Novel Stimuli-Responsive Turbostratic Oxides/Hydroxides for Material-Driven Robots

Abstract

Herein, a novel class of high-performing actuating oxides/hydroxides with turbostratic crystal structures is reviewed. These materials, including nickel hydroxide/oxyhydroxide, cobalt oxides/hydroxides, nickel-doped cobalt oxides/hydroxides, and manganese oxides, exhibit a volume-changing redox reaction, rendering them an electrochemical actuation behavior. Also, due to their turbostratic crystal structures, they typically exhibit light-driven actuation due to water deintercalation from the crystal structure induced by light. Compared with other actuating materials, these oxides/hydroxides actuate with high stress and strain at fast rates, under very low stimuli requirements. Furthermore, they are easily printable on different substrates, thus allowing flexible robots with demodularized muscle-skeletal designs to be made.