3D printed mechanical robust cellulose derived liquid-free ionic conductive elastomer for multifunctional electronic devices.

Ionic gel-based wearable electronic devices with robust sensing performance have gained extensive attention. However, the development of mechanical robustness, high conductivity, and customizable bio-based ionic gel for multifunctional wearable sensors still is a challenge. Herein, we first report the preparation of 3D printed cellulose derived ionic conductive elastomers (ICEs) with high mechanical toughness, high conductivity, and excellent environment stability through one-step photo-polymerization of polymerizable deep eutectic solvents. In the ICEs, carboxylate cellulose nanocrystals (C-CNCs) were used as a bio-template for the in-situ polymerization of the aniline to avoid the aggregation of polyaniline and yield a high conductivity (58.7 mS/m). More importantly, the well-defined structural design combining multiple hydrogen bonds with strong coordination bonds endows the ICEs with extremely high mechanical strength (4.4 MPa), toughness (13.33 MJ*m), high elasticity and excellent environment stability. Given by these features, the ICE was utilized to assemble multifunctional strain, humidity, and temperature sensors for real-time and reliable detection the human motions, respiration, and body temperature. This work provides a promising strategy for designing the new generation of strong, tough bio-based ionic gel for multifunctional wearable electronic devices.