High sensitivity polyacrylic acid films for ammonia detection with field effect devices

Thin polyacrylic acid (PAA) films, with defined geometry, have been produced by spray deposition from dilute polymer solutions on metal plated wafers. The layer morphology was characterized by standard methods: optical, atomic force and scanning electron microscopy; stylus and optical profiler. Their sensing properties toward ammonia as target gas and the related cross sensitivities towards the most relevant interferents have been determined by the Kelvin Probe (KP) technique. The influence of the deposition parameters, layer thickness, operating temperature and aging were also investigated. The study was made in order to investigate the potential of PAA as sensing material for room temperature field effect gas sensors.