2024/03/04 by Pragya Kushwaha, Sayan Maity, Kushwaha, Pragya +7
Engineering · Environmental Science · Physics and Astronomy · #Ecosystem dynamics and resilience #FOS: Physical sciences #Field-Flow Fractionation Techniques #Micro and Nano Robotics #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2403.02423
openalex publication_date 2024/03/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The growing interest in the non-equilibrium assembly of colloidal particles in active liquids is driven by the motivation to create novel structures endowed with tunable properties unattainable within the confines of equilibrium systems. Here, we present an experimental investigation of the structural features of colloidal assemblies in active liquids of chiral E. coli. The colloidal particles form dynamic clusters due to the effective interaction mediated by active media. The activity and chirality of the swimmers strongly influence the dynamics and local ordering of colloidal particles, resulting in clusters with persistent rotation, whose structure differs significantly from those in equilibrium systems with attractive interactions, such as colloid-polymer mixtures. The colloid-bacteria mixture displays several hallmark features of a percolation transition at a critical density, where the clusters span the system size. However, a closer examination of the critical exponents associated with cluster size distribution, average cluster size, and correlation length in the vicinity of the critical density suggest strong deviations from the prediction of the standard continuum percolation model. Therefore, our experiments reveal a richer phase behavior of colloidal assemblies in active liquids.