# Orientational order and morphology of clusters of self-assembled Janus swimmers

## TL;DR

This study investigates how anisotropic interactions and activity influence the self-assembly and morphology of Janus swimmer clusters, revealing diverse aggregation behaviors in semi-dilute suspensions with tunable propulsion directions.

## Contribution

It introduces a systematic analysis of how anisotropic interactions and activity directionality affect cluster formation in Janus swimmers, advancing understanding of active material self-assembly.

## Key findings

- Anisotropic interactions and activity directionality lead to diverse aggregation patterns.
- Tuning hydrophobic strength influences cluster morphology.
- Active stress competes with attractive interactions to determine structures.

## Abstract

Due to the combined effect of anisotropic interactions and activity, Janus swimmers are capable to self-assemble in a wide variety of structures, many more than their equilibrium counterpart. This might lead to the development of novel active materials capable of performing tasks without any central control. Their potential application in designing such materials endows trying to understand the fundamental mechanism in which these swimmers self-assemble. In the present work, we study a quasi-two dimensional semi-dilute suspensions of two classes of amphiphilic spherical swimmers whose direction of motion can be tuned: either swimmers propelling in the direction of the hydrophobic patch (WP), or swimmers propelling in the opposite direction (towards the hydrophilic side) (AP). In both systems we have systematically tuned swimmers' hydrophobic strength and signature, and observed that the anisotropic interactions, characterized by the angular attractive potential and its interaction range, in competition with the active stress, pointing towards or against the attractive patch gives rise to a rich aggregation phenomenology.