Hydrophobically Coated Fabric Moisture Sensor with the Gas/Liquid Water Detection Function

Wearable moisture sensors are becoming more widely used in fields such as healthcare, sports fitness, and smart homes. However, many of the sensors are in the form of membranes, which lack breathability and comfort, and their resistance is affected by external pressures, bending motions, and so on. Due to the core-absorption effect of fabrics, fabric-based sensors are often slow to respond and recover or even fail in the presence of high moisture or liquid water. Herein, poly­(3,4-ethylene­dioxythiophene):poly­(styrene­sulfonate) (PEDOT:PSS) hydrophobic fabric-based moisture sensors are prepared. The doped water and oil repellents give the fabric a hydrophobic surface (contact angle = 134.7°), which allows the sensor to detect not only gaseous moisture but also liquid moisture many times over and improves the tolerance to high moisture environments. Moreover, the coated fabric-based moisture sensor still has good breathability (631.7 mm/s). It has a response time of as low as 0.22 s and a high sensitivity of 2.34, and it is capable of detecting the full range of moisture from 0 to 100% RH. Furthermore, the sensor also has outstanding stability and accuracy in detection when under the conditions of external pressure and bending. This work presents a feasible and cost-effective approach to monitoring breath in real time, showing its potential use in wearable devices.