Effect of anisotropy on the formation of active particle films

Rebocho, T.C., Tasinkevych, M. ORCID: 0000-0001-6689-1844 and Dias, C.S., 2022. Effect of anisotropy on the formation of active particle films. Physical Review E, 106 (2): 024609. ISSN 2470-0045


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Active colloids belong to a class of non-equilibrium systems where energy uptake, conversion and dissipation occurs at the level of individual colloidal particles, which can lead to particles' self-propelled motion and surprising collective behaviour. Examples include coexistence of vapour-and liquid-like steady states for active particles with repulsive interactions only, phenomena known as motility induced phase transition. Similarly to motile unicellular organisms, active colloids tend to accumulate at confining surfaces forming dense adsorbed films. In this work, we study the structure and dynamics of aggregates of self-propelled particle near confining solid surfaces, focusing on the effects of the particle anisotropic interactions. We performed Langevin dynamics simulations of two complementary models for active particles: ellipsoidal particles interacting through Gay-Berne potential, and rod-like particles composed of several repulsive Lennard-Jones beads. We observe a non-monotonic behavior of the structure of clusters formed along the confining surface as a function of the particle aspect ratio, with a film spreading when particles are near spherical, compact clusters with hedgehog-like particle orientation for more elongated active particles, and a complex dynamical behavior for intermediate aspect ratio. The stabilization time of cluster formation along the confining surface also displays a non-monotonic dependence on the aspect ratio, with a local minimum at intermediate values. Additionally, we demonstrate that the hedgehog-like aggregates formed by Gay-Berne ellipsoids exhibit higher structural stability as compared to the ones formed by purely repulsive active rods, which are stable due to the particle activity only.

Item Type: Journal article
Publication Title: Physical Review E
Creators: Rebocho, T.C., Tasinkevych, M. and Dias, C.S.
Publisher: American Physical Society
Date: 25 August 2022
Volume: 106
Number: 2
ISSN: 2470-0045
Rights: ©2022 American Physical Society
Divisions: Schools > School of Science and Technology
Record created by: Jonathan Gallacher
Date Added: 11 Oct 2022 10:22
Last Modified: 11 Oct 2022 10:22
URI: https://irep.ntu.ac.uk/id/eprint/47238

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