Novel low humidity sensor made of TiO2 nanowires/poly(2-acrylamido-2-methylpropane sulfonate) composite material film combined with quartz crystal microbalance

A novel ceramic nanowires of TiO2 and poly(2-acrylamido-2-methylpropane sulfonate) (TiO2 NWs/PAMPS) composite material films coated on quartz crystal microbalance (QCM) was prepared as a low humidity sensor. The 50 wt.% of TiO2 NWs/PAMPS composite material films showed excellent sensitivity (2.63 −ΔHz/Δppmv) at 31.5 ppmv), linearity (R2 = 0.9959) and acceptable response time (64 s at 34.6 ppmv). The low humidity sensing mechanism was discussed in terms of surface texture and nanostructured morphology of the composite materials. Moreover, the adsorption dynamic analysis, molecular mechanics calculation (association constant), was used to elucidate the effect of adding 50 wt.% TiO2 NWs into PAMPS in the increased sensitivity of low humidity sensing.