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arXiv · 1202.6264

Dynamic clustering in active colloidal suspensions with chemical signaling

I. Theurkauff·C. Cottin-Bizonne·J. Palacci·C. Ybert·L. Bocquet
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Abstract

In this paper, we explore experimentally the phase behavior of a dense active suspension of self- propelled colloids. In addition to a solid-like and a gas-like phase observed for high and low densities, a novel cluster phase is reported at intermediate densities. This takes the form of a stationary assembly of dense aggregates, with an average size which grows with activity as a linear function of the self-propelling velocity. While different possible scenarii can be considered to account for these observations - such as a generic velocity weakening instability recently put forward -, we show that the experimental results are reproduced by a chemotactic aggregation mechanism, originally introduced to account for bacterial aggregation, and accounting here for diffusiophoretic chemical interaction between colloidal swimmers.

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I. Theurkauff, C. Cottin-Bizonne, J. Palacci, C. Ybert, L. Bocquet. 2012-02-28. Dynamic clustering in active colloidal suspensions with chemical signaling. https://doi.org/10.1103/physrevlett.108.268303

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