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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: Poster Session II - Complex Fluids and Perovskites

CPP 14.10: Poster

Tuesday, March 23, 2021, 16:30–18:30, CPPp

ToF-NR swelling study on metal coated PNIPAM microgel thin films using a 3D-printed environmental chamber — •Tobias Widmann¹, Lucas P. Kreuzer¹, Christina Geiger¹, Julian E. Heger¹, Gaetano Mangiapia², Thomas Hellweg³, and Peter Müller-Buschbaum¹ — ¹TU München, Physik Department, LS Funktionelle Materialien, 85748 Garching — ²HZG at MLZ, 85748 Garching — ³Universität Bielefeld, Chemie Department, Physikalische und Biophysikalische Chemie, 33615 Bielefeld

Thermoresponsive microgels typically show a strong change in volume upon crossing the volume phase transition temperature (VPTT). For LCST type polymers, such as for example microgels based on N-isopropylacrylamide (NIPAM) which has an LCST of 32 °C, these microgels are in a hydrophilic state below the VPTT. In that temperature regime, they are highly sensitive to humidity, which makes them interesting candidates for humidity sensing applications on the nanoscale. Therefore, we investigate thin films of PNIPAM microgels cross linked with N,N*-methylenebisacrylamide under cyclic high and low humidity conditions. We follow the swelling and drying processes in situ using time-of-flight neutron reflectometry (ToF-NR). For that purpose, we used a custom made 3D-printed environmental chamber that was designed and built in the framework of the FlexiProb project, which aims for a quickly interchangeable sample environment for experiments at the European spallation source (ESS).