Kinetic control of the coverage of oil droplets by DNA-functionalised colloids

TL;DR

This study demonstrates how to control the surface coverage of oil droplets by DNA-functionalized colloids through reversible adsorption, enabling the preparation of colloid-coated droplets with fixed loading but dynamic colloids, and explores their phase behavior.

Contribution

It introduces a method to control colloid coverage on oil droplets and investigates the resulting phase behavior and dynamics, supported by simulations.

Findings

Controlled colloid coverage achieved before structural arrest.

Colloids exhibit ergodic dynamics on droplets.

Simulations illustrate compositional arrest and phase behavior.

Abstract

We report a study of reversible adsorption of DNA-coated colloids on complementary functionalized oil droplets. We show that it is possible to control the surface coverage of oil droplets by colloidal particles, by exploiting the fact that during slow adsorption, compositional arrest takes place well before structural arrest occurs. As a consequence, we can prepare colloid-coated oil droplets with a `frozen' degree of loading, but with fully ergodic colloidal dynamics on the droplets. We illustrate the equilibrium nature of the adsorbed colloidal phase by exploring the quasi two-dimensional (2d) phase behaviour of the adsorbed colloids under the influence of depletion interactions. We present simulations of a simple model that illustrates the nature of the compositional arrest and the structural ergodicity.