Activity enhances transport while competing interactions preserve structure in colloidal microphase formers

TL;DR

This study uses Brownian Dynamics simulations to show that activity in colloidal SALR suspensions enhances particle mobility while preserving structure, revealing a decoupling of structure and dynamics.

Contribution

It demonstrates that activity can increase mobility without disrupting structure in SALR colloids, highlighting non-equilibrium structural memory effects.

Findings

Activity increases particle mobility in SALR suspensions.

Structural transitions in active suspensions resemble passive ones with temperature.

Activity induces a decoupling of structure and dynamics.

Abstract

Colloidal models with short-range attraction and long range repulsion (SALR) have been extensively studied using theoretical and simulations methods due to their rich and universal equilibrium phase behavior. Using Brownian Dynamics simulations, we study the dynamical phase behavior of active suspensions in which colloidal particles interact with each other via a SALR potential. Upon increasing the self-propulsion force of the particles, we observed that the structural transitions the active suspension undergoes resemble those observed in its passive counterpart by increasing the temperature of the thermal bath. However, when looking at the transport properties of active and passive suspensions with similar structure, we observed a clear mismatch. We demonstrated that increasing the activity enhances the particles mobility within the SALR fluid when simultaneously preserves the structure. This leads to a structure-dynamics decoupling induced by the activity whereas at the same time highlights the structural memory of SALR potentials under non-equilibrium conditions.