Investigation of healing electronic pressure-sensitive soft switch based on liquid metal microfiber

Abstract

Flexible and wearable electronics have gained extensive attention in health monitoring, electronic skin, and sensors due to their flexibility, portability, sensitivity, and biocompatibility. Liquid metal (LM) is an optimum conductive material for soft electronic devices because of its high conductivity and fluidity at room temperature. Nevertheless, LM electronic devices with stable dimension is a formidable challenge due to its relatively high surface tension and mass density. In this study, we introduce a wet spinning approach that utilises sodium alginate as the exterior phase and LM as the interior phase. Calcium lactate is used to solidify the sodium alginate, thereby producing liquid metal microfibers (LMMs). The LMMs can be modified by adjusting the flow rate of the two-phase materials. The encapsulated LM microcapsule can serve as a healing electronic soft switch that is suitable for use in wearable and flexible electronic devices. Initially, the liquid metal soft switch (LMSS) has a high resistance value. Once a specific amount of pressure is applied, the resistance value drops considerably resulting in the switch’s activation. And LMMs coated by the sodium alginate can dissolve in a trisodium citrate solution, so that the LM can be reshaped under mixed each other. It achieves LMSS’s reusability and recycling.