RAMAN-SPECTROSCOPIC INVESTIGATION OF THE DISSOCIATION OF DIMETHYLSULFOXIDE INDUCED BY POLYACRYLONITRILE

The complex species of dimethylsulphoxide (DMSO) containing various am ounts of polyacrylonitrile (PAN) have been studied by Raman spectrosco py. By systematically studying the Raman spectra of the C=O stretching region, it has been found that the addition of PAN to DMSO breaks dow n the linear dimer and/or higher polymer, leading to the dissociation of DMSO molecules. It seems that the cyclic dimers of self-associated DMSO molecules are less affected by the introduction of PAN. Although the spectral changes of PAN are not as obvious as those of DMSO, it ca n still be seen that the scattering cross-section of the C=N stretchin g mode decreases above a PAN molar ratio of 0.8. It seems that DMSO an d PAN interact through the dipoles of their respective S=O and C=N gro ups, which makes DMSO a suitable plasticizer in PAN-based electrolytes .