Rutgers engineers have developed a 3D-printable hydrogel, or smart gel, which incorporates a light-sensing nanomaterial. Despite containing water, hydrogels keep their shape and stay solid. Examples are found in the human body, Jell-O, diapers and contact lenses.
When the material senses light, it changes shape. Engineers have turned it into an “artificial muscle” that contracts in response to changes in light. It also changes color, resulting in a camouflage effect.