PHYSICAL-PROPERTIES AND STRUCTURE OF SILK .6. CONFORMATIONAL-CHANGES IN SILK FIBROIN INDUCED BY IMMERSION IN WATER AT 2-DEGREES-C TO 130-DEGREES-C

In the reported experiments, silk fibroin films in the random-coil and beta -form conformations were immersed in water at temperatures from 2 to 130 degree C, and conformational changes were followed by x-ray diffraction, infrared spectroscopy and differential scanning calorimetry. On treatment with water below 60 degree C, the random-coil conformation is converted to the alpha form and above 70 degree C to mixtures of the alpha and beta conformations. The beta -form content increases as the immersion temperature is raised. The beta form is not affected by immersion in water in the temperature range studied.