Amidoxime Functionalized Coatings for Surface Acoustic Wave Detection of Simulant Vapors

摘要

The preparation of thin film coatings with highly sensitive and specific absorption for particular vapors is a critical requirement for the development of chemical electronic microsensors as point detectors. In this work, coatings that have a specific interaction with simulants for nerve agents are being investigated using a surface acoustic wave (SAW) device. The SAW device detects extremely small gravimetric changes in a coating by registering a frequency shift in the resonance of the piezoelectic substrate. In this work, the objective is to incorporate a functional group that has specific reactivity toward nerve agent simulants in the thin film coating of a SAW device and to evaluate the detector's response to the simulant's vapor. Coatings were prepared for a surface acoustic wave (SAW) sensor that would have a chemical specificity and sensitivity toward phosphonate ester agent simulants. Terpolymer coatings of varying compositions of butadiene, acrylonitrile, an acrylamidoxime were prepared and evaluate for chemical sensitivity toward methanesulfonyl fluoride (MSF) and dimethyl methylphosphonate (DMMP) simulants. Chemical reactivity was monitored by infrared spectroscopy and physical adsorption by SAW frequency measurements. The amidoxime functional group did to react rapidly and quantitatively with the MSF vapor. Both simulants were physically adsorbed by the coating, the degree of which is correlated with solubility parameters, vapor pressures, and glass transition temperatures.