An Anisotropic Hydrogel Actuator Enabling Earthworm‐Like Directed Peristaltic Crawling

Peristaltic crawling, which is the moving mechanism of earthworm‐like limbless creatures in narrow spaces, is a challenging target to mimic by using soft materials. Here we report an unprecedented hydrogel actuator that enables not only a peristaltic crawling motion but also reversing its direction. Our cylindrically processed hydrogel contains gold nanoparticles for photothermal conversion, a thermoresponsive polymer network for switching the electrical permittivity of the gel interior, and cofacially oriented 2D electrolytes (titanate nanosheets; TiNSs) to synchronously change their anisotropic electrostatic repulsion. When a hydrogel, which was designed to include cofacially oriented TiNSs along the cylindrical gel axis, is pointwisely photoirradiated with a visible‐light laser, it spatiotemporally expands immediately (