Towards nm scale continuous thin film of liquid metals for stretchable electronics
Advancements in soft robotics and wearable technologies have led to an increased need for flexible and stretchable electronic systems. Liquid metals like Gallium and it’s alloys offer high potential in the field of stretchable electronics and photonics due to their inherent high conductivity and malleability. However, their high surface tension typically results in micron-sized droplets hence not adaptable to have sub -100 nm film thickness yet maintaining the high conductivity crucial for applications in stretchable electronics. Hereby, for the first time, we present a novel fabrication strategy for soft electronics using a monolayer of Ga nanodroplets less than 100 nm thick on polymeric as well as elastomeric substrates. By enhancing the surface energy of the polymers, we create uniform Ga nanodroplets capable of sustaining stretchability up to 200% strain. Our devices exhibit electronic conduction primarily through tunneling and display piezoresistive characteristics, which are explained using Kirchhoff’s resistive network and Simmon’s analytical tunnelling current model. To showcase the device’s capability in fields of stretchable electronics, we demonstrate several functional prototypes, including flexible devices integrated with LEDs, curvature and pressure sensors, and soft robotic grippers capable of sensing object curvature. These findings open new avenues for the development of efficient, scalable, and highly adaptable stretchable electronics, with promising implications for future soft robotics and wearable technologies.