2, Pohang University of Science and Technology (POSTECH), Pohang, , Korea (the Republic of)
Soft actuators that can show mechanical deformation under various external stimuli have extensively been studied to exploit soft robotics with precise control over their motions. The key challenges for the development of practically useful soft actuators lie in large strain, high mechanical strength, durable actuation motion, and low power consumption. Polymer actuators based on ionic polymers that can be operating under a few volts have been considered as the most promising candidate for such actuators; however, the motion of such actuators is limited to “bending motion”, committed in the early stages of technologies. Herein, we report a new strategy for the development of high-performance ionic polymer actuators with various actuation motions. We employed ionic liquid-containing block copolymers having high ionic conductivity and stretchable properties. Various geometric changes of the actuators beyond typical trilaminar shape were attempted, based on comprehensive understanding of electric field distribution in the polymer layers. The resultant actuators showed great promises towards diverse actuation motions such as helical, lateral expansion/shrinkage, and self-closing behavior. Given that our actuators can be operatable only under 3 volts, it can be applicable to various biomimetic devices.