# Mesoscale simulation of soft particles with tunable contact angle in multi-component fluids

## TL;DR

This paper introduces a lattice Boltzmann-based simulation method for dense suspensions of soft particles in multi-component fluids, capturing complex interfacial behaviors and particle dynamics.

## Contribution

It presents a versatile numerical approach to model soft particles at fluid interfaces, including effects of contact angle and particle softness, validated through various simulations.

## Key findings

- Accurately models particle equilibrium shape at fluid interfaces.
- Shows influence of contact angle and softness on particle displacement.
- Demonstrates complex behaviors like adsorption and coating in simulations.

## Abstract

Soft particles at fluid interfaces play an important role in many aspects of our daily life, such as the food industry, paints and coatings, and medical applications. Analytical methods are not capable of describing the emergent effects of the complex dynamics of suspensions of many soft particles, whereas experiments typically either only capture bulk properties or require invasive methods. Computational methods are therefore a great tool to complement experimental work. However, an efficient and versatile numerical method is needed to model dense suspensions of many soft particles. In this article we propose a method to simulate soft particles in a multi-component fluid, both at and near fluid-fluid interfaces, based on the lattice Boltzmann method, and characterize the error stemming from the fluid-structure coupling for the particle equilibrium shape when adsorbed onto a fluid-fluid interface. Furthermore, we characterize the influence of the preferential contact angle of the particle surface and the particle softness on the vertical displacement of the center of mass relative to the fluid interface. Finally, we demonstrate the capability of our model by simulating a soft capsule adsorbing onto a fluid-fluid interface with a shear flow parallel to the interface, and the covering of a droplet suspended in another fluid by soft particles with different wettability.