Real-time detection of styrene using SAW sensors based on hexafluoroisopropanol group functionalized hydrogen-bond acidic polymers

• Firstly introduced HBA polymers coated SAW sensors for styrene detection.
• We confirmed the OH/π hydrogen bond interaction for HBA polymers and styrene.
• The HBA sensors demonstrated high sensitivity and high selectivity to styrene vapor.
• Two HBA polymers were synthesized by one-step hydrosilylation.
• We did not use conventional highly toxic hexafluoroacetone gas as the raw material.

Hydrogen-bond acidic (HBA) polymers are well-established adsorbents for organophosphorus compounds and nitroaromatic explosives detection. In this paper, we report two HBA polymers for detection of styrene vapors based on 434-MHz surface acoustic wave (SAW) chemical sensors. These polymers, dubbed PLF and LSFA, are pendent hexafluoroisopropanol (HFIP)-group modified polysiloxanes, which were synthesized by one-step hydrosilylation reaction. Real-time response studies of these two sensors showed that they are highly sensitive to styrene vapors with excellent selectivity. After exposure to 5 mg/m3 styrene vapor, the frequency shifts of the PLF and LSFA sensors have increased by 6.3 kHz and 3.2 kHz, respectively. The polymers are 20-fold less sensitive to toluene than to styrene while they have comparable sensitivity to 1-butene. In situ infrared spectroscopy studies demonstrated that the polymer–styrene interaction is attributed to the OH/π hydrogen bond between HFIP groups of the polymers and the ethylene group of styrene molecules.