Engineering news
Engineers have developed a thermally conductive rubber material, nicknamed “thubber”, that exhibits “an unprecedented combination” of metal-like thermal conductivity and elasticity similar to soft, biological tissue that can stretch up to six times its length.
The electrically insulating composite could be used to create soft, stretchable machines and electronics, according to the research team from Carnegie Mellon University, Pennsylvania.
Carmel Majidi, an associate professor of mechanical engineering at Carnegie Mellon University, said: "Our combination of high thermal conductivity and elasticity is especially critical for rapid heat dissipation in applications such as wearable computing and soft robotics, which require mechanical compliance and stretchable functionality."
Applications could include advanced manufacturing, energy, and transportation. It could also extend to industries like athletic wear and sports medicine, for example, in the creation of lighted clothing for runners and heated garments for injury therapy.
Jonathan Malen, an associate professor of mechanical engineering at Carnegie Mellon University, added: "Until now, high power devices have had to be affixed to rigid, inflexible mounts that were the only technology able to dissipate heat efficiently.
"Now, we can create stretchable mounts for LED lights or computer processors that enable high performance without overheating in applications that demand flexibility, such as light-up fabrics and iPads that fold into your wallet."
The key ingredient in thubber is a suspension of non-toxic, liquid metal microdroplets. The liquid state allows the metal to deform with the surrounding rubber at room temperature. When the rubber is pre-stretched, the droplets form elongated pathways that are efficient for heat travel. Despite the amount of metal, the material is also electrically insulating.
To demonstrate these findings, the team mounted an LED light onto a strip of the material to create a safety lamp worn around a jogger's leg. The thubber dissipated the heat from the LED, which would have otherwise burned the jogger. The researchers also created a soft robotic fish that swims with a thubber tail, without using conventional motors or gears.
Majidi said: "As the field of flexible electronics grows, there will be a greater need for materials like ours. We can also see it used for artificial muscles that power bio-inspired robots."
The findings of the study were published in Proceedings of the National Academy of Sciences.