Liquid metal-elastomer composites for water-resilient soft electronics

Liquid metal-elastomer composites have immense potential for emerging electronic applications due to their exceptional mechanical and functional properties. Underwater exploration is one area of interest for these composites, where divers or robots could benefit from wearable sensing, health monitoring, and energy harvesting. However, the influence of water submersion on liquid metal composites is not well understood. Here, the effect of underwater environments on the mechanical, thermal, and electrical properties of liquid metal composites exposed to month-long aging is quantified. Under most conditions, liquid metal composites maintain their initial properties over the course of aging. However, for composites with high volume loadings of liquid metal (phi$$ \phi $$ = 80%) exposed to saltwater conditions, a decrease up to 70% in tensile modulus and up to 44% in thermal conductivity can occur. The aging environments were not shown to have an effect on the electrical conductivity of the composites. Liquid metal composites are then shown to outperform traditional copper electrodes after saltwater aging, demonstrating these soft, multifunctional composites as strong candidates for wearable, water-resistant devices and machines. image