Diffusion of a chemically active colloidal particle in composite channels. (1st April 2022)

• Record Type: Journal Article
• Authors: Lou 娄, Xin 辛; Liu 刘, Rui 锐; Chen 陈, Ke 科; Zhou 周, Xin 昕; Podgornik, Rudolf; Yang 杨, Mingcheng 明成
• Is Part Of: Chinese physics B. Volume 31:Number 4(2022)
• Publication Date: 2022-04-01
• Subjects: diffusion -- composite channels -- diffusio-osmotic flow -- hydrodynamic effect; 47.57.-s -- 66.10.cd -- 02.70.Ns; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1674-1056/ac381b
• Languages: English
• ISSNs: 1674-1056

Abstract

Abstract : Diffusion of colloidal particles in microchannels has been extensively investigated, where the channel wall is either a no-slip or a slip-passive boundary. However, in the context of active fluids, driving boundary walls are ubiquitous and are expected to have a substantial effect on the particle dynamics. By mesoscale simulations, we study the diffusion of a chemically active colloidal particle in composite channels, which are constructed by alternately arranging the no-slip and diffusio-osmotic boundary walls. In this case, the chemical reaction catalyzed by the active colloidal particle creates a local chemical gradient along the channel wall, which drives a diffusio-osmotic flow parallel to the wall. We show that the diffusio-osmotic flow can significantly change the spatial distribution and diffusion dynamics of the colloidal particle in the composite channels. By modulating the surface properties of the channel wall, we can achieve different patterns of colloidal position distribution. The findings thus propose a novel possibility to manipulate colloidal diffusion in microfluidics, and highlight the importance of driving boundary walls in dynamics of colloidal particles in microchannels.