Responsiveness of the first combination band of water to the state in organic and polymeric medium

We studied the influence of intermolecular interactions on the first combination band between the OH-stretching and -deformation vibrations of the water that is dissolved in organic and polymeric materials. The water has two types. The first type occurs in the matrix in which water-interactive functional groups are densely distributed. The water is symmetrically hydrogen-bonded through each OH to two functional groups and shows one clear combination band, of which the frequency depends on the strength of the hydrogen bond. The second type occurs in the matrix in which the functional groups are rarely distributed. One OH of this water is hydrogen-bonded to the functional group but the other OH is free. The water shows two combination bands, of which one is sharp and strong at about 5300 cm−1 and the other is weaker and broader, the frequency changing in the 5200-5100 cm−1 range. Thus, the dissolved water sensitively responds to the nature of a water-interactive functional group and its distribution density in a matrix, and shows the first combination band that is characteristic of these factors.