Raman spectroscopic study of hydrogen bonding of poly(N-vinyl-2-pyrrolidone) in heavy water and dimethyl sulfoxide

The Raman spectra of solutions of poly(N-vinyl-2-pyrrolidone) (PVP; M?_w = 1 000, 10 000, 40 000 and 360 000) in D₂O and dimethyl sulfoxide (DMSO) were measured at various concentrations. PVP is hydrated by D₂O in a manner different from N-ethyl-2-pyrrolidone (NEP) and N-methyl-2-pyrrolidone (NMP), monomer analogues of PVP. The self-association of DMSO molecules in the solution of PVP was found to be different from that in the solution of NMP by using difference spectroscopy. These phenomena were attributed to a net-like structure of concentrated solutions of PVP.