Layer-by-Layer Flexible Sensors Based on Liquid Metal Droplets with Biomimetic Fin Structures

Flexible sensors have significantly enhanced the convenience of daily life due to their exceptional flexibility and comfort. High sensitivity and multimodal detection capabilities are critical performance metrics for flexible sensors, which motivate ongoing research efforts in the field. Inspired by the dorsal fin patterns of fish, we developed a flexible sensor comprising liquid metal (LM) and polydimethylsiloxane (PDMS) featuring a bionic fin micro–nano structure (BF-PDMS LMFS). By employing PDMS transfer technology to integrate the biomimetic fin micro–nano structure, a significant enhancement in sensor sensitivity has been achieved, reaching a value of 10.2 kPa–1. The BF-PDMS LMFS exhibits rapid response times (0.5 s) and impressive durability and stability, as well as excellent durability and stability (cycling time >10,000 s). Moreover, the BF-PDMS LMFS enables temperature sensing within a range of 20–80 °C, encompassing the majority of ambient temperature fluctuations. This multimodal detection capability significantly broadens the application scope of flexible sensors in real-world scenarios. Additionally, the BF-PDMS LMFS is suitable for dynamic human body detection, allowing real-time monitoring of motor activities, which further expands the potential applications of flexible sensors.