Solution-Processed Sensing Textiles with Adjustable Sensitivity and Linear Detection Range Enabled by Twisting Structure.

Wearable strain sensors are emerging rapidly for their promising applications in human motion detection for diagnosis, healthcare, training instruction, and rehabilitation exercise assessment. However, it remains a bottleneck in gaining comfortable and breathable devices with the features of high sensitivity, linear response, and tunable detection range. Textiles possess fascinating advantages of good breathability, aesthetic property, tailorability, and excellent mechanical compliance to conformably attach to human body. As the meandering loops in a textile can be extended in different directions, it provides plenty of room for exploring ideal sensors by tuning a twisting structure with rationally selected yarn materials. Herein, textile sensors with twisting architecture are designed via a solution-based process by using a stable water-based conductive ink that is composed of polypyrrole/polyvinyl alcohol nanoparticles with a mean diameter of 50 nm. Depending on the predesigned twisting models, the thus-fabricated textile sensors show adjustable performances, exhibiting a high sensitivity of 38.9 with good linearity and a broad detection range of 200%. Such sensors can be integrated into fabrics and conformably attached to skin for monitoring subtle (facial expressions, breathing, and speaking) and large (stretching, jumping, running and jogging, and sign language) human motions. As a proof-of-concept application, by integrating with a wireless transmitter, the signals detected by our sensors during exercise (e.g., running) can be remotely received and displayed on a smartphone. It is believed that the integration of our textile sensors with selected twisting models into a cloth promises full-range motion detection for wearable electronics and human-machine interfaces.