title: Effects of Operating Temperature on Droplet Casting of Flexible Polymer/Multi-Walled Carbon Nanotube Composite Gas Sensors.
abstract: This study examined the performance of a flexible polymer/multi-walled carbon nanotube (MWCNT) composite sensor array as a function of operating temperature. The response magnitudes of a cost-effective flexible gas sensor array equipped with a heater were measured with respect to five different operating temperatures (room temperature, 40 °C, 50 °C, 60 °C, and 70 °C) via impedance spectrum measurement and sensing response experiments. The selected polymers that were droplet cast to coat a MWCNT conductive layer to form two-layer polymer/MWCNT composite sensing films included ethyl cellulose (EC), polyethylene oxide (PEO), and polyvinylpyrrolidone (PVP). Electrical characterization of impedance, sensing response magnitude, and scanning electron microscope (SEM) morphology of each type of polymer/MWCNT composite film was performed at different operating temperatures. With respect to ethanol, the response magnitude of the sensor decreased with increasing operating temperatures. The results indicated that the higher operating temperature could reduce the response and influence the sensitivity of the polymer/MWCNT gas sensor array. The morphology of polymer/MWCNT composite films revealed that there were changes in the porous film after volatile organic compound (VOC) testing.
authors.affiliation: Department of Electrical and Computer Engineering, National Chiao Tung University, 1001 University Road, Hsinchu City 30010, Taiwan. chiou@mail.nctu.edu.tw.|Institute of Electrical Control Engineering, National Chiao Tung University, 1001 University Road, Hsinchu City 30010, Taiwan. chiou@mail.nctu.edu.tw.
authors.forename: Jin-Chern
authors.initials: JC
authors.lastname: Chiou
authors.affiliation: Department of Electrical and Computer Engineering, National Chiao Tung University, 1001 University Road, Hsinchu City 30010, Taiwan. cjwu028@gmail.com.
authors.forename: Chin-Cheng
authors.initials: CC
authors.lastname: Wu
authors.affiliation: Institute of Electrical Control Engineering, National Chiao Tung University, 1001 University Road, Hsinchu City 30010, Taiwan. yuchieh.ece99g@g2.nctu.edu.tw.
authors.forename: Yu-Chieh
authors.initials: YC
authors.lastname: Huang
authors.affiliation: Institute of Biomedical Engineering, National Chiao Tung University, 1001 University Road, Hsinchu City 30010, Taiwan. scchang1222.iie04g@g2.nctu.edu.tw.
authors.forename: Shih-Cheng
authors.initials: SC
authors.lastname: Chang
authors.affiliation: Department of Electrical and Computer Engineering, National Chiao Tung University, 1001 University Road, Hsinchu City 30010, Taiwan. s0450737.eed04g@g2.nctu.edu.tw.
authors.forename: Tse-Mei
authors.initials: TM
authors.lastname: Lin
keywords: droplet casting; impedance spectrum; operating temperature; polymer/multi-walled carbon nanotube composites