SKM 2023 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 53: Charged Soft Matter, Polyelectrolytes and Ionic Liquid

CPP 53.2: Vortrag

Donnerstag, 30. März 2023, 15:30–15:45, ZEU 255

Why weakly hydrated anions bind to polymers but not to monomers? — Bradley A. Rogers¹, Halil I. Okur^1,4, Chuanyu Yan¹, Tinglu Yang¹, •Jan Heyda², and Paul S. Cremer^1,3 — ¹Department of Chemistry, The Pennsylvania State University, University Park, PA, USA. — ²Department of Physical Chemistry, University of Chemistry and Technology, Prague, Dejvice, Czech Republic. — ³Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA. — ⁴Present address: Department of Chemistry and National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey.

Weakly hydrated anions help to solubilize hydrophobic macromolecules in aqueous solutions, but small molecules comprising the same chemical constituents precipitate out when exposed to these ions. Here, this apparent contradiction is resolved by systematically investigating the interactions of NaSCN with polyethylene oxide oligomers and polymers of varying molecular weight. A combination of spectroscopic and computational results reveals that SCN- accumulates near the surface of polymers, but is excluded from monomers. This occurs because SCN- preferentially binds to the centre of macromolecular chains, where the local water hydrogen-bonding network is disrupted. These findings suggest a link between ion-specific effects and theories addressing how hydrophobic hydration is modulated by the size and shape of a hydrophobic entity.