Ion-Specific Morphological Evolution of Sulfone-Functionalized Dipolar Polymersomes

Micelles exhibit distinct ion-specific effects depending on the polarity of their cores. Herein, we systematically investigate the specific ion effects on sulfone-functionalized polymersomes, revealing distinct ion-specific responses in nonionic micellar systems with polar cores. The influence of a series of Hofmeister salts on the colloidal stability and morphological evolution of poly(N,N-dimethyl acrylamide)-b-poly[2-(propylsulfonyl)ethyl acrylamide] (PDMAc-b-PPSEAm) polymersomes was studied. While the polymersomes show minimal cation sensitivity, they exhibit pronounced anion-specific responses correlating with anion hydration ability. Chaotropic anions drive morphological evolution toward wormlike micelles and spherical micelles by binding directly to the core-forming block and altering its hydrophilicity, with efficacy following the Hofmeister series: I^- > SCN^- > Br^- > NO₃^- > Cl^-. Conversely, kosmotropic anions induce precipitation of polymersomes via dehydration of the corona-forming block, with efficacy ranking as CO₃^2- ≈ SO₄^2- > H₂PO₄^-.