Dresden 2017 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 52: Poster: Hydogels, Microgels, Responsive Polymers
CPP 52.6: Poster
Wednesday, March 22, 2017, 18:30–21:00, P3
Aggregation behavior of PNIPAM in dependence on temperature and pressure — •Bart-Jan Niebuur1, Kora-Lee Claude1, Simon Pinzek1, Konstantinos N. Raftopoulos1, Vitaliy Pipich2, Marie-Sousai Appavou2, Alfons Schulte3, and Christine M. Papadakis1 — 1Technische Universität München, Physik-Department, Fachgebiet Physik weicher Materie, Garching, Germany — 2Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Garching, Germany — 3University of Central Florida, Department of Physics and College of Optics & Photonics, Orlando, U.S.A.
The phase separation mechanism of poly(N-isopropylacrylamide) (PNIPAM) is still under debate. Instead of phase separating macroscopically, PNIPAM forms stable mesoglobules in the two-phase region at atmospheric pressure in aqueous solutions. We have investigated the phase behavior in dependence on temperature and pressure using turbidimetry. The aggregates in the two-phase region are characterized using very small-angle neutron scattering, optical microscopy and Raman spectroscopy. At high pressure, the aggregates are larger than at atmospheric pressure. A possible reason is the decreased efficiency of the phase separation at high pressure because the chains stay hydrated even in the two-phase region. Thus, inducing the phase transition by applying high pressure and by combining a variety of methods, the nature of the transition can be related to the mesoscopic domain structure in the two-phase state.