Anomalous diffusion and diffusion anomaly in confined Janus dumbbells

TL;DR

This study uses molecular dynamics simulations to explore the self-assembly and anomalous diffusion behaviors of confined Janus dumbbells, revealing diffusion anomalies and superdiffusive regimes in a molecular system without Brownian effects.

Contribution

It demonstrates that diffusion anomalies and self-assembly persist in Janus nanoparticles even without Brownian motion, highlighting the role of two-length scale interactions.

Findings

Diffusion anomaly is preserved without Brownian effects.

Superdiffusive regimes are observed during collective reorientation.

Anomalous diffusion is explained via the two-length scale framework.

Abstract

Self-assembly and dynamical properties of Janus nanoparticles have been studied by molecular dynamic simulations. The nanoparticles are modeled as dimers and they are confined between two flat parallel plates to simulate a thin film. One monomer from the dumbbells interacts by a standard Lennard Jones potential and the other by a two-length scales shoulder potential, typically used for anomalous fluids. Here, we study the effects of remove the Brownian effects, typical from colloidal systems immersed in aqueous solution, and consider a molecular system, without the drag force and the random collisions from the Brownian motion. Self-assembly and diffusion anomaly are preserved in relation to the Brownian system. Additionally, a superdiffusive regime associated to a collective reorientation in a highly structured phase is observed. Diffusion anomaly and anomalous diffusion are explained in the two length scale framework.