Orange dye-polyaniline composite based impedance humidity sensors

• Published in: Chinese physics B Vol. 22; no. 1; pp. 161 - 166
• Main Authors: Chani, Muhammad Tariq Saeed, Karimov, Kh. S., Khalid, F. A., Abbas, S. Z., Bhatty, M. B.
• Format: Journal Article
• Language: English
• Published: 2013
• Subjects: Annealing; Dyes; Electrodes; Humidity; Impedance; Recovery time; Relative humidity; Sensors; Water vapor; 吸收; 恢复时间; 染料; 橙色; 测量频率; 湿度传感器; 聚苯胺复合材料; 解吸; 阻抗
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/22/1/010701

This study presents the fabrication and investigation （PANI） composite films. A blend of 3 wt.% OD with 1 of humidity sensors based on orange dye （OD） and polyaniline wt.% PANI was prepared in 1 ml water. The composite films were deposited on glass substrates between pre-deposited silver electrodes. The gap between the electrodes was 45 um. The sensing mechanism was based on the impedance and capacitance variations due to the absorption/desorption of water vapor. It was observed that with the increase in relative humidity （RH） from 30% to 90%, the impedance decreases by 5.2 × 10^4 and 8.8 × 10^3 times for the frequencies of 120 Hz and 1 kHz, respectively. The impedance-humidity relationship showed a more uniform change compared to the capacitance-humidity relationship in the RH range of 30% to 90%. The consequence of annealing, measuring frequency, response and recovery time, and absorption-desorption behavior of the humidity sensor were also discussed in detail. The annealing resulted in an increase in sensitivity of up to 2.5 times, while the measured response time and recovery time were 34 s and 450 s, respectively. The impedance-humidity relationship was simulated.