Three Dimensionally Printed Biobased Electrodes: Ionic Liquid and Single-Walled Carbon Nanotube Hybrids in a Vegetable Oil Matrix for Soft Robotics

The field of conductive polymer composites has been growing rapidly in recent years due to the increased demand for cutting-edge applications, such as sensors, soft robots, and other high-tech devices. Despite developing some biobased components, biobased solutions that yield working prototypes are still lacking. Herein, a method for making highly biobased, electroconductive, and 3D printable composites (electrodes) is presented. A formulation composed of acrylate-functionalized rapeseed oil (70 wt %) with the addition of a photoinitiator, reactive monomer, 1-ethyl-3-methylimidazolium acetate (ionic liquid (IL)), and single-walled carbon nanotubes (SWCNT) is reported. The proposed approach eliminates the use of solvents. Combining IL with SWCNTs resulted in highly conductive (up to 38 S m –1 ) biobased electrodes. The in-depth conductivity analysis was done through impedance spectroscopy, 4-point resistivity, and electroconducting atomic force microscopy. The prepared resins enable the creation of complex structures with exceptional precision and accuracy, thoroughly evaluated with optical and scanning electron microscopy. Biobased electrodes created by 3D printing have mechanical qualities like stretchability and flexibility, which make them a suitable replacement for traditional electrodes in soft robotics and flexible sensors. Furthermore, a fully 3D-printed soft-robotic actuator with performance comparable to that of commonly used petroleum-based alternatives was developed.