Email Print Share
January 21, 2021

Smart hydrogel uses light to change shape and color

Rutgers University engineers have developed a 3D printable hydrogel, or smart gel, that senses light and changes shape as a result. The engineers incorporated a light-sensing nanomaterial in the hydrogel, turning it into an “artificial muscle” that contracts in response to changes in light. The light-sensing smart gel, combined with the 3D-printed stretchy material, changes color, resulting in a camouflage effect.

Credit: National Science Foundation/Karson Productions

Hidden in plain sight.

I'm Bob Karson with the Discovery Files, from NSF -- the U.S. National Science Foundation.

(Sound effect: undersea sounds) Nature has provided octopi, squid and cuttlefish with some mind-blowing camo gear. The ability to change the color and texture of their skin to blend in with the surroundings. Now engineers at Rutgers have successfully re-created these abilities in a 3d-printed smart gel that changes shape when exposed to light and reveals colors when light changes.

The sea creatures do it with color-changing cells in their skin called Chromataphores. To copy those, the engineers start with a hydrogel. Think, Jell-O or soft contacts -- hydrogels keep their shape and stay solid and flexible despite being filled with water.

This hydrogel is infused with a light-sensing nanomaterial, turning it into an artificial muscle that expands and contracts in response to light. That expands the stretchy material to reveal color for a camouflage effect.

Military camouflage and soft robotics could benefit from this. Electronic displays are another possible application because new materials allow for a more complete interface with existing surfaces.

(Sound effect: ratchet sound) The team is fine-tuning for sensitivity, response time, scalability, durability and packaging. A color-changing artificial muscle. (Sound effect: undersea sounds) Inspired by some elusive denizens of the deep.

Now, where's my octopus? He was just here.

"The discovery files" covers projects funded by the government's National Science Foundation. Federally sponsored research -- brought to you, by you! Learn more at or on our podcast.

Images and other media in the National Science Foundation Multimedia Gallery are available for use in print and electronic material by NSF employees, members of the media, university staff, teachers and the general public. All media in the gallery are intended for personal, educational and nonprofit/non-commercial use only.

Images credited to the National Science Foundation, a federal agency, are in the public domain. The images were created by employees of the United States Government as part of their official duties or prepared by contractors as "works for hire" for NSF. You may freely use NSF-credited images and, at your discretion, credit NSF with a "Courtesy: National Science Foundation" notation.

Additional information about general usage can be found in Conditions.