Preparation of Water-Insoluble Silk Fibroin Films. Study of Their Structure and Properties

Conditions for obtaining water-insoluble silk fibroin in the form of films have been worked out. Using optical microscopy, a change in the surface morphology of the films was demonstrated due to a structural transition to a coarsely fragmented state as a result of the treatment of the films with methyl alcohol. The conformational transition of silk fibroin from the disordered structure of the untreated film to the β-folded structure was confirmed by the FTIR spectroscopy method. The glass-transition temperature of the native film equal to 216°C was determined by the method of differential scanning calorimetry. A study of the mechanical properties of silk fibroin films in a liquid medium showed that their strength decreases and elasticity increases by almost 15 times compared with tests of the same films in a dry state.