Active string fluids and gels formed by dipolar active Brownian particles in 3D

Fuente: arXiv
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Hauptverfasser: Kelidou, Maria, Fazelzadeh, Mohammad, Parage, Baptiste, Farouji, Sara Jabbari
Format: Preprint
Veröffentlicht: 2024
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author Kelidou, Maria
Fazelzadeh, Mohammad
Parage, Baptiste
Farouji, Sara Jabbari
author_facet Kelidou, Maria
Fazelzadeh, Mohammad
Parage, Baptiste
Farouji, Sara Jabbari
contents Self-propelled particles possessing permanent magnetic dipole moments occur naturally in magnetotactic bacteria and in man-made systems like active colloids or micro-robots. Yet, the interplay between self-propulsion and anisotropic dipole-dipole interactions on dynamic self-assembly in three dimensions (3D) remains poorly understood. We conduct Brownian dynamics simulations of active dipolar particles in 3D, focusing on the low-density regime, where dipolar hard spheres tend to form chain-like aggregates and percolated networks with increasing dipolar coupling strength. We find that strong active forces override dipolar attractions, effectively inhibiting chain-like aggregation and network formation. Conversely, activating particles with low to moderate forces results in a fluid composed of active chains and rings. At strong dipolar coupling strengths, this active fluid transitions into an active gel, consisting of a percolated network of active chains. Although the overall structure of the active gel remains interconnected, the network experiences more frequent configurational rearrangements due to the reduced bond lifetime of active dipolar particles. Consequently, particles exhibit enhanced translational and rotational diffusion within the active fluid of strings and active gels compared to their passive counterparts. We quantify the influence of activity on aggregates topology, as they transition from branched structures to unconnected chains and rings. Our findings are summarized in a state diagram, delineating the impact of dipolar coupling strength and active force magnitude on the system.
format Preprint
id arxiv_https___arxiv_org_abs_2404_09693
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Active string fluids and gels formed by dipolar active Brownian particles in 3D
Kelidou, Maria
Fazelzadeh, Mohammad
Parage, Baptiste
Farouji, Sara Jabbari
Soft Condensed Matter
Self-propelled particles possessing permanent magnetic dipole moments occur naturally in magnetotactic bacteria and in man-made systems like active colloids or micro-robots. Yet, the interplay between self-propulsion and anisotropic dipole-dipole interactions on dynamic self-assembly in three dimensions (3D) remains poorly understood. We conduct Brownian dynamics simulations of active dipolar particles in 3D, focusing on the low-density regime, where dipolar hard spheres tend to form chain-like aggregates and percolated networks with increasing dipolar coupling strength. We find that strong active forces override dipolar attractions, effectively inhibiting chain-like aggregation and network formation. Conversely, activating particles with low to moderate forces results in a fluid composed of active chains and rings. At strong dipolar coupling strengths, this active fluid transitions into an active gel, consisting of a percolated network of active chains. Although the overall structure of the active gel remains interconnected, the network experiences more frequent configurational rearrangements due to the reduced bond lifetime of active dipolar particles. Consequently, particles exhibit enhanced translational and rotational diffusion within the active fluid of strings and active gels compared to their passive counterparts. We quantify the influence of activity on aggregates topology, as they transition from branched structures to unconnected chains and rings. Our findings are summarized in a state diagram, delineating the impact of dipolar coupling strength and active force magnitude on the system.
title Active string fluids and gels formed by dipolar active Brownian particles in 3D
topic Soft Condensed Matter
url https://arxiv.org/abs/2404.09693