Scientists are drawing inspiration from nature to develop innovative technologies. A recent team effort has led to the creation of an adhesive modeled after octopus suckers, enabling quick gripping and controlled release of various underwater items. This capability could become a crucial asset for underwater retrieval and rescue operations.
At Virginia Tech, a research team, under the guidance of Associate Professor Michael Bartlett, has developed an octopus-inspired adhesive based on the unique structure of octopus suckers, designed to swiftly grasp and release difficult underwater objects.
This adhesive is capable of securely holding items such as heavy stones, small shells, soft beads, and various other debris, making it an invaluable tool for underwater salvage and rescue missions. Their research has been published in Advanced Science.
The project involved undergraduate researchers Austin Via, Aldo Heredia, and Daniel Adjei, with Graduate Research Assistant Chanhong Lee as the main author. The study received support from the National Science Foundation through its Designing Materials to Revolutionize and Engineer our Future program.
“I’m intrigued by how an octopus can firmly grasp an object one moment and let it go instantly the next, even while submerged, on surfaces that are rough, curved, and irregular—that’s a remarkable capability,” Bartlett remarked.
Adapting the Grip for Underwater Use
To tackle this complex challenge, Bartlett and his team examined the form of an octopus. They specifically focused on the outer structure of the octopus’s sucker, known as the infundibulum. This gave rise to an adhesive that employs an elastic, curved stalk paired with a dynamic, flexible membrane that adapts to different surfaces.
The curved stalk effectively adheres to large curvatures while improving adaptability to intricate surface textures. These components work together to enhance adhesion across various scales.
This led to the development of adhesives inspired by octopuses that are 1,000 times stronger when activated compared to their initial easy-release configuration. Notably, this transition occurs in just 30 milliseconds. The adhesives are now capable of achieving robust attachment on a wide range of surfaces, including those that are rough, curved, and uneven, as well as in various fluids. This means a diver can grip a slippery item without needing to squeeze it tightly and can swiftly snatch it away when necessary.
Managing Difficult Underwater Objects
Because octopus suckers consist of living tissue, they can adjust their shape, expanding and contracting as required for the task at hand. This gives the octopus not only a stronger hold but also the versatility to modify its grip depending on whether it encounters smooth or textured, angular or flat objects.
With the newly developed octopus-inspired adhesive, the research team is able to pick up, hold, and release a variety of challenging underwater items, including both soft and rigid materials that are flat, coarse, or even curved.
This capability was demonstrated when the team constructed an underwater cairn, a carefully arranged pile of stones of different sizes, shapes, and textural properties. The researchers had to pick up the rocks and precisely release them to maintain the balance of the structure, all while also being able to easily handle soft, jelly-like beads.
“Such manipulations are typical for an octopus as it organizes objects around its living space,” explained Lee. “This demonstration showcases the octopus-inspired adhesive’s ability to adeptly manipulate challenging underwater items.”
The materials also exhibit dependable attachment over multiple cycles and for extended durations. In one test, the attachment force remained steady over 100 cycles. In another, the adhesive successfully held onto a rough, curved rock for more than a week underwater before releasing it on cue. This longevity could be vital for salvage operations where maintaining grip over an extended time is necessary.
Octopus-Like Gripping
Bartlett previously introduced the Octa-Glove, detailed in Science Advances. This glove features octopus-like adhesives integrated with LIDAR sensors that detect nearby objects, allowing for a strong yet gentle grip without excessive pressure. Once secured, the suckers can be disengaged as needed to release the object.
This glove could prove beneficial for rescue divers, underwater archaeologists, assistive technologies, as well as healthcare settings where a secure hold on wet or submerged items is essential. The latest research aims to enhance the capabilities of the glove, making its grip even more powerful.
“We aspire to utilize our novel adhesive design to further enhance the Octa-Glove,” stated Bartlett. “Working in underwater environments presents numerous challenges, and this breakthrough helps us overcome yet another obstacle. We are closer than ever to mimicking the remarkable abilities of an octopus to grasp and manipulate objects accurately, which could open up new opportunities for exploration and interaction within aquatic settings.”
