Fig. 4: On-demand reversible underwater adhesion triggered by electricity.

a Selected snapshot images showing the fast and on-demand pick-up and release of 200 × g metal load under a DC voltage of 20 V. Here, the scale bar is 2 cm. b The response time of reversible underwater adhesion is regulated by the applied voltage. The error bars are the standard deviations of five measurements. c The schematic diagram of the experimental setup to visualize the electrolysis process inside the water bridge. d Selected snapshots showing the generation and movement of bubbles during the electrolysis of water in the water bridge. Scale bar: 2 mm.