Grip and release of challenging underwater objects
Because octopus suckers are made of living tissue, they warp, expand and contract to match the job they are approaching. This gives the animal not only a stronger grip, but also a versatility to adapt its hold as it finds objects that are smooth or rough, angular or flat.
With the new octopus-inspired adhesive, research team members can pick up, hold, and release a wide range of challenging underwater objects, including soft and rigid materials that are flat, rough, and even curved.
This capability was demonstrated by constructing an underwater cairn, a carefully constructed pile of underwater rocks. Here, the rocks have various sizes, shapes, and surface roughness and must be picked up but also precisely released to keep the structure balanced. At the same time, they can also grab and release soft, jelly-like beads with ease.
“These types of manipulations are performed by an octopus as they arrange objects around their den,” said Lee. “This demonstration highlights the ability of the octopus-inspired adhesive to precisely manipulate difficult underwater objects.”
The materials also show reliable attachment over multiple cycles and over an extended period of time. In one experiment, the attachment force stayed constant over 100 cycles. In another test, the team held a rough, curved rock for more than seven days underwater, then released it on demand. Particularly in salvage applications where holding an object over an extended period of time, this could be critical.
Gripping like an octopus
Bartlett previously created Octa-Glove, published in Science Advances. Octa-Glove has octopus-inspired adhesives equipped with LIDAR sensors that detected objects nearby, attaching to the object with a strong but gentle bond without applying excessive force. After capture, the suckers can be disengaged on demand, releasing the captured object.
The glove could be a valuable tool for rescue divers, underwater archaeologists, user-assisted technologies, and in health care or other similar work that involves the need to have a firm grip on wet or underwater objects. This recently published research could increase the capacity of the glove, making the grip even stronger.
“We hope to utilize our new adhesive design to further improve Octa-Glove,” said Bartlett said. “Underwater environments present a long list of challenges, and this advance gets us over another hurdle. We’re now closer than ever to replicating the incredible ability of an octopus to grip and manipulate objects with precision, opening up new possibilities for exploration and manipulation of wet or underwater environments.”