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Coarse-graining hydro-phoretic interactions between active colloids

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mahdieh.ebrahimi@pkm.tu-darmstadt.de

aritra.mukhopadhyay@pkm.tu-darmstadt.de

benno.liebchen@pkm.tu-darmstadt.de

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Aritra K. Mukhopadhyay, Mahdieh Ebrahimi, Benno Liebchen.

Institut für Physik kondensierter Materie, Technische Universität Darmstadt, Germany.

Detailed fine-grained simulation model

Introduction

Interaction between two Janus particles

[1] A. Zöttl and H. Stark, J. Phys.: Condens. Matter 28, 253001 (2016).

[2] B. Liebchen and A. K. Mukhopadhyay, J. Phys.: Condens. Matter 34, 083002 (2022).

[3] K. Feng, J.C.U. Marcos, A. K. Mukhopadhyay, R. Niu, Q. Zhao, J. Qu, B. Liebchen, Advanced Science 10, 2300866 (2023).

[4] J. Palacci et al., Science 339, 936 (2013).

[5] I. Buttinoni et al., Phys. Rev. Lett. 110, 238301 (2013).

Acknowledgments

• Collective behaviors in active particles, such as Dictyostelium cell aggregation and Janus colloid clustering, arise from hydrodynamic, phoretic, and osmotic interactions [1,2].

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• Simulating and understanding these many-body interactions in large systems is a challenging task, especially with full hydrodynamic and phoretic effects.

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• In this project, we first perform detailed simulations of active colloids to characterize these interactions. We then use these fine-grained simulations to coarse-grain the dynamics of the active colloids and derive an analytical expression of their velocity based on inter-particle distances and orientations.

• This simulation framework offers detailed insights into phoretic and hydrodynamic field evolution and we have used it to study the dynamics of other active particles, including Marangoni flow-driven active droplets (left panel) [3].