Check out this video from Carnegie Mellon. It demonstrates the thermally conductive “thubber” material (bottom, labeled LMEE) as it stretches and dissipates the heat of an embedded LED light. The plain rubber material (top) cannot dissipate the heat and ultimately breaks apart under the strain. The second part of the video shows the caudal fin locomotion of a robotic fish. Its thermal actuator is made of “thubber.”
You can find out more about the development of thubber here.