A CO2 Sensor Using a Quartz Crystal Microbalance Coated with a Sensitive Membrane. Issue 2 (February 2014)

• Record Type: Journal Article
• Authors: Muraoka, Shigenobu; Kiyohara, Yuya; Oue, Hiroyoshi; Higashimoto, Shinya
• Is Part Of: Electronics and communications in Japan. Volume 97:Issue 2(2014:Feb.)
• Page Start: 60
• Page End: 66
• Publication Date: 2014-02
• Subjects: Electronics -- Periodicals; Telecommunication -- Periodicals; 621.6805
• DOI: 10.1002/ecj.11601
• Languages: English
• ISSNs: 1942-9533

Abstract

<abstract abstract-type="main"> <title>SUMMARY</title> <p>We attempted to fabricate a CO₂ sensor that utilizes a quartz crystal microbalance (QCM) coated with an acrylonitrile–styrene copolymer (AS) sensitive membrane. The concentration of CO₂ gas diluted with dry N₂ gas was determined by measuring the shift in the resonant frequency of the QCM. Since the Earth's atmosphere consists of N₂, O₂, CO₂, Ar, and moisture, the sensitivity of the QCM to Ar, O₂, and humidity was also examined. It was shown that AS‐coated QCMs are sensitive not only to CO₂ but also to humidity, but are insensitive to O₂ and Ar. The relationship between the concentration of CO₂ gas diluted with damp N₂ gas and the frequency shifts in the QCMs was examined. It was found that the frequency shift compensated for humidity is almost the same as the frequency shift caused by CO₂ gas diluted with dry N₂ gas. Hence, it was demonstrated that the concentration of CO₂ gas in the Earth's atmosphere can be measured using a QCM. It was also found that the sensitivities to the concentration of CO₂ and to humidity increase with increasing thickness of the AS membrane.</p> </abstract>