Highly Bendable Ionic Electro-responsive Artificial Muscles Using Microfibrillated Cellulose Fibers Combined with Polyvinyl Alcohol

For promising applications such as soft robotics, flexible haptic monitors, and active biomedical devices, it is important to develop ultralow voltage, highly-performant artificial muscles with high bending strains, rapid response times, and superior actuation endurance. We report a novel highly performant and low-cost artificial muscle based on microfibrillated cellulose (MFC), ionic liquid (IL), and polyvinyl alcohol (PVA), The proposed MFC–IL–PVA actuator exhibits excellent electrochemical performance and actuations characteristics with a high specific capacitance of 225 mF/cm2, a large bending strain of 0.51%, peak displacement up to 7.02 mm at 0.25 V ultra-low voltage, outstanding actuation flexural endurance (99.1% holding rate for 3 h), and a wide frequency band (0.1–5 Hz). These attributes stem mainly from its high specific surface area and porosity, tunable mechanical properties, and the strong ionic interactions of cations and anions with MFC and PVA in ionic liquids. Furthermore, bionic applications such as bionic flytraps, bionic butterflies with vibrating wings, and smart circuit switches have been successfully realized using this technology. These specific bionic applications demonstrate the versatility and potential of the MFC–IL–PVA actuator, highlighting its important role in the fields of bionic engineering, robotics, and smart materials. They open up new possibilities for innovative scientific research and technological applications.