Electrical response and biodegradation of Sepia melanin-shellac films printed on paper

Sepia melanin, a biopigment extracted from the ink sac of cuttlefish, is relevant to sustainable organic electronics. In this work, we flexographically print films from an ink of Sepia melanin including shellac as a bio-sourced binder on silver electrode-patterned paper. We examine the electrical response in high humidity and ambient conditions (here the electronic conductivity is as high as 10−4 S/cm). Additionally, we study the biodegradation of the printed films and their individual constituents based on their mineralization into CO2 under composting conditions. The printed films exhibit biodegradation levels of about 97 ± 25% in 85 d. We observe microorganism colonization on the printed film’s surface. The analysis of the microbial community on the compost reveals that bacterial species within the Acidimicrobiia class, specifically Actinomarinales order, are potentially responsible for the biodegradation of the printed film. Meanwhile, ecotoxicity tests conducted by germinating Lolium multiflorum and Tagetes erecta suggest that printed films have negligible phytotoxicity. Sepia melanin, a biopigment extracted from cuttlefish ink, shows promise for sustainable organic electronics. Here, printed films including Sepia melanin and shellac are studied for their compostability and electrical behavior, showing electrical conductivities of about 10−4 S/cm and biodegradability.