Dresden 2017 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 41: Active Matter II (joint session DY/BP/CPP)

DY 41.6: Vortrag

Donnerstag, 23. März 2017, 11:00–11:15, HÜL 186

Effective interactions between catalytic particle and fluid-fluid interfaces — •Paolo Malgaretti, Mihail Nicolae Popescu, and Siegfried Dietrich — Max Planck Institute for Intelligent Systems, Heisenbergstr. 3 70569 Stuttgart Germany

When catalytic particles, such as Janus particles, or enzymes are in the vicinity of a fluid-fluid interface, their is strongly modulated by the pres-ence of the interface and/or by the inhomogeneity in the transport properties of the two fluid phases. Hence, the effective interaction with the interface can lead to novel dynamical regimes absent in homogeneous fluids. For example, if the by-products of the catalysis are surfactants their spatial distribution will affect the local value of the surface tension. In such a scenario, when catalytic particles approache a fluid-fluid interface a Marangoni flow will set up in response to the inhomogeneity in the surface tension induced by the byproducts of the catalysis. The onset of such a flow attracts the catalytic particle towards the interface. Interestingly the strength of such an effective attraction is strongly affected by the affinity of the byproduct to the interface as well as by the transport properties of the two fluid phases. In particular, for water-oil interfaces such an effect overwhelms other means of active transport such as self-diffusiophoresis and makes it suitable to enhance particle accumulation close to fluid-fluid interfaces. Finally I will discuss the onset of collective behavior.