Yarn-based superhydrophobic wearable sensors for ammonia gas detection at room temperature

Abstract

Conventional metal-oxide-semiconductor (MOS) gas sensors are limited in wearable gas detection due to their non-flexibility, high operating temperature, and less durability. In this study, a yarn-based superhydrophobic flexible wearable sensor for room-temperature ammonia gas detection was prepared based on the nano-size effect of both nanocore yarns prepared through electrostatic spinning and MOS gas-sensitive materials synthesized via a two-step hydrothermal synthesis approach. The yarn sensor has a response sensitivity of 13.11 towards 100 ppm (1 ppm = 10⁻⁶) ammonia at room temperature, a response time and a recovery time of 36 and 21 s, respectively, and a detection limit as low as 10 ppm with the sensitivity of up to 4.76 towards ammonia. In addition, it displays commendable linearity within the concentration range of 10–100 ppm, accompanied by remarkable selectivity and stability, while the hydrophobicity angle reaches 155.74°. Furthermore, its sensing performance still maintains stability even after repeated bending and prolonged operation. The sensor also has stable mechanical properties and flexibility, and can be affixed onto the fabric surface through sewing, which has a specific potential for clothing use.