Chemical interaction of gaseous ammonia and water vapour with polyacrylic acid layers

The sorption of water vapour and gaseous ammonia into polyacrylic acid (PAA) induces a mass uptake and changes the electrochemical properties of the material. In order to review and confirm phenomenological models describing these processes, systematic infrared (IR) studies have been performed. The IR spectra are taken in the 400–4000 cm−1 wavenumber range and the IR spectrum of the polymer in dry air is taken as the reference for calculation of the absorbance spectra. The interpretation of increasing and decreasing bands in the IR spectra draws a consistent picture of the processes in the polymer, so that the models can be confirmed and, additionally, more detailed information is gained.