Asymmetric Assembly of Lennard-Jones Janus Dimers

TL;DR

This study investigates the detailed orientations and assembly behaviors of Janus dimers in fluid environments using molecular dynamics and energy calculations, revealing preferred angles and solvent effects on their configuration.

Contribution

It provides high-resolution analysis of Janus dimer orientations, highlighting the influence of solvent and hydrophobicity on their assembly, which was not previously characterized in detail.

Findings

Most probable center-center-pole angles are 40° to 55°.

Pole-to-pole alignment is not observed due to entropy.

Relative azimuthal angle is influenced by solvent ordering.

Abstract

Self-assembly of Janus (or `patchy') particles is dependent on the precise interaction between neighbouring particles. Here, the orientations of two amphiphilic Janus spheres within a dimer in an explicit fluid are studied with high geometric resolution. Molecular dynamics simulations and first-principles energy calculations are used with hard- and soft-sphere Lennard-Jones potentials, and temperature and hydrophobicity are varied. The most probable centre-centre-pole angles are in the range 40{\deg} to 55{\deg}, with pole-to-pole alignment not observed due to orientational entropy. Angles near 90{\deg} are energetically unfavoured due to solvent exclusion, and we unexpectedly found that the relative azimuthal angle between the spheres is affected by solvent ordering.