Silk Fibroin Nanocomposites with Indium Tin Oxide toward Sustainable Capacitive Touch Sensing Applications

The development of multifunctional sustainable polymer composites is an increasing need in the scope of the Internet of Things (IOT) and the circular economy paradigm. In this context, nanocomposites based on silk fibroin (SF) and indium tin oxide (ITO) (up to 40 wt %) were produced by solvent casting to improve the mechanical and dielectric properties of the protein, and develop capacitive touch sensing devices. Samples with good filler dispersion, compact morphology, and optical transparency were obtained independently of the filler content. The structural conformation of ITO/SF nanocomposites and mechanical and dielectric properties are dependent on ITO content, with the dielectric constant reaching values of up to 10 for an ITO content of 40 wt %. On the other hand, the thermal transitions of samples are independent of the filler amount. ITO/SF nanocomposites with 10 wt % ITO content were used for capacitive touch sensor development. The excellent sensing behavior and reproducibility of the device demonstrate the suitability of the developed silk fibroin-based nanocomposites for sustainable electronic approaches.