Micro-structure porous electrolytes for highly responsive ionic soft actuators and artificial muscles

Abstract

Ionic soft actuators, are new type of actuator that bend due to the ion migration in a polymer electrolyte membrane under the electrical field generated by two sandwiching electrodes. This type of soft actuators have gained increasing attention because they have successfully been applied in many biomimetic soft robotics. However, further explorations require to enhance their performance, which, in turn, demands for strong and flexible polymer electrolytes with continuous conducting phases facilitating ion movement. Here, we report a simple technique to generate continuous conducting channels in polymer electrolytes by penetrating ionic liquid into the poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) porous micronetwork. While the PVDF-co-HFP skeleton provided mechanical strength and flexibility for the electrolyte membrane, the free movement of ionic liquids in the porous micronetwork enhanced actuation performance. Therefore, the as-prepared actuators showed better performance in comparison with those made of conventional PVDF-co-HFP electrolyte membranes such as a large tip displacement of 25 mm at 0.5 V, fast rise time of 2.5 s without back relaxation, good stability remaining 95 % of the original performance after 20,000 actuation cycles. This high performance enabled us to realize some complex deformation especially in the field of Ionic Soft Artificial Muscles.