English

Phase separation of passive particles in active liquids

Soft Condensed Matter 2023-01-30 v1

Abstract

The transport properties of colloidal particles in active liquids have been studied extensively. It has led to a deeper understanding of the interactions between passive and active particles. However, the phase behavior of colloidal particles in active media has received little attention. Here, we present a combined experimental and numerical investigation of passive colloids dispersed in suspensions of active particles. Our study reveals dynamic clustering of colloids in active media due to an interplay of active noise and an attractive effective potential between the colloids. The size-ratio of colloidal particles to the bacteria sets the strength of the interaction. As the relative size of the colloids increases, the effective potential becomes stronger and the average size of the clusters grows. The simulations reveal a macroscopic phase separation of passive colloids at sufficiently large size-ratios. We will present the role of density fluctuations and hydrodynamic interactions in the emergence of effective interactions.

Keywords

Cite

@article{arxiv.2301.11771,
  title  = {Phase separation of passive particles in active liquids},
  author = {Pragya Kushwaha and Vivek Semwal and Sayan Maity and Shraddha Mishra and Vijayakumar Chikkadi},
  journal= {arXiv preprint arXiv:2301.11771},
  year   = {2023}
}