Phase separation of chemokinetic active particles

Abstract Motility-induced phase separation (MIPS) is a well-studied nonequilibrium collective phenomenon observed in active particles. Recently, there has been growing interest in how coupling the self-propulsion of active particles to chemical degrees of freedom affects MIPS. Although the effects o...

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Main Authors: Euijoon Kwon, Yongjae Oh, Yongjoo Baek
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Communications Physics
Online Access:https://doi.org/10.1038/s42005-025-02211-0
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author Euijoon Kwon
Yongjae Oh
Yongjoo Baek
author_facet Euijoon Kwon
Yongjae Oh
Yongjoo Baek
author_sort Euijoon Kwon
collection DOAJ
description Abstract Motility-induced phase separation (MIPS) is a well-studied nonequilibrium collective phenomenon observed in active particles. Recently, there has been growing interest in how coupling the self-propulsion of active particles to chemical degrees of freedom affects MIPS. Although the effects of chemotaxis on MIPS have been extensively studied, little is known about how chemokinesis affects MIPS. In this study, we demonstrate that various patterns can be induced when active particles consume chemicals and exhibit chemokinesis, where higher chemical concentrations enhance self-propulsion without causing alignment with the chemical gradient. We discover that MIPS is intensified if chemical consumption is proportional to particle density (as in the basal metabolic regime), but it is suppressed if chemical consumption is closely tied to particle motion (as in the active metabolic regime). While the former produces large-scale phase separation via coarsening, the latter suppresses the coarsening process, leading to microphase separation and oscillating patterns. We also derive a hydrodynamic theory that describes these findings.
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spelling doaj-art-75e7c6aff7174e9495b42b694fc97c972025-08-20T03:05:03ZengNature PortfolioCommunications Physics2399-36502025-07-018111110.1038/s42005-025-02211-0Phase separation of chemokinetic active particlesEuijoon Kwon0Yongjae Oh1Yongjoo Baek2Department of Physics and Astronomy & Center for Theoretical Physics, Seoul National UniversityDepartment of Physics and Astronomy & Center for Theoretical Physics, Seoul National UniversityDepartment of Physics and Astronomy & Center for Theoretical Physics, Seoul National UniversityAbstract Motility-induced phase separation (MIPS) is a well-studied nonequilibrium collective phenomenon observed in active particles. Recently, there has been growing interest in how coupling the self-propulsion of active particles to chemical degrees of freedom affects MIPS. Although the effects of chemotaxis on MIPS have been extensively studied, little is known about how chemokinesis affects MIPS. In this study, we demonstrate that various patterns can be induced when active particles consume chemicals and exhibit chemokinesis, where higher chemical concentrations enhance self-propulsion without causing alignment with the chemical gradient. We discover that MIPS is intensified if chemical consumption is proportional to particle density (as in the basal metabolic regime), but it is suppressed if chemical consumption is closely tied to particle motion (as in the active metabolic regime). While the former produces large-scale phase separation via coarsening, the latter suppresses the coarsening process, leading to microphase separation and oscillating patterns. We also derive a hydrodynamic theory that describes these findings.https://doi.org/10.1038/s42005-025-02211-0
spellingShingle Euijoon Kwon
Yongjae Oh
Yongjoo Baek
Phase separation of chemokinetic active particles
Communications Physics
title Phase separation of chemokinetic active particles
title_full Phase separation of chemokinetic active particles
title_fullStr Phase separation of chemokinetic active particles
title_full_unstemmed Phase separation of chemokinetic active particles
title_short Phase separation of chemokinetic active particles
title_sort phase separation of chemokinetic active particles
url https://doi.org/10.1038/s42005-025-02211-0
work_keys_str_mv AT euijoonkwon phaseseparationofchemokineticactiveparticles
AT yongjaeoh phaseseparationofchemokineticactiveparticles
AT yongjoobaek phaseseparationofchemokineticactiveparticles