Do cavities matter? Hollow microgels resist crystallization

TL;DR

This study investigates how hollow microgels, distinguished by their central cavity, resist crystallization and form stable supercooled liquids, providing insights into their unique phase behavior in crowded environments.

Contribution

It reveals that hollow microgels exhibit suppressed crystallization and enhanced supercooling due to their cavity structure, supported by experimental scattering data and Monte Carlo simulations.

Findings

Hollow microgels resist crystallization in crowded environments.

Cavities promote supercooled liquid stability.

Experimental and simulation results agree on phase behavior.

Abstract

Solutions of microgels have been widely used as model systems to gain insight into atomic condensed matter and complex fluids. We explore the thermodynamic phase behavior of hollow microgels, which are distinguished from conventional colloids by possessing a central cavity. Small-angle neutron and X-ray scattering are used to probe hollow microgels in crowded environments. These measurements reveal an interplay between interpenetration and deswelling, and an unusual absence of crystals. Monte Carlo simulations of hollow microgel solutions confirm that, due to the cavity, they form a supercooled liquid more stable than in the case of microgels with a crosslinked core.