Studies of rheological, electrical, and optical properties of silk fibroin/Benzalkonium chloride modified MMT clay nanocomposite films

Abstract

This paper highlights about the effect of modification of montmorillonite (MMT) clay with Benzalkonium chloride (BAC) on silk fibroin solution and film properties. MMT was modified by cation exchange method using BAC as the cation. BAC modified nanoclay was incorporated in silk fibroin by ultrasonication method for complete dispersive solution to form nanocomposite solution and films. Uniform dispersion of modified nanoclay in silk fibroin films was observed by FESEM-EDX analysis. Rheological studies of pure silk fibroin and nanocomposite solution showed that on adding the modified nanoclay, viscosity of silk fibroin solution decreases however, at higher loading concentration viscosity changes drastically. Dynamic viscoelasticity behavior analysis of nanocomposites showed a decrease in storage and loss modulus on comparison to pure silk fibroin solution. On adding the nanoclay, an increase in the loss factor was observed with an increase in frequency which indicates the dominancy of viscous behavior in nanocomposite solution. Addition of nanoclay in silk fibroin shows a prominent shift in heat flow observed in DSC analysis. Nanoclay induced the opacity in the nanocomposite films as pure silk fibroin films were more transparent. The electrical properties of nanocomposite films observed that at higher concentration of modified nanoclay showed a dynamic increase in the conductivity.