Design of self-oscillating gel actuators for aiming at chemical robot

Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators and artificial muscles. In particular, electroactive polymers that change shape when stimulated electrically are promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli, for example the self-beating heart muscle. Here we show novel bending-stretching, self-walking and peristaltic motion of polymer gel actuators without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of an oscillating reaction, i.e., the Belouzov-Zhabotinsky (BZ reaction occuring inside the gel. Although the gel is a synthetic polymer, it shows autonomous motion as if it is alive.