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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 49: Gels, Polymer Networks and Elastomers I

CPP 49.5: Vortrag

Donnerstag, 12. März 2026, 12:30–12:45, ZEU/0255

Aqueous Foams stabilized by PNIPAM Microgels: Effect of Cross-linker and Concentration — •Joanne Zimmer, Kevin Gräff, Luca Mirau, and Regine von Klitzing — Soft Matter at Interfaces, Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, D-64289 Darmstadt

Aqueous foams are abundant in everyday life, important for industrial applications and interesting from a fundamental point of view. In this work, aqueous foams are generated by sparging gas (nitrogen) through an aqueous dispersion of PNIPAM microgels, which are used as foam stabilizers. The microgel cross-linker content as well as the microgel concentration are varied and prove to significantly influence the foam formation properties (foamability) and the foam stability. A lower cross-linker content as well as a higher microgel concentration elevate the foamability, generate foams with higher liquid content and smaller bubbles and increase the foam stability. These observations are correlated with the microgel behaviour at the single air-water interface, i.e. pendant drop measurements and Langmuir trough. Our findings highlight good agreement across both length scales: an increase in foamability correlates with a faster decrease in surface tension, and a higher foam stability with a higher surface elastic modulus of a microgel-covered single air-water interface. The ability of the microgels to form a collective polymer network seems to dominate these processes.

Keywords: Microgel; PNIPAM; Polymer network; Surface elasticity; Aqueous foam