Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Hydrogels and Microgels
CPP 8.6: Vortrag
Montag, 7. März 2016, 16:45–17:00, H40
Swelling kinectics of N-n-propylacrylamide based microgels upon periodic pressure jumps investigated by time-resolved SANS — •Oliver Wrede1, Yvonne Pütz2, Stefan Lülsdorf3, Diana Zauser3, Yvonne Hertle1, Ralf Schweins4, Thomas Sottmann3, and Thomas Hellweg1 — 1Bielefeld University, Germany — 2University of Cologne, Germany — 3University of Stuttgart, Germany — 4Institut Laue-Langevin, France
Temperature responsive microgels are particles in the size range between 100 nm and 1 µm, that undergo a reversible microphase seperation at a certain temperature. Structure, size and phase transition properties can be controlled by the synthetis conditions. This makes them outstanding candidates for various applications, such as drug delivery, catalytic particle carriers or nanoactuators. A precise understanding of the underlying processes is necessary to allow to tune the network properties. Therefore, we investigated the swelling and deswelling kinetics of N-n-propylacrylamide based microgels upon periodic pressure jumps across the phase transition with different cross-linker contents by time-resolved SANS. Preceding DLS measurements showed, that the phase transition shifts towards higher temperatures with increasing pressure, i.e. a swelling of the particles is induced upon compression. Our findings show, that the time scale of the kinetics changes with cross-linker content by more than one order of magnitude, which confirmes the important role of the network morphology. Besides the influence of the cross linker, the kinetics of the swelling is considerably faster than the deswelling process.