Sensing mechanism and development of conducting polyaniline gas sensor and system

Nowadays, for the demand of comfortable and safe environment, the development of gas sensor is heading for reducing the volume and achieving the micro portable system. Furthermore, the gas sensor needs to achieve the low power and precise measurement in the future. In so many gas sensing materials, conducting polyaniline gas sensing material is attached importance because it can be manufacturing for the small area sensing electrode and portable gas sensing system. The sensing mechanism of conducting polyaniline(PANI) is making use of the conductivity change when the polyaniline material detects the gas. So it has the capability of gas sensing and is very convenient for monitoring the specific toxic gases. However, in the gas sensing field of making use of polyaniline material, the understanding of sensing mechanism still have a lot of places not clear and need to breakthrough. Therefore, manufacturing conducting polyaniline material electrode can detect the specific gas, demonstrating and discussing the sensing mechanism clearly are the primary content in this study.
The sensing gas of this study is trimethylamine. In the experiment, we find the polyaniline sensing electrode has obvious response of trimethylamine. Then we proceed to test the reproducibility of gas sensing and find that has not good reproducibility. Thus, we detect triethylamine another kind of tertiary amine and find the result is similar. Therefore, we infer that the chemical interaction happens in the sensing process so it is hard to have the reproducibility of sensing electrode. After we further analyze the material on the sensing electrodes which are before, in and after the sensing process with UV-Vis and FTIR spectrum analysis. It proves clearly the polyaniline material happens the chemical reaction on the sensing electrode in the sensing trimethylamine process. And we analyze the characteristics of material and which functional groups change of the mechanism in detail. So, in this study, we provide the evident and important demonstration and analysis for the unclear related sensing mechanism in the gas sensing field.