Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 36: Poster: (Hydro)gels and Elastomers
CPP 36.3: Poster
Mittwoch, 13. März 2013, 16:30–18:30, Poster C
Kinetics of aggregation in micellar solutions of thermoresponsive triblock copolymers: influence of concentration, start and target temperature — Joseph Adelsberger1, Amit Kulkarni1, Isabelle Grillo2, Melissa Sharp3, Achille M. Bivigou-Koumba4, André Laschewsky4, Peter Müler-Buschbaum1, and •Christine M. Papadakis1 — 1TU München, Physik-Department, Physik weicher Materie, Garching — 2Institut Laue-Langevin, Grenoble, France — 3European Spallation Source, Lund, Sweden — 4Uni Potsdam, Institut für Chemie, Potsdam-Golm
Micellar solutions of thermoresponsive block copolymers respond to a small change of temperature across the cloud point with a strong volume change. We have investigated triblock copolymers having a long poly(N-isopropylacrylamide) (PNIPAM) middle block and two short polystyrene (PS) end blocks. Temperature-resolved SANS with contrast matching revealed the collapse of the micellar shell and the subsequent aggregation [1]. Time-resolved SANS during a temperature jump showed that the process involves a number of steps, such as the formation of small imperfect aggregates, their densification and their growth by attachment of single micelles and finally by coagulation [2]. The time constants depend on polymer concentration, start and target temperature [2].
1. J. Adelsberger, C.M. Papadakis et al., Macromolecules 43, 2490 (2010) and Colloid Polym. Sci. 289, 711 (2011).
2. J. Adelsberger, C.M. Papadakis et al., Macromol. Rapid Commun. 33, 254 (2012) and Soft Matter, DOI:10.1039/C2SM27152D