Bacterial cellulose as a substrate for sustainable inkjet-printed electronic devices

The diffusion of sensing systems into everyday life can greatly improve the quality of life. Consider the benefits of employing sensing systems in the biomedical area to monitor vital parameters (blood pressure, heart rate), or in the agricultural field to monitor overall field health and schedule irrigation and harvest times. Nevertheless, most of the currently available electronic devices are manufactured by adopting non-sustainable materials and production methods. Considering the current climate crisis, it is necessary to promote environmentally sustainable production of electronic devices using sustainable, solvent-free and eco-friendly materials. Bacterial Cellulose (BC) is a natural biopolymer produced by Gram-negative bacteria, such as Acetobacter xylium and Gluconacetobacter hanseni. BC is biocompatible, biodegradable, renewable, flexible and has a fibrous structure. These unique properties allow BC to be used as a substrate to produce sustainable electronic systems. In the present work, BC was employed as a substrate for the fabrication of circuit components, including inductors and resistors. These components were produced using inkjet printing technology with silver conductive ink. The fibrous nature of the BC material gives it a relatively high surface roughness, which can compromise the characteristics of the printed components. To improve the planarity of the BC, a natural green biopolymer, chitosan, was applied. This process modifies the surface characteristics of BC by enhancing the printing resolution. Properties of components printed on BC were compared to those produced, under identical printing conditions, on flexible substrates commonly used in electronics, such as poly(ethylene naphthalene) (PEN).