Effect of post-treatment methods and nanoparticles on the conformation of silk fibroin and their impact on electrical properties

This paper investigates the effect of different plasticizers (glycerol and dextrose), post-treatment methods, and metal oxide nanoparticles, i.e. zinc oxide and copper oxide on the structural properties of silk fibroin films and their effect on electrical properties, i.e. dielectric strength. Structural properties of the silk fibroin films have been evaluated using Fourier transform infrared spectroscopy and X-ray diffraction technique. It was found that plasticizers and post-treatment applied on the regenerated silk fibroin films have impacted the beta-sheet conformation significantly. The dielectric strength of the silk fibroin films was measured using the parallel plate capacitor method and an interrelation with structural properties was observed. Nanoparticles have been introduced into the silk fibroin films as a progressive method to impart substantial effect on the dielectric strength of the silk fibroin films. However, an unexpected change in dielectric strength has been obtained. The mechanism behind the change in dielectric strength has been explored in this work.