Preferential adsorption behavior of poly(vinylpyrrolidone) in tetrahydrofuran-water mixtures

The preferential adsorption behavior of poly(vinylpyrrolidone) (PVP) and one alternating copolymer of vinylpyrrolidone-co-maleic acid (CP₁H) in the binary solvent mixture THF/water were studied. Water is preferentially adsorbed by PVP and THF by the copolymer at low THF compositions. Both systems show enhancement of the solubility and an inversion point in the preferential solvation. The results are discussed in terms of specific interactions between solvents and side chains of the polymers. The conformational arrangements of the side groups are considered.