High performance and reusable SAW sensor coated with POSS-thiourea based polymer for DMMP detection

초록

CWAs can have a fatal effect on humans even in small amounts, which can cause fatal human casualties if they are not detected early during air diffusion. In addition, it could be used highly poisonous chemical in warfare, the importance of developing gas sensors capable of detecting chemical warfare agents (CWAs) to prepare for threats against them has increased. In this study dimethyl methylphosphonate (DMMP) is used as a simulant, which has similar chemical structure to G-series nerve agents especially sarin. Here in, 250 MHz surface acoustic wave (SAW) sensor was used for low concentration detection of CWAs simulant. The SAW sensor has a characteristic of detecting various materials according to the type of sensing material coated on the delay line region of the sensor. The receptor coated on the SAW sensor was polyhedral oligomeric silsesquioxane combined with thiourea-based polymer, and the functional group 3,5-bis(trifluoromethyl)phenyl was attached. This receptor combines with the CWAs Simulant to cause a mass change and cause a frequency shift in the SAW sensor. In the experiment, DMMP vaporized through a permeation tube to generate a specific concentration, and the experiment was conducted for a total of 450 seconds i.e., 150 seconds of nitrogen purging, 150 seconds of DMMP adsorption, and 150 seconds of DMMP desorption by nitrogen purging. In the repeated experiment, at the concentration of DMMP 1 ppm, 300 seconds DMMP adsorption and 300 seconds nitrogen purging were repeated three times after 300 seconds of nitrogen purge to stabilize the sensor.