Orientationally Glassy Crystals of Janus Spheres

TL;DR

This study investigates the glasslike orientational dynamics of Janus spheres in water, revealing how anisotropic interactions and ionic strength influence their rotational behavior, providing insights into nontrivial glassy phenomena.

Contribution

It introduces Janus spheres as a model system to study orientational glassy dynamics driven by directional interactions, combining experiments and simulations.

Findings

Orientational correlations exhibit glasslike dynamics.

Ionic strength controls the dynamics.

Janus spheres serve as a model for nontrivial glass behavior.

Abstract

Colloidal Janus spheres in water (one hemisphere attractive and the other repulsive) assemble into two-dimensional hexagonal crystals with orientational order controlled by anisotropic interactions. We exploit the decoupled translational and rotational order to quantify the orientational dynamics. Via imaging experiments and Monte Carlo simulations we demonstrate that the correlations in the orientation of individual Janus spheres exhibit glasslike dynamics that can be controlled via the ionic strength. Thus, these colloidal building blocks provide a particularly suitable model glass system for elucidating nontrivial dynamics arising from directional interactions, not captured by the consideration of just translational order.