Sorption and perturbation of water at polyelectrolyte interfaces. Paper 5—effects of water isotopic dilution

We have carefully examined the possible role of local oscillator coupling in D2O(or H2O), and locally concentrated evanescent electric fields in creating a large intensity perturbation of the ν(OD) band of water in the polyelectrolytes SPEES/PES (S5, S8 and S20). Isotopic dilution experiments lead to the same (or higher) extinction coefficient while an ATR/transmission experimental comparison also gives a similar intensity. We conclude that neither effect is responsible for enhanced P values, and that these must be caused by strong polymer–water interactions at the anionic SO3− groups on these polymers.