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10–11 Dec 2019
Marriott
Europe/Berlin timezone

Cononsolvency in PNIPAM-based block copolymer thin films

11 Dec 2019, 13:30
3h
Marriott Conference room - Munich (Marriott)

Marriott Conference room - Munich

Marriott

Berliner Str. 93 80805 München Germany
300
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Board: 55
Poster Soft Matter Poster session

Speaker

Ms Christina Geiger (Technical University of Munich, Chair of Functional Materials, Garching)

Description

The diblock copolymer PMMA-b-PNIPAM forms micelles in aqueous solution that exhibit a reversible shell collapse transition at the lower critical solution temperature (LCST). This thermo-response can be moderated by introducing organic cosolvents such as methanol, ethanol or acetone. In thin film configuration, their multi-responsive behavior makes NIPAM-based polymers promising systems for vapor-sensitive nanosensors and actuators. We prepare thin films with a large PNIPAM block and perform swelling experiments in a custom chamber. The film response is probed for mixed vapors of different solvent and cosolvent content, while the temperature is held constant in order to purely probe the cononsolvency effect. Morphological changes, as well as the swelling kinetics related to the uptake of solvent and cosolvent into the film, concentration gradients and the development of swelling ratio and refractive index are investigated with a focus on spectroscopic reflectance (SR) and in-situ time-of-flight neutron reflectometry (TOF-NR). Running sequential experiments with protonated and deuterated compounds allows us to extract the individual distributions of solvent and cosolvent in the film by contrasting SLD profiles from static TOF-NR curves. SR can be used to monitor the film thickness in real time as well as to use as a feed parameter in batch fits of kinetic TOF-NR data. First results show that cononsolvency-related behavior is transferrable from solution to thin film systems.

Primary authors

Ms Christina Geiger (Technical University of Munich, Chair of Functional Materials, Garching) Mr Tobias Widmann (Technical University of Munich, Chair of Functional Materials, Garching) Mr Lucas Kreuzer (Technical University of Munich, Chair of Functional Materials, Garching) Mr Gaetano Mangiapia (Research Neutron Source Heinz Maier-Leibnitz (FRMII), Garching ) Ms Cristiane Henschel (University of Potsdam, Applied Polymer Chemistry Group, Potsdam-Golm) André Laschewsky (University of Potsdam, Applied Polymer Chemistry Group, Potsdam-Golm) Christine M. Papadakis (4Technical University of Munich, Soft Matter Physics Group, Garching) Peter Müller-Buschbaum (Technical University of Munich, Chair of Functional Materials, Garching)

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