High-strength and recyclable pure chitosan films manufactured by an ionic liquid assisted roll-forming method

Chitosan materials perform a great potential for applications in sustainable and flexible electronics, owing to their abundance, biocompatibility, and biodegradability. While limited by the inherent shortcoming of having a melting temperature higher than its degradation temperature, chitosan is hard to be manufactured by traditional thermoforming or solvent-free methods. Herein, we demonstrated a tractable roll-forming method to process chitosan films under the plasticizing effect of ionic liquids. In particular, the additional ionic liquids could be removed by Soxhlet extraction and then recycled toward sustainability. The final regenerated chitosan films exhibited outstanding strength (53.1 MPa), high elongation (3.5%) and hardness (0.4 GPa). Simultaneously, the successful fabrication of interdigital electrode sensors on the chitosan film indicated the feasibility of manufacturing flexible electronics using chitosan substrates. Thus, our innovative strategy enables the sustainable formation of high-performance chitosan films, offering a broader prospect for the new generation of chitosan-based biodegradable electronics.