Berlin 2024 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster I

CPP 15.38: Poster

Monday, March 18, 2024, 18:00–20:00, Poster C

PNIPAM microgel-stabilized aqueous Pickering foams — •Joanne Zimmer, Gaëtan Barth, Luca Mirau, and Regine von Klitzing — Technische Universität Darmstadt, Department of Physics, Soft Matter at Interfaces, Hochschulstraße 8, 64289 Darmstadt

Particle-stabilized foams (Pickering foams) are gaining increasing attention due to their high long-term stability and possible stimuli-responsiveness. Suitable stabilizers for generation of these foams are PNIPAM microgels (MG) as they possess a high adsorption energy at the water-air-interface compared to classical surfactants. In addition, they show a temperature-dependent reversible volume phase transition which allows for generation of switchable foams, that can be destroyed on demand.

In this work MG stabilized Pickering foams were generated by sparging gas through a PNIPAM MG dispersion. For this purpose, the Teclis Foam Scan device is used, which measures foam properties like foam volume over time, liquid fraction and bubble size and bubble size distribution. A special focus was set on identifying device and sample parameters for generation of foams with a homogenous bubble size distribution. This is essential for a quantitative comparison of the foam properties and investigation of foam destabilization processes. In addition, it must be noticed, that addition of NaCl to the MG dispersion is required to increase the electrical conductivity and allow for determination of the foam liquid content. Thus, the influence of the NaCl concentration on the foaming properties was also subject of this study.

Keywords: PNIPAM microgel; foam; water-air-interface