Phase diagram of patchy colloids: towards empty liquids

TL;DR

This paper explores the phase diagram of patchy colloids, demonstrating that reducing bonded neighbors can create stable, low-density liquid states and expand the liquid phase region, potentially leading to equilibrium gels.

Contribution

It introduces a theoretical and numerical analysis showing how fewer bonded neighbors in patchy colloids enable low-density liquids and stable gels, unlike spherical particles.

Findings

Low-density liquid states are achievable with patchy colloids.

Reduction of bonded neighbors increases the stability region of the liquid phase.

Stable equilibrium gels can form at small packing fractions.

Abstract

We report theoretical and numerical evaluations of the phase diagram for patchy colloidal particles of new generation. We show that the reduction of the number of bonded nearest neighbours offers the possibility of generating liquid states (i.e. states with temperature $T$ lower than the liquid-gas critical temperature) with a vanishing occupied packing fraction ($\phi$), a case which can not be realized with spherically interacting particles. Theoretical results suggest that such reduction is accompanied by an increase of the region of stability of the liquid phase in the ($T$-$\phi$) plane, possibly favoring the establishment of homogeneous disordered materials at small $\phi$, i.e. stable equilibrium gels.