Ultra-stretchable, Flexible, and Self-Healing Electronics Using a Micromoldable Metal

J.-H. So, M.R. Khan, C. Eaker, M. Mohammed, M.D. Dickey
NC State University, US

Keywords: stretchable electronics, soft materials, liquid metals, self-healing polymer

Summary:

Electronic components that are stretchable and conformal are being developed for flexible electronics and electronic skins. We have been studying new methods to control the shape of a micromoldable liquid metal to create conductors that are soft, self-healing, and ultra-stretchable. The metal is a gallium-based metal alloy that is a low-viscosity liquid at room temperature with low toxicity and negligible volatility. Despite the large surface tension of the metal, it can be molded into non-spherical shapes due to the presence of an ultra-thin oxide skin that forms on its surface. Because it is a liquid, the metal is extremely soft and flows in response to stress to retain electrical continuity under extreme deformation. By embedding the metal into elastomeric substrates, it is possible to form soft electrodes, stretchable antennas, self-healing vascular networks, reconfigurable interconnects, soft sensors, and ultra-stretchable wires that maintain metallic conductivity up to ~800% strain. This talk will discuss the mechanical and electrical properties of this micromoldable liquid metal within the context of stretchable electronics and electronic skins. We will demonstrate several methods to pattern the metal and discuss new applications for flexible electronics.