Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 11: POSTERS Amphiphilic Systems
CPP 11.3: Poster
Dienstag, 24. März 2009, 14:00–16:30, P3
Structure, dynamics and kinetics of thermoresponsive blockcopolymer gels — •Joseph Adelsberger1, Andreas Meier-Koll1, Weinan Wang1, Thomas Hellweg2, Achille M. Bivigou Koumba3, André Laschewsky3, Peter Müller-Buschbaum1, and Christine M. Papadakis1 — 1TU München, Physik-Department E13, Garching — 2Universität Bayreuth, Physikalische Chemie I — 3Universität Potsdam, Institut für Chemie
Thermoresponsive polymer gels display strong changes in volume when heated above the lower critical solution temperature (LCST). We investigate triblock copolymers consisting of two hydrophobic polystyrene (PS) end blocks and a hydrophilic poly-(N-isopropyl-acrylamide) (PNIPAM) middle block. In aqueous solution they form core-shell-micelles or micellar networks. The structure of the micelles and their correlation is determined using SANS and dynamic light scattering [1]. The micellar radius shows a sudden decrease at the LCST. Above the LCST the collapsed micelles form clusters. Water is released and the formerly hydrophilic shell shrinks. The results are compared to the ones of diblock copolymers [2]. Neutron spin-echo spectroscopy is used to study the segmental dynamics of the hydrophilic block. Below the LCST the averaged diffusion coefficient of the PNIPAM block is unchanged. Time resolved SANS allowed us to investigate the kinetics of structural changes induced by fast heating above the LCST.
[1] A. Jain, C. M. Papadakis et al., Macromol. Symp., submitted
[2] K. Troll, C. M. Papadakis et al., Colloid Polym. Sci., 286 (2008), 1079-1092