Novel Self-Oscillating Polymer Actuators for Soft Robot

Influence of Belousov–Zhabotinsky Substrate Concentrations on Autonomous Oscillation of Polymer Chains with Fe(bpy)3Catalyst

“…If we can construct autonomous systems like living organisms using custom designs, unique spontaneous polymer systems can be developed. Recently, self-oscillating polymers and gels have been developed for use in soft actuators and soft robots. − For such applications, either the Belousov–Zhabotinsky (BZ) reaction or the Landolt pH-oscillator have been utilized as a chemical energy source for the autonomous polymer systems. − In this study, we adopted the BZ reaction because it does not need the external pump system, an essential component of the pH oscillation reaction used to ensure flow of the substrate solution. In the BZ reaction, self-oscillating redox reactions of the metal catalyst occur; also, target or spiral patterns are observed in an unstirred condition, while a periodic change in the color of the entire solution occurs in the stirred condition. − The overall BZ reaction involves the oxidation of malonic acid (MA), an organic acid, by sodium bromate (NaBrO 3 ), used as an oxidant, in an aqueous solution containing nitric acid (HNO 3 ) and the Fe catalyst moiety covalently bonded to the polymer chain.…”