A High-Performance Strain Sensor for the Detection of Human Motion and Subtle Strain Based on Liquid Metal Microwire

Abstract

Flexible strain sensors have a wide range of applications, such as human motion monitoring, wearable electronic devices, and human–computer interactions, due to their good conformability and sensitive deformation detection. To overcome the internal stress problem of solid sensing materials during deformation and prepare small-sized flexible strain sensors, it is necessary to choose a more suitable sensing material and preparation technology. We report a simple and high-performance flexible strain sensor based on liquid metal nanoparticles (LMNPs) on a polyimide substrate. The LMNPs were assembled using the femtosecond laser direct writing technology to form liquid metal microwires. A wearable strain sensor from the liquid metal microwire was fabricated with an excellent gauge factor of up to 76.18, a good linearity in a wide sensing range, and a fast response/recovery time of 159 ms/120 ms. Due to these extraordinary strain sensing performances, the strain sensor can monitor facial expressions in real time and detect vocal cord vibrations for speech recognition.

Combinatorial Bionic Hierarchical Flexible Strain Sensor for Sign Language Recognition with Machine Learning

“…We compared the main sensing performances of our sensor to those of other piezoresistive flexible strain sensors, as shown in Figure f. The CBH-sensor exhibits high performances between balancing sensitivity and wide sensing range, outperforming the serpentine or wrinkles/cracks piezoresistive strain sensors ,− reported in the literature to the best of our knowledge (Table S2, Supporting Information). Although the sensitivity or sensing range is lower than that of some strain sensors based on new material or architecture designs, they still cannot handle well to achieve a trade-off between sensitivity and the sensing range.…”