U-shaped microfiber sensor coated with PVA nanofibers for the simultaneous measurement of humidity and temperature

In order to measure humidity and temperature simultaneously, a U-shaped microfiber strain sensor coated with polyvinyl alcohol (PVA) nanofibers is proposed in this paper. The PVA nanofibers and U-shaped microfiber are prepared by electrospinning technology and hydrogen-oxygen flame heating technology, respectively. The sensing mechanism is that the radius of U-shaped microfiber will change when the temperature and humidity change, because the expansion and stress-strain properties of the coated PVA nanofibers are tightly related with inside water content which can be greatly influenced by the temperature and humidity in the environment. The temperature and humidity are measured by the wavelength changes of the resonant dips of the sensors. The experimental results show that the average sensitivity of the sensor is 0.21 nm/%RH in the range of 20 %RH to 75 %RH, and the average sensitivity is -0.19 nm/degrees C in the temperature range from 30 degrees C to 50 degrees C. Sensors with excellent performance (good repeatability, fast dynamic response, and stability) in this work are expected to play a role in practical applications in many industries.