Nonequilibrium design strategies for functional colloidal assemblies

TL;DR

This paper develops a nonequilibrium variational approach to optimize shear-induced transformations in colloidal assemblies, revealing how shear flow can enhance reactivity and flux in nanoclusters beyond equilibrium constraints.

Contribution

It introduces a variational principle combined with stochastic optimization to discover novel nonequilibrium design strategies for functional colloidal materials.

Findings

Shear flow can significantly increase transition rates between colloidal states.

Shear flow can break detailed balance and maximize probability currents.

Flux between nanoclusters can be amplified without harming microphase structure.

Abstract

We use a nonequilibrium variational principle to optimize the steady-state, shear-induced interconversion of self-assembled nanoclusters of DNA-coated colloids. Employing this principle within a stochastic optimization algorithm allows us to discover design strategies for functional materials. We find that far-from-equilibrium shear flow can significantly enhance the flux between specific colloidal states by decoupling trade-offs between stability and reactivity required by systems in equilibrium. For isolated nanoclusters, we find nonequilibrium strategies for amplifying transition rates by coupling a given reaction coordinate to the background shear flow. We also find that shear flow can be made to selectively break detailed balance and maximize probability currents by coupling orientational degrees of freedom to conformational transitions. For a microphase consisting of many nanoclusters, we study the flux of colloids hopping between clusters. We find that a shear flow can amplify the flux without a proportional compromise on the microphase structure. This approach provides a general means of uncovering design principles for nanoscale, autonomous, functional materials driven far from equilibrium.