(133f) Flexible Cellulose Films for Transient Soft Electronic Devices

The significant increase in electronic waste, driven by the use of non-biodegradable substrates in electronic devices, necessitates sustainable alternatives. Cellulose, the most abundant biopolymer on Earth, offers a promising solution for certain applications. However, it is challenging to solubilize cellulose and ensure that the corresponding film has the correct mechanical properties without compromising biodegradability. Here, we dissolved and regenerated microcrystalline cellulose into films by utilizing an N,N-dimethylacetamide / lithium chloride co-solvent system. To improve flexibility and mechanical integrity, glycerol was used as a plasticizer and poly(ethylene glycol) diglycidyl ether (PEGDE) as a cross-linker agent. Characterization techniques (tensile test, FT-IR, XRD, UV-Vis, XPS, TGA, SEM) were used to assess film properties. The electronic applicability of cellulose films was evaluated using screen-printed silver nanowires in electro-mechanical testing. Incorporating glycerol significantly reduced Young's Modulus and increased strain-to-break, while cross-linking with PEGDE improved toughness without sacrificing tensile strength. Printed films maintained excellent conductivity under mechanical stress. Enzymatic hydrolysis enabled effective silver recovery, and underscored the films' biodegradability and recycling potential. This work introduces a viable, bio-based alternative for transient electronic device substrates, addressing environmental concerns associated with electronic waste. The use of plasticizers and cross-linkers to enhance cellulose performance not only offers a sustainable pathway for the electronics industry but also showcases the potential of biopolymers in high-tech applications, paving the way for greener electronic devices.