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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 43: Wetting, Fluidics and Liquids at Interfaces and Surfaces (joint session CPP/DY)

CPP 43.3: Talk

Thursday, March 21, 2024, 15:30–15:45, H 0107

Surface Sensitive Fractioning of Microparticles and Microplastics — •Marek Bekir — Institut für Physik und Astronomie, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm

Separation of particles of equal size but different surface energies is nowadays a challenging task. With local-light driven diffusioosmosis (local-LDDO) [1] in combination with microfluidic technology [2] we provide a potential tool for separation of such microparticles and microplastics. The local-LDDO is a phenomenon of a photosensitive azo-benzene containing surfactant, where under illumination a dynamic exchange of isomers provides a repulsive flow strong enough to elevate particles up to several micrometers from the liquid-glass interface of the microfluidic chamber. In combination of a superimposed lamellar fluid flow the elevation leads to a stronger passive motion along the streamline. We demonstrate that the lift off depends on the size but also on the surface morphology, surface material and surface coating, too, i.e. differently surface modified particles therefore a different motion velocity.[3]

[1] Feldmann, D.; Arya, P.; Molotilin, TY.; Lomadze, N.; Kopyshev, A.; Vinogradova, OI.; Santer, S. Langmuir 2020, 36, 6994-7004.

[2] Sajeesh, P.; Kumar Sen, A. Microfluid Nanofluid 2014, 17, 1-52.

[3] Bekir, M.; Sperling, M.; Vasquez Muñoz, D., Braksch, C.; Böker, A.; Lomadze, N.; Popescu, M. N., Santer, S. Advanced Materials 2023, 35, 2300358.

Keywords: Particle Separation; Surface Sensitive Separation; Lightresponsive Surfactants; Microfluidics