Regensburg 2019 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 49: Hydrogel und Microgel

CPP 49.4: Talk

Wednesday, April 3, 2019, 18:15–18:30, H18

Non-additive ion effects on polymer coil-globule collapse transitions in mixed salt solutions — •Nico van der Vegt¹, Ellen E. Bruce¹, Pho T. Bui², Bradley A. Rogers², and Paul S. Cremer² — ¹Technische Universität Darmstadt, Germany — ²Pennsylvania State University, USA

Non-additive ion effects in Hofmeister ion chemistry impact properties of aqueous soft matter but are poorly understood to date. I will present ion-specific effects on the lower critical solution temperature of poly(N-isopropylacrylamide) in mixed electrolyte solutions. Significantly, I will show that polymer hydration and polymer-anion interactions can be regulated in the presence of weakly (NaI) and strongly hydrated (Na2SO4) mixed salts, leading to both collapse and swelling of the polymer. The underlying mechanisms are discussed based on insights obtained from computer simulations and vibrational sum frequency spectroscopy (VSFG) experiments.