Assistant Professor James Pikul helped developed technology known as CCOARSE, or Circumferentially Constrained and Radially Stretched Elastomer. The combination of stretchy silicone and precisely placed inflexible mesh allows 2D sheets to be inflated into predetermined 3D shapes. Pikul and his collaborators took inspiration from octopus skin, which uses a similar texture-changing trick to mimic rough surfaces. (J. H. Pikul et al. Science 2017)

New Penn Engineering Professor is Developing Artificial Octopus Camouflage

In a blink of an eye, an octopus can transform from a colorful creature to a drab pile of rocks and plant life, indistinguishable from the surface it’s perched on. This camouflage relies on specialized pigment organs, but what makes the octopus unique among animals is their ability to change the texture of their skin. Previously flat stretches can bulge out in patterns that complete the illusion.

Octopus camouflage in action, courtesy of Roger Hanlon, a senior scientist at the Marine Biological Laboratory and one of the study’s co-authors.

James Pikul, one of the newest faculty members in the School of Engineering and Applied Science’s Department of Mechanical Engineering and Applied Mechanics, is taking inspiration from these and other cephalopods, developing a deeper understanding of the physics that allow 2D surfaces to transform into 3D shapes.

James Pikul

In a paper published in the journal Science, Pikul and coauthors outline a method for achieving this transformation they have dubbed CCOARSE, or Circumferentially Constrained and Radially Stretched Elastomer.

Consisting of a stretchy silicone layer imbued with an inflexible fiber mesh in precise locations, the material can be inflated like a balloon into a predetermined 3D shape.

Pikul helped developed CCOARSE with colleagues at Cornell University, where he conducted worked as postdoctoral researcher, under Itai Cohen, professor of physics in the College of Arts and Sciences, and Rob Shepherd, assistant professor in the Sibley School of Mechanical and Aerospace Engineering. The three are now patenting the technology.

FArtificial papillae (J. H. Pikul et al. Science 2017)

Their inspiration came from cephalopods’ papillae, bumps that extend from the skin as the result of erector muscles below. The researchers developed CCOARSE to act as synthetic tissue groupings that mimic the papillae’s shape-changing behavior, producing bumps and bulges in varying shapes and sizes. A simple algorithm determines where fibers must be placed in the silicone sheet to achieve the desired final form.

Given the complexity of cephalopod’s camouflage system, Pikul envisions even finer-grained control over CCOARSE’s ultimate shape as being possible.

“Cephalopods have different subsets of papillae and activate them in different combinations depending on what surface texture they want to mimic,” Pikul says. “We could begin thinking about CCOARSE like pixels on a display. Each individual shape change would be relatively simple, but combined, you could achieve complex results.”

Eventual applications could include disappearing computer displays, virtual reality interfaces that give users touch feedback and medical devices, such as balloon catheters that take complex shapes when inflated.

“We’re even thinking about more fun ways to use this technology, like in architecture and fashion,” Pikul says.

CCOARSE mimicking a succulent plant. (J. H. Pikul et al. Science 2017)

Pikul’s work on CCOARSE is part of his larger research interests in using soft matter to engineer new materials on multiple scales. Soft matter at the nanoscale can be used to make batteries that charge in seconds, or materials that increase the operating range of robots or vehicles by being lighter while also having a higher structural strength.

Soft materials could also be useful in developing soft robots that use elements of CCOARSE’s technology to change their shapes. Adding chemical and physical function to these stretchable materials that transform their surface texture would enable a wider range of applications for these robots.

For more information, see stories about CCOARSE at Cornell and Science.