Simulating inverse patchy colloid models

TL;DR

This paper introduces a versatile patchy model for simulating nano- to micro-sized particles with complex charge interactions, combining attraction and repulsion, and implements it in Monte Carlo and Molecular Dynamics simulations.

Contribution

It presents a new simple, adaptable model for directional charge interactions and provides implementation tools for both Monte Carlo and Molecular Dynamics methods.

Findings

Model effectively captures complex charge interactions.

Implementation in LAMMPS and Monte Carlo offers versatile simulation options.

Comparison of methods provides insights into optimization and performance.

Abstract

Nano- to micro-sized particles with differently charged surface areas exhibit complex interaction patterns, characterized by both opposite-charge attraction and like-charge repulsion. While several successful models have been proposed in the literature to describe directional attraction, models accounting for both directional attraction and directional repulsion are much less numerous and often tailored to specific microscopic systems. Here we present a simple and versatile patchy model, where the interaction energy of a pair of particles is a sum of interactions between sites of different types located within the particle volume. We implement different formulations of this model in both a self-developed Monte Carlo code and the widely used LAMMPS Molecular Dynamics simulation software, providing basic toolkits for both simulation methods and, in the latter case, for different algorithms. By comparing physical observables and code performances, we discuss the different models, methods, and algorithms, offering insights into optimization strategies and tricks of trade.