Complexation of chitosan with acetic acid according to Fourier transform Raman spectroscopy data

The results of the interaction between the protonated chitosan (CHI) macromolecule and the acetate ion in dilute acetic acid solutions were studied by Fourier transform Raman spectroscopy and quantum-chemical modeling. The complexation of CHI with the acetate ion showed itself as the 934 cm^?1 band in the Raman spectrum, which suggests the formation of CHI⁺ · CH₃COO^?] type ion pairs. It was concluded that a comparative analysis of the integrated intensities of the Raman bands in the range 880–940 cm^?1 makes it possible to judge about the relative content of hydrated acetate ions, CHI macromolecules of the CHI⁺ · CH₃COO^?] complex, and acetic acid molecules not involved in CHI protonation.