Anti-Hofmeister series properties found for a polymer having a φ electron system and acidic protons

Anti-Hofmeister series properties have been found for a polymer (PVA-T) having a φ electron system and acidic protons, which were prepared by introducing trimellitic anhydride to poly(vinyl alcohol) (PVA). Aqueous dispersion of PVA-T became clear in the presence of 1 M Na₂SO₄, a typical kosmotrope, due to dissolution of the solid polymer sample, while the turbidity in the presence of 1 M KSCN, a typical chaotrope, hardly changed. Being consistent to the salt effects, PVA-T hydrogel, which was prepared by chemical cross-linking, showed marked swelling in sulfate solutions, whereas the swelling degree was only marginal in thiocyanates.