An adhesive that works properly underwater is almost impossible to create, as there will always be a chance that the structure and objects will not stick. This is because hydrogen bonds, which provide adhesion to the surfaces of objects, are effective only on the surface and not in water. However, marine life exhibits patterns of their own "glue" in aquatic environments: molluscs, which create their own adhesive layer to attach their own bodies to surfaces; octopuses that stick to the desired surface due to suction.
The octopus couples controllable adhesives with intricately embedded sensing, processing, and control to manipulate underwater objects. Current synthetic adhesive–based manipulators are typically manually operated without sensing or control and can be slow to activate and release adhesion, which limits system-level manipulation. Here, we couple switchable, octopus-inspired adhesives with embedded sensing, processing, and control for robust underwater manipulation. Adhesion strength is switched over 450× from the ON to OFF state in <50 ms over many cycles with an actively controlled membrane. Systematic design of adhesive geometry enables adherence to nonideal surfaces with low preload and independent control of adhesive strength and adhesive toughness for strong and reliable attachment and easy release.
Our bio-inspired nervous system detects objects and autonomously triggers the switchable adhesives. Scientists emphasize that this method allows scientists to work as accurately as possible even with fragile objects, since there is no compression and pressure process. The method allows you to work with objects underwater as naturally as possible, without making any effort and eliminating the risk of losing the object from your grasp.