Octopus-inspired technology successfully maneuvers underwater objects

Having the ability to grab and release these underwater objects such as heavy rocks, small shells, soft beads and other debris can be a powerful tool for underwater rescue and even rescue operations. Their findings were published in Advanced Science.

This work was performed with Virginia Tech graduate researchers Austin Via, Aldo Heredia, and Daniel Adjei. Graduate research assistant Chanhong Lee was first author on the paper, reporting research supported by the National Science Foundation through the Designing Materials to Revolutionize and Engineer our Future program.

“I’m fascinated by how an octopus can one moment hold something tightly and then instantly release it. It does this underwater, on objects that are rough, curved and irregular – that’s quite an achievement,” said Bartlett .

Controlling yourself underwater

To overcome this long-standing challenge, Bartlett and his team looked at the shape of the octopus. Specifically, they looked at the external structure of the octopus’s sucker, called the infundibulum. This inspired researchers to create an adhesive that uses an elastic, curved rod with an active, deformable membrane that changes shape for adhesion to multiple surfaces.

The curved rod binds to large-scale curvatures while increasing adaptability to small-scale roughness. These mechanisms work synergistically to improve adhesion across multiple length scales.

This resulted in octopus-inspired adhesives that are 1,000 times stronger when activated compared to the easy-release state. It is important to highlight that this change occurs in a fraction of a second, around 30 milliseconds. Octopus-inspired adhesives now achieve high bonding strength on a variety of surfaces, including rough, curved and irregular objects, as well as in different fluids. With this new tool, a diver could grip a slippery object without over-tightening, while also being able to grab it quickly with quick shifts.

Grab and release challenging underwater objects

Because octopus suckers are made of living tissue, they deform, expand and contract to suit the job they are doing. This gives the animal not only a stronger grip, but also the versatility to adapt its grip as it encounters smooth or rough, angular or flat objects.

With the new octopus-inspired adhesive, research team members can pick up, hold and release a wide variety of challenging underwater objects, including soft and rigid materials that are flat, rough and even curved.

This ability was demonstrated through the construction of an underwater cairn, a carefully constructed pile of underwater rocks. Here, the rocks have various sizes, shapes and surface roughness and must be collected but also released with precision 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 it arranges objects in its burrow,” said Lee. “This demonstration highlights the octopus-inspired adhesive’s ability to precisely manipulate difficult underwater objects.”

The materials also exhibit reliable hold over multiple cycles and over a long period of time. In one experiment, the clamping force remained constant over 100 cycles. In another test, the team held a rough, curved rock underwater for more than seven days and then released it when asked. Particularly in salvage applications where holding an object for a long period of time, this can be critical.

Grabbing like an octopus

Bartlett previously created Octa-Glove, published in Science Advances. Octa-Glove features octopus-inspired stickers equipped with LIDAR sensors that detect nearby objects, attaching to the object with a strong but gentle bond without applying excessive force. After capture, the suction cups can be disengaged on demand, releasing the captured object.

The glove can be a valuable tool for rescue divers, underwater archaeologists, user-assisted technologies and in healthcare or other similar work that involves the need to firmly grip wet or underwater objects. This recently published research could increase the glove’s capacity, making the grip even stronger.

“We hope to use our new adhesive design to further improve the Octa-Glove,” said Bartlett. “Underwater environments present a long list of challenges, and this advancement leads us to overcome another obstacle. We are now closer than ever to replicating an octopus’ incredible ability to precisely grasp and manipulate objects, opening up new possibilities for exploration and manipulation. of humid or underwater environments.”