Piezoelectric quartz crystal humidity sensor using chemically modified nitrated polystyrene as water sorbing coating

The application of CNT/Nafion composite material to low humidity sensing measurement

“…Neshkova et al [6] used modified nitrated polystyrene as the sensing material to measure relative humidity (RH) in the range of 10-90%. The humidity sensor exhibited high sensitivity (up to 40 Hz per %RH), fast response time (<3 s), good reproducibility and stability with long-term investigation of more than 3 months.…”

“…Different sensing techniques, impedance [1], capacity [2], optics [3], field effect transistors (FET) [4], surface acoustic wave (SAW) [5] and quartz crystal microbalance (QCM) [6][7][8][9] have been explored to detect humidity. In many industries, low humidity detection has become extremely important.…”

“…Of the various sensing technologies for humidity detection referred to the above, QCM detectors have a low detection limit and wide measuring range. Different sensing materials were prepared as films coated on the electrode of QCM in order to detect vapor and humidity [6][7][8][9].…”

Electro-synthesized Conjugated Salen Polymer-Glassy Carbon as Hydrochromic Reflective Filter for Humidity Detection: Introduction of Humidity Optical Sensor

“…Then the modified GC electrode was introduced from one side of the cell. Also from the opposite, side a white light LED, as well as a digital camera (model: AGPtek, magnifying ratio: X 800) were positioned with angle between [10][11][12][13][14][15][16][17][18][19][20] o versus the GC carbon electrode. Also to remove the hysteresis of the GC electrode from any adsorption and diffusion of humidity, an IR light source was positioned next to the GC electrode to eliminate the memory effect.…”

“…surface acoustic waves (SAWs) [7], inter-digitated circuit [8], electronic devices such as field effect transistors (FETs) [9][10][11], quartz crystal microbalance [12][13][14][15] and optical detection system [16], have been investigated for humidity detection and determination. However between these ranges of sensing methods, optical sensing has been selected in this study, because of its significant advantages such as improved detection system, fast response time, high sensitivity and its wide linear response [16].…”