2025/08/21 by Abhradeep Maitra, Maitra, Abhradeep, Anupam Pandey +5 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Active matter #Advanced Materials and Mechanics #Atomic packing factor #Drag #FOS: Physical sciences #Magnetosphere particle motion #Marangoni effect #Micro and Nano Robotics #Particle (ecology) #Pickering emulsions and particle stabilization #Raft #Smoothed-particle hydrodynamics #Soft Condensed Matter (cond-mat.soft) #Towing
paper · pdf · doi:10.48550/arxiv.2508.15205
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2025/08/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Active matter systems, due to their spontaneous self-propulsion ability, hold potential for future applications in healthcare and environmental sustainability. Marangoni swimmers, a type of synthetic active matter, are a common model system for understanding the underlying physics. Existing studies of the interactions of active matter with passive particles have mostly focused on the modification of the behavior of the passive particles. In contrast, we analyse here experimentally the impact on the self-propulsion of camphor-infused agarose disks (active) of their interactions with floating hollow glass microspheres (passive) within an annular channel. Two distinct regimes are observed: a steady regime with uni-directional motion of the swimmer at low packing fractions (ϕ_\textrmini \lesssim 0.45) and an oscillatory regime with to-and-fro motion at higher packing fractions (ϕ_\textrmini \gtrsim 0.45). In the former, the swimmer pushes nearly the entire particle raft together with it, like a towing cargo, causing a decrease in swimmer speed with increasing packing fraction due to the additional drag from the particle raft. A simplified force-balance model is finally proposed that captures the experimental trend in swimmer speed reasonably well.