Chemomechanical origin of directed gel locomotions driven by intenal chemical pulses*

Our previous work reported the directed locomotion of self-oscillating polymer gels in asymmetric environments, such as retrograde and direct wave locomotion, reciprocal migration, photophobic and phototropic movement. We now ask whether directed locomotions and their transitions can be generated only from intrinsic chemical dynamics and its modulation. We examine this question by simulating the locomotion of a responsive polymer gel in a homogeneous environment. We find that autonomous directional locomotion emerges in the absence of asymmetric interaction with the environment, and that a transition between modes of gel locomotion can be induced by adjusting the spatially uniform intensity of illumination or certain kinetic and mechanical system parameters. We find that the internal wave dynamics and modulation of the system act as the impetus for signal-driven active locomotion in a manner similar to the way in which an animal's locomotion is generated via driving by nerve pulses.