Dresden 2017 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 56: Hydrogels and Microgels I
CPP 56.7: Talk
Thursday, March 23, 2017, 12:15–12:30, ZEU 260
Structure and Dynamics of highly concentrated PNIPAm microgels. — •Lara Frenzel1,2, Felix Lehmkühler1,2, Michael Höltig1, and Gerhard Grübel1,2 — 1DESY, Hamburg, Germany — 2The Hamburg Centre for Ultrafast Imaging, CUI, Hamburg, Germany
Poly (N-isopropylacrylamide) (PNIPAm) is a stimuli responsive cross-linked microgel with a coil-to-globule transition at a lower critical solution temperature (LCST) in water around 32°C, which results in a rapid collapse of the particle radius by increasing the temperature. With this volume phase transition PNIPAm is both applicable in technical as well as medical fields. Furthermore, it became a frequently examined system in research such as a model to study the specific phase behavior of soft colloids. Via x-ray photon correlation spectroscopy (XPCS) we investigate the change in structure and dynamics of PNIPAm microgels at high concentrations around the LCST. Thereby highly brilliant x-rays from the coherence beamline P10 at PETRA III have been used in the XPCS study. Since the swollen microgel shows a low refractive index difference compared to water we studied both pure PNIPAm as well as silica-PNIPAm core-shell systems.