Precision aerosol-jet micropatterning of liquid metal for high-performance flexible strain sensors

Flexible wearable strain sensors are rapidly advancing non-invasive devices, while achieving both an ultra-low detection limit and wide sensing range concurrently presents a challenge. Herein, we propose a liquid metal (LM) strain sensors manufacturing strategy employing aerosol jet printing (AJP). Specially formulated LM ink is the key to enabling high-precision printing (12 μm) of LM via AJP, which is optimized by adjusting the concentration of polyvinylpyrrolidone and diethylene glycol. Additionally, through structured sensor pattern design in conjunction with narrow line width AJP, flexible LM strain sensors are developed that feature an ultralow detection limit (0.1% for l-sinusoid and 0.0033% for s wave LM strain sensors) combined with a wide sensing range (660% for l-sinusoid and 230% for s wave). Exceptional performance achieves comprehensive detection of human movement. This research reconciles the trade-off between detection limit and sensing range, while high-precision LM Aerosol-jet Micro-patterning enhances manufacturing in flexible electronics. The authors report an aerosol jet printing strategy to pattern liquid metal, creating flexible sensors with ultralow detection limits and wide ranges for comprehensive wearable monitoring, from subtle pulses to knee bending.