Enhanced sensitivity of polyphenylacetylene and poly[phenylacetylene-(co-2-hydroxyethyl methacrylate)] nanobeads to humidity

Humidity sensors based on nanobeads of conjugated polymers, i.e., polyphenylacetylene (PPA) and poly[phenylacetylene-(co-2-hydroxyethyI methacrylate] P(PA/HEMA), prepared by modified emulsion polymerization technique, have been developed using resistive type and quartz crystal microbalance (QCM) devices. The investigations on the electrical response of PPA and P(PA/HEMA) nanobeads were performed and resistive humidity sensors based on ordered arrays of these nanostructured polymeric materials showed fast and reproducible current intensity variations in the range of relative humidity RH 5 - 90%. Polymeric nanostructured films deposited on the quartz electrode of QCM showed a linear sensitivity of 0.024 Hz/ppmv and short response time.