Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

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

DY 41.10: Talk

Thursday, March 23, 2017, 12:15–12:30, HÜL 186

Collective Effects of Active Particles at Fluid-Fluid Interfaces. — •Irina Kistner, Paolo Malgaretti, Mihail Nicolae Popescu, and Siegfried Dietrich — Max-Planck-Institut fuer Intelligente Systeme, Stuttgart, Germany

Micrometer sized particles capable of self-induced motility are of high interest for various applications in medicine, sensing and environmental science. Recent works report of different types of collective motion such as clustering, swarming or fluid-solid phase separation. Moreover different phenomena may arise when active particles are bounded or reside in the proximity of a fluid-fluid interface [1], [2].

The model system we are investigating consists of two or more chemically active, spherical colloidal particles located close to a fluid-fluid interface. Due to the Marangoni stresses self-induced at the interface, the particles experience a repulsive long-ranged effective force field under harmonic confinement. We show that this effective interaction results in a crystal-like pattern formation of collectively rotating particles and define a gas-crystal phase separation governed by the Marangoni force constant.

[1] A. Dominguez, P. Malgaretti, M. N. Popescu, and S. Dietrich: Effective interaction between active colloids and fluid interfaces induced by Marangoni flows, Phys. Rev. Lett. 117, 079902 (2016)

[2] A. Dominguez, P. Malgaretti, M. N. Popescu, and S. Dietrich: Collective dynamics of chemically active particles trapped at a fluid interface, Soft Matter, 12, 8398-8406 (2016)