RESEARCH ARTICLE

Spatio-temporal control of the phase separation of chemically active immotile colloids

¹ School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
² Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
³ School of Physics and Astronomy, Institute of Natural Sciences and MOE-LSC, Shanghai Jiao Tong University, Shanghai 200240, China
⁴ School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
⁵ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

^* Corresponding authors (emails: weiwangsz@hit.edu.cn (Wei Wang); mcyang@iphy.ac.cn (Mingcheng Yang); hepengzhang@sjtu.edu.cn (Hepeng Zhang))

Received: 13 August 2023
Revised: 27 September 2023
Accepted: 20 October 2023

Abstract

Understanding and controlling phase separation in nonequilibrium colloidal systems are of both fundamental and applied importance. In this article, we investigate the spatiotemporal control of phase separation in chemically active immotile colloids. We show that a population of silver colloids can spontaneously phase separate into dense clusters in hydrogen peroxide (H₂O₂) due to phoretic attraction. The characteristic length of the formed pattern was quantified and monitored over time, revealing a growth and coarsening phase with different growth kinetics. By tuning the trigger frequency of light, the lengths and growth kinetics of the clusters formed by silver colloids in H₂O₂ can be controlled. In addition, structured light was used to precisely control the shape, size, and contour of the phase-separated patterns. This study provides insight into the microscopic details of the phase separation of chemically active colloids induced by phoretic attraction, and presents a generic strategy for controlling the spatiotemporal evolution of the resulting mesoscopic patterns.