2024/11/19 by Rahul Chand, Chand, Rahul, Ashutosh Shukla +5
Chemistry · Engineering · Physics and Astronomy · #Computational Physics (physics.comp-ph) #FOS: Physical sciences #Field-Flow Fractionation Techniques #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Micro and Nano Robotics #Molecular spectroscopy and chirality #Optics (physics.optics) #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2411.12488
openalex publication_date 2024/11/19 · openalex created_date 2024/11/21 · openalex updated_date 2026/08/01
Artificial soft matter systems have appeared as important tools to harness mechanical motion for microscale manipulation. Typically, this motion is driven either by the external fields or by mutual interaction between the colloids. In the latter scenario, dynamics arise from non-reciprocal interaction among colloids within a chemical environment. In contrast, we eliminate the need for a chemical environment by utilizing a large area of optical illumination to generate thermal fields. The resulting optothermal interactions introduce non-reciprocity to the system, enabling active motion of the colloidal structure. Our approach involves two types of colloids: passive and thermally active. The thermally active colloids contain absorbing elements that capture energy from the incident optical beam, creating localized thermal fields around them. In a suspension of these colloids, the thermal gradients generated drive nearby particles through attractive thermo-osmotic forces. We investigate the resulting dynamics, which lead to various swimming modes, including active propulsion and chiral motion. We have also experimentally validated certain simulated results. By exploring the interplay between optical forces, thermal effects, and particle interactions, we aim to gain insights into controlling colloidal behavior in non-equilibrium systems. This research has significant implications for directed self-assembly, microfluidic manipulation, and the study of active matter.