A High-Stability QCM Humidity Sensor Coated With Nanodiamond/Multiwalled Carbon Nanotubes Nanocomposite

In this paper, a high-stability QCM humidity sensor coated with nanodiamond (ND)/multiwalled carbon nanotubes (MWCNTs) nanocomposite film was purposed based on good dispersion of MWCNTs in ND solution. The experimental results demonstrated that the sensor not only had a relative high frequency shift with humidity change, but also maintained a high quality (Q) factor compared with that of pure ND film coated sensor. In high humidity, the Q factor of ND/MWCNTs coated sensor is about four times larger than that of pure ND coated sensor, and can retain negligible change as long as several months. The possible reason was analyzed and discussed. Moreover, the sensor exhibited low hysteresis, fast response/recovery time, and good repeatability.