Polymer–water interactions. Origin of perturbed infrared intensities of water in polymeric systems

We explore the possible reasons for the huge infrared intensity perturbations of water molecules sorbed onto a variety of polymer surfaces. We demonstrate that strong polymer–water interactions, not always obvious from qualitative approaches to examination of the water vibrational spectra, are probably responsible for such effects. The deviations from Beer’s law for water adsorption is semi-quantitatively correlated with the level of water uptake (i.e. water activity in the polymer). This clearly demonstrates the dependence on water–polymer proximity and intermolecular interaction strength, to the extent that donor–acceptor charge transfer interactions may well control this interesting, and potentially useful, phenomenon.