Fig. 5.

Underwater walking, crawling, and jumping locomotion modes. (A) Self-sustained wave-like deformation for propulsion by shining a stationary beam of a 532-nm laser to a cantilever construct from LCG-50 (21 × 3 × 0.1 mm³); the cantilever is fixed to a frame with the length of 16 mm. In this design, the continuous displacement of the wave leads to a change in the position of the exposed and unexposed areas to a stationary beam (i–iv). (B) Crawling of the sample through undulatory traveling waves created by scanning 532-nm laser (input power ∼ 0.4 W). Note that the altered mode of illumination in our design leads to different transient geometries in the state iv of wave formation in A and B. (C) Walking of an LCG-50 cantilever (21 × 3 × 0.1 mm³) on a ratchet surface; the light is shone from a high-pressure mercury vapor short-arc lamp with an intensity of almost 1.5 W⋅cm⁻². (D) Jumping of an LCG-70 cantilever (21 × 3 × 0.1 mm³) on a ratchet surface; the light is shone from the same source in C but with an intensity of 1.2 W⋅cm⁻². The left side in all figures shows predictions obtained from finite-element simulations. All inset figures show the thermal strain profile through the thickness of an arbitrary spot on corresponding cantilevers. The maximum temperature is 60 °C. All experiments were performed in water at room temperature (23 °C). h, homeotropic; p, planar. (All scale bars, 4 mm.)