A Capacitive Humidity Sensor Based on Multi-Wall Carbon Nanotubes (MWCNTs)
Open Access
- 15 September 2009
- Vol. 9 (9), 7431-7444
- https://doi.org/10.3390/s90907431
Abstract
A new type of capacitive humidity sensor is introduced in this paper. The sensor consists of two plate electrodes coated with MWCNT films and four pieces of isolating medium at the four corners of the sensor. According to capillary condensation, the capacitance signal of the sensor is sensitive to relative humidity (RH), which could be transformed to voltage signal by a capacitance to voltage converter circuit. The sensor is tested using different saturated saline solutions at the ambient temperature of 25 °C, which yielded approximately 11% to 97% RH, respectively. The function of the MWCNT films, the effect of electrode distance, the temperature character and the repeatability of the sensor are discussed in this paper.Keywords
This publication has 25 references indexed in Scilit:
- Quartz crystal microbalance coated with carbon nanotube films used as humidity sensorSensors and Actuators A: Physical, 2005
- Electrical and humidity sensing properties of carbon nanotubes-SiO2-poly(2-acrylamido-2-methylpropane sulfonate) composite materialSensors and Actuators B: Chemical, 2005
- Capacitive humidity sensing properties of hydrothermally-etched silicon nano-porous pillar arraySensors and Actuators B: Chemical, 2004
- Impedance of humidity sensitive metal/porous silicon/n-Si structuresSensors and Actuators A: Physical, 2003
- Room Temperature Ammonia and Humidity Sensing Using Highly Ordered Nanoporous Alumina FilmsSensors, 2002
- A Ceramic Thick Film Humidity Sensor Based on MnZn FerriteSensors, 2002
- Comparative study on micromorphology and humidity sensitive properties of thin-film and thick-film humidity sensors based on semiconducting MnWO4Sensors and Actuators B: Chemical, 2000
- Effect of humidity on microwave dielectric losses of porous aluminaJournal of Applied Physics, 1999
- Helical microtubules of graphitic carbonNature, 1991
- A polyimide-based capacitive humidity sensorIEEE Transactions on Electron Devices, 1985