"Digital Logic for Soft Devices", Preston, D. J., Rothemund, P., Jiang, H. J., Nemitz, M. P., Rawson, J., Suo, Z. and Whitesides, G. M. PNAS Plus, 2019.
doi.org/10.1073/pnas.1820672116

This submersible soft robot autonomously and repeatedly dives and surfaces, enabling applications where continuous underwater sampling is required without hard components--for example, to avoid detection, or to handle delicate samples. The robot can also be summoned to the surface at any time by a human user upon the press of a soft button.