Berlin 2024 – scientific programme
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BP: Fachverband Biologische Physik
BP 26: Biopolymers, Biomaterials and Bioinspired Functional Materials (joint session CPP/BP)
BP 26.12: Talk
Thursday, March 21, 2024, 12:45–13:00, H 0111
Untangling the stabilizing effects of proteins as foaming agents — •Kevin Gräff1, Sebastian Stock1, Luca Mirau1, Sabine Bürger1, Larissa Braun1, Annika Völp2, Norbert Willenbacher2, and Regine von Klitzing1 — 1Soft Matter at Interfaces, Technische Universität Darmstadt, Darmstadt, Germany — 2Institute of Mechanical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Foams appear in many applications such as in personal care products, firefighting and food technology. Macroscopic foams consist of air bubbles separated by foam films. Therefore, it is crucial to untangle electrostatic, steric and network stabilization effects in foam films to understand macroscopic foam properties. We compare globular proteins (β - lactoglobulin and bovine serum albumin), a flexible protein (whole casein) and lupine protein isolate with varying solution pH. In a Thin Film Pressure Balance (TFPB) we use image intensity measurements to record spatially resolved disjoining pressure isotherms and to gain information about structure formation. We introduce feature tracking as a novel method to measure the interfacial mobility and stiffness of foam films. Around the isoelectric point, stable Newton Black Films (NBFs) for the globular proteins form in contrast to the unstable NBFs for the flexible proteins due to different characteristics of the network structures. To evaluate the foam films impact on macroscopic foams, we use a Bikerman cell to measure foam parameters (e.g. foamability). Small Angel Neutron Scattering (SANS) on macroscopic foams completes the picture.
Keywords: Foam stabilization; Foam Films; Proteins; Thin Film Pressure Balance; Small Angel Neutron Scattering