Effects of temperature and humidity on the performance of a PECH polymer coated SAW sensor.

Yong Pan,Xufeng Xue,Wen Wang,Weiwei Liu,Bingqing Cao,Caihong Zhang,Lin Zhang

doi:10.1039/d0ra02502j

Yong Pan, Xufeng Xue + Show 5 more

Open Access

https://doi.org/10.1039/d0ra02502j

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Abstract

The influences of environment, such as temperature, humidity and interfering gases, on the performance of a surface acoustic wave (SAW) sensor in the detection of 2-chloroethyl ethyl sulfide (CEES) were invested. The 150 MHz SAW dual delay lines were used, coated with a poly(epichlorohydrin) (PECH) thin layer, and CEES was detected under different concentrations. Linear correlation between the frequency-shift and the exposure time of the sensor to CEES could be observed, and the limit of CEES could be detected as low as 1.5 mg m−3. Under different temperature (0–50 C°) and humidity (30–80% RH) conditions, CEES was detected by the fabricated SAW sensor coated with PECH, the frequency shifts were measured and the performance of the sensor was evaluated. The results proved that temperature and humidity were the most important factors to influence the performance of SAW sensors; with the decreasing of temperature and the increasing of humidity, there would be larger frequency shifts. In the interference experiments, it was found that most gases existing in the environment in high concentrations would not influence the detection of CEES. Then, the SAW sensor having been fabricated was kept under the conditions of 25 °C and 35% RH for 18 months to further verify the quality, and CEES was detected every so many months. It proved that the performance of the sensor would decrease about 16.39% after 18 months. Although it reflected the attenuation of the sensor to some extent, the sensor was still in good condition. Additionally, the related mechanisms were also discussed.

Highlights

Chemical warfare agents (CWAs) are powerful weapons and a threat for the world; these agents still remain a threat especially from some countries and terrorists as these CWAs are easy to manufacture and have devastating effects
As the chloroethyl ethyl sulfide (CEES) concentration increased, the sensing response increased, and it was quite linear for CEES at the concentrations of 1.2–10 mg mÀ3, the sensitivity de ned by the tted slope was evaluated as 233.17 Hz/(mg mÀ3)
To further verify the short term repeatability of the PECHcoated surface acoustic wave (SAW) sensor, four successive experiments were carried out, Fig. 6(b), it showed that the sensor was reproducible, we suggested that the proposed SAW gas sensor coated with PECH sensitive lms was very promising for CEES gas detection application

Summary

Introduction

As one of the most important CWAs, mustard gas, named bis(2-chloroethyl) sul de (HD), is a typical vesicant agent in chemical agent having been known, it has the title of “king of CWAs gas”. It can result in serious injury and possible death even at very low concentration because of its highly toxicity, and has extensive damage to the animal and humanity.

Conclusion

Results and discussion

Conclusions