Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Hydrogels and Microgels
CPP 8.3: Vortrag
Montag, 7. März 2016, 15:45–16:00, H40
Cononsolvency in thermoresponsive micellar solutions: Pathway of aggregate formation — Konstantinos Kyriakos1, Anatoly V. Berezkin1, Martine Philipp1, Alessio Zaccone1, Isabelle Grillo2, Anna Miasnikova3, André Laschewsky3,4, Peter Müller-Buschbaum1, and •Christine M. Papadakis1 — 1Technische Universität München, Physik-Department, Garching, Germany — 2Institut Laue-Langevin, Grenoble, France — 3Universität Potsdam, Institut für Chemie, Germany — 4Fraunhofer Institut für Angewandte Polymerforschung, Potsdam-Golm, Germany
The switching kinetics of thermoresponsive polymers are of importance for many applications. In mixtures of water and a cosolvent, the cloud point may be reduced, which offers additional possibilities for switching.
We have investigated the switching kinetics of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) homopolymers and of micelle forming PS-b-PNIPAM (PS stands for polystyrene) diblock copolymers in two ways: (i) by addition of the cosolvent methanol to aqueous solutions of the two polymers [1] and (ii) by rapidly heating a PS-b-PNIPAM solution through the cloud point [2]. The aggregate growth was followed by time-resolved small-angle neutron scattering. The process is very different for PNIPAM and for PS-b-PNIPAM and depends sensitively on the pathway. We have developed theoretical models to relate the growth rate to the interaction between the collapsed micelles.
1.K. Kyriakos et al., Macromolecules 2014, 47, 6867
2.K. Kyriakos et al., Macromol. Rapid Commun., in press.