Electroconductive Bionanocomposites from Black Soldier Fly Proteins for Green Flexible Electronics

Printed and flexible electronics hold the potential to revolutionize the world of electronic devices. A primary focus today is their circularity, which can be achieved by using biobased materials. In this study, electrically conductive bionanocomposite materials suitable for flexible electronics were fabricated using proteins from the black soldier fly (BSF, <i>Hermetia illucens</i>). The valorization of BSF biomacromolecules is currently being pursued in the framework of emerging circular economy models for the bioconversion of the Organic Fraction of Municipal Solid Waste (OFMSW), where BSF has been demonstrated to act as an extremely efficient bioconverter to provide lipids, chitin, and proteins. Here, the BSF protein extracts were characterized by proteomic techniques, revealing a pool of myofibrillar proteins able to interact through intermolecular β-sheet interactions. Flexible and electroconductive bionanocomposite materials were next formulated by combining BSF proteins with a conductive carbon black (CCB), either in its pristine form or functionalized with 2-(2,5-dimethyl-1<i>H</i>-pyrrol-1-yl)-1,3-propanediol (serinol pyrrole, SP), using water as the only solvent and incorporating glycerol and carboxymethylcellulose (CMC) as additional green ingredients. A sustainable, low-pressure cold plasma (LPCP) technology was ultimately proposed to achieve high film surface hydrophobicity. Characterized by effective biodegradability, strain-sensing properties, high electrical conductivity (up to 0.9 × 10^-2 S/cm at a filler content of 8% v/v (15% w/w)), and high surface hydrophobicity, the bionanocomposites presented here may be well suited for disposable flexible electronics, as in wearable devices, electrostatic discharge fabrics, or packaging, hence offering new routes toward OFMSW valorization and the development of green flexible electronics.