Berlin 2024 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster I

CPP 15.7: Poster

Montag, 18. März 2024, 18:00–20:00, Poster C

Probing the mechanical properties of core-shell-like PNIPAM microgels — •Manmeet Kaur Sodhi and Regine Von Klitzing — Technische Universität Darmstadt

Stimuli-responsive liquid foams have a huge impact in terms of both fundamental research and technical applications such as catalysis, food technology, waste, since they allow a foam rupture on demand triggered by external stimuli. Temperature responsive. PNIPAM microgels (radii in the range of several 100 nm) are well-known to stabilize foams, and they have a volume phase transition temperature (VPTT) of about 32^∘C, i.e. below this temperature water is a good solvent and the microgels are swollen. By crossing the VPTT water becomes a poor solvent and the microgels shrink, their stiffness controlled by the degree of crosslinking, and their ability to stabilize liquid foams. This study focuses on the fundamental question of how important the softness/stiffness of the microgels is to stabilize foams. To achieve this, the mechanical properties of negatively charged individual microgel particles at solid/air interface as well as solid water interface has been studied. The data is complemented with the dynamic light scattering which not only gives us the quantitative understanding of including their hydrodynamic radius and polydispersity but also allows us to understand the behaviour of these microgels at lower critical transition temperature.

Keywords: Atomic force microscopy; poly(N-isopropylacrylamide); microgels; Dynamic light scattering; Static light scattering