| A surface acoustic wave (SAW) chemical sensor is a kind of vapor sensor which has been utilized to detect and monitor toxic or hazardous gases such as chemical weapon agents or explosives in real-time. Reversible sorption can happen between sensing film on SAW sensor and the analyte. Some characters of SAW sensor such as spreading speed between different phases will be changed for the sorption. In result of the aforementioned changes, a corresponding alteration will happen to the frequency, so the quantitative analysis can be carried out.Adsorbent material Poly(methyl(4-hydroxy-4,4-bis(trifluoromethyl)but-1- yl)siloxane)(SXFA) was synthesized by reaction of polyallylmethylsiloxane and hexafluoroacetone(HFA). Because of hydroxyl on the substitute group on polyallylmethylsiloxane, SXFA exhibit hydrogen-bond acidity. Some traditional explosives, such as DNT, TNT, have hydrogen-bond basicity. It is possible that SXFA can be utilized to detecting these warfare explosives.Polyallylmethylsiloxane with different molecular weights is synthesized by anionic ring-opening polymerization, characterized by infrared spectrum and GPC in this paper. The SXFA was synthesized from Polyallylmethylsiloxane and hexafluoroaceton (HFA) and characterized by infrared spectrum, ion chromatograph and hydroxyl analysis. The polymer was coated on the piezocrystal by two methods of solvent evaporation and spin coating. In the gas supply system, 2,4-dinitrotoluene (DNT) was used as simulation gas, and the responses of SAW sensor were tested at DNT concentration of 750mg/m3.Polyallylmethylsiloxane with narrow molecular mass distribution was obtained by adding different amounts of initiator. In the synthesis of SXFA, the influences of reaction time, solvent, reaction temperature and are investigated. By the result of Characterization, best process conditions were selected. In the adsorption test, the influences of solution strength and coating methods on response are discussed. |
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