Ultralow-hysteresis quartz crystal microbalance humidity sensor based on electrospinned cellulose acetate/konjac glucomannan network-like film

There are numerous and significant uses for accurate and reliable humidity detection in day-to-day living. In this study, a QCM humidity sensor based on cellulose acetate/konjac glucomannan (CA/KGM) film was constructed. The elemental composition, morphology and nanostructure of the film were characterized using scanning electron microscopy (SEM), water contact angle tester, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The CA/KGM QCM humidity sensor exhibited excellent stability, selectivity and repeatability with low humidity hysteresis and short response/recovery time (12.3   s/0.1   s). The experimental results show that the introduction of CA in KGM can dramatically improve the mechanical properties and stability of the composite membrane. The humidity sensing mechanism of the sensor was systematically investigated, and water droplet counting test, fingertip moisture detection and human breath detection were performed. The sensor offers a wide range of potential applications.