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, Hermetia illucens). 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-1H-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.