One of the first trade shows I attended when I began my career in the electrics industry was an IPC Flexible Circuits Conference in 2006. A decade ago we were talking about advances in flexible electronics – but no one was mentioning stretchable electronics. Back then, flexible electronics were much more rigid than the electronics we are now looking forward to – they were copper traces on a Mylar (or equivalent) substrate. Flexible electronics are commonplace now.
Recently, scientists at Carnegie Mellon University have been experimenting with a silicone and liquid metal composite material which has some amazing properties. The material is a thermally conductive elastomer. More specifically, it is a silicone material which has pockets of an indium-gallium alloy. This alloy is eutectic indium-gallium (called EGaIn for short) which also goes by “Indalloy™#60” as a trade name. The alloy is 75.5% gallium and 24.5% indium. Because the metal is liquid, it can transfer electricity and heat, while changing form. Here’s a video that will give you a better idea of what’s really going on.
I asked Professor Carmel Majidi for his thoughts on this project, to which he offered: “For the last few years, we’ve been using indium from 
Indium Corporation to synthesize our liquid metal alloys. We see a lot of potential for using indium for making circuits and multifunctional composites that are deformable and mechanically robust. Thubber is a great example of this — with microscopic droplets of indium-based liquid metal alloys in a soft elastomer, we can engineer a composite that has rubber-like elasticity and metal-like electrical and thermal properties.”
We have a lot to look forward to with this new technology in circuit architecture. I would argue that this can change the way we think about electronics applications, and expand what is possible with robotics. More information regarding the technology can be found here, and more information about our wide range of alloys and properties can be found here.
~Jim
*Permission to use image by Carmel Majidi