Characterization of Highly-Stretchable Screen-Printed Liquid Metal Pressure Sensors

The sensitivity of three different screen-printed highly stretchable liquid metal (Galinstan) sensors towards temperature and humidity as well as their electrical behavior under compressive load were studied. The sensors' resistances show quasi linear dependence on changes in temperature without any hysteresis. Depending on the individual sensor design, changes in capacitance of up to 76% due to wetting of the sensor area with tap water have been observed. When applying compressive force, the capacitance values of all sensors show non-linear dependence and small hysteresis. In capacitive sensing mode, all sensors were especially sensitive to small forces (<4N). These results qualify Galinstan as promising candidate for future highly- stretchable, flexible electronics applications, such as the development of electronic skin and artificial nervous systems for biomedical and soft robotics applications.