A new siloxane polymer for chemical vapor sensor

A new hexafluoroisopropanol groups functionalized hydrogen-bond acidic siloxane polymer for quartz crystal microbalance sensor (QCMs) application was synthesized via O-alkylation, Claisen rearrange, hydrosilylation and hexafluoroacetone groups (HFA) electrophilic addition reactions. This hexafluoroisopropanol-functionalized siloxane polymer was confirmed by FT-IR and H-1 NMR, and coated onto an AT-cut 8 MHz QCM sensor to investigate its gas sensitive responses to eight different typical organic volatile chemical vapors. The results indicated that this new siloxane polymer exhibited an excellent performance on the detection of the organophosphorus nerve agent stimulant dimethyl methylphosphonate (DMMP) vapor, and the frequency changes of this functionalized siloxane polymer based QCM sensors to the DMMP vapor were completely linear and with a regression coefficient of 0.9993 in the concentration range of 10-60 ppm. In addition, the sensitivity of the fabricated QCM sensor to DMMP was up to 23.07 Hz/ppm, and it is much higher than that of the other chemical vapors under the same circumstances, the detection limits (LODs) of this fabricated QCM sensor was obtained as low as 0.13 ppm. (C) 2010 Elsevier B.V. All rights reserved.