Flexible pressure and touch sensor with liquid metal droplet based on gallium alloys

Galinstan is a liquid metal based on gallium alloys consisting of gallium, indium and tin at a ratio of 67.5:22.5:10 by weight. It has been received great attention recently since it is fluidic and conductive at room temperature, even safe to humans. By utilizing a fringe capacitance of liquid galinstan, a pressure sensor and an object approach detecting sensor were fabricated. In a pressure sensor, the capacitance increases as the pressure increases and also the performance of the device is reversible by using an elastic PDMS substrate. In an object detecting approach sensor, the device can detect an approach of the grounded object by using fringe capacitance of liquid galinstan droplet and the performance of the device is also reversible.