A casein-based biodegradable and sustainable capacitive sensor
Elena De Gregorio, Filippo Manfredi Miliani, Federico Maria Vivaldi, Nicola Calisi, Noemi Poma, Arianna Tavanti, Celia Duce, Federica Nardella, Stefano Legnaioli, Angela Gilda Carota, Lucanos Marsilio Strambini, Denise Biagini, Tommaso Lomonaco, Fabio Di Francesco, Pietro Salvo
Abstract
The production of electrical and electronic equipment is increasing worldwide with a dramatic increase of electronic waste. Sustainable materials to produce sensors may thus positively impact on the environment. Casein is a milk protein that was used to fabricate a non-cytotoxic and biodegradable capacitive sensor by a green chemical process adding glycerol and trehalose. The casein-based film was characterized by means of thermal (TGA and EGA-MS) and spectroscopic (FTIR-ATR and Dielectric Spectroscopy) techniques. Contact angle, water vapour transmission rate, cytotoxicity and biodegradability were also assessed. A PEDOT:PSS/reduced graphene oxide ink was produced and screen-printed onto the film surface to obtain electrically conductive electrodes. The dielectric properties of the casein-based film allowed for the fabrication of a capacitive sensor that proved sensitive to pH changes.