title: Development of a Room Temperature SAW Methane Gas Sensor Incorporating a Supramolecular Cryptophane A Coating.
abstract: A new room temperature supra-molecular cryptophane A (CrypA)-coated surface acoustic wave (SAW) sensor for sensing methane gas is presented. The sensor is composed of differential resonator-oscillators, a supra-molecular CrypA coated along the acoustic propagation path, and a frequency signal acquisition module (FSAM). A two-port SAW resonator configuration with low insertion loss, single resonation mode, and high quality factor was designed on a temperature-compensated ST-X quartz substrate, and as the feedback of the differntial oscillators. Prior to development, the coupling of modes (COM) simulation was conducted to predict the device performance. The supramolecular CrypA was synthesized from vanillyl alcohol using a double trimerisation method and deposited onto the SAW propagation path of the sensing resonators via different film deposition methods. Experiential results indicate the CrypA-coated sensor made using a dropping method exhibits higher sensor response compared to the unit prepared by the spinning approach because of the obviously larger surface roughness. Fast response and excellent repeatability were observed in gas sensing experiments, and the estimated detection limit and measured sensitivity are ~0.05% and ~204 Hz/%, respectively.
authors.affiliation: State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, No. 21, BeiSiHuan West Road, Beijing 100190, China. wangwenwq@mail.ioa.ac.cn.
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, No. 21, BeiSiHuan West Road, Beijing 100190, China. huhaoliang11@mails.ucas.ac.cn.
authors.forename: Haoliang
authors.initials: H
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, No. 21, BeiSiHuan West Road, Beijing 100190, China. liuxinlu1987@foxmail.com.
authors.forename: Xinlu
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, No. 21, BeiSiHuan West Road, Beijing 100190, China. heshitang@mail.ioa.ac.cn.
authors.forename: Shitang
authors.initials: S
authors.lastname: He
authors.affiliation: State Key Laboratory of NBC Protection for Civilian, Yangfang, Changping District, Beijing 102205, China. panyjingyu2011@sina.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Pan
authors.affiliation: School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China. chzhang@sxu.edu.cn.
authors.forename: Caihong
authors.initials: C
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China. dc@sxu.edu.cn.
authors.forename: Chuan
authors.initials: C
authors.lastname: Dong
keywords: cryptophane A; methane gas sensor; resonator-oscillator; room temperature; surface acoustic wave