Abstract
On the formation of spherulites in silk fibroin gel obtained from fresh silk gland, the conditions for crystallization such as pH and temperature and the structure of the spherulites resulted under these conditions were examined.
1. Spherulites of silk fibroin were observed at temperatures lower than 50°C and the range of pH from 3.0 to 10 except in pH 5.0. This prohibition of spherulites formation at pH 5.0 may be consistent with the fact the pH is about 5.0 in the living silk gland where the crystallization is not permissible.
2. Silk fibroin spherulites is confirmed to be α-form structure by X-ray diffractometry.
Surface structure of spherulites is similar to that of many other linear polymers under electron microscope.
The needle crystals which are often found in silk fibroin film coincide with β-form structure of silk fibroin.
