a random coil, while the content of α-helix structure is not changed, regardless of methanol treatment. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2887–2894, 1999