Mixtures of anisotropic and spherical colloids: Phase behavior, confinement, percolation phenomena and kinetics

TL;DR

This paper reviews recent research on the phase behavior, percolation, and kinetics of suspensions of anisotropic and spherical hard particles, highlighting effects of particle shape and interactions in both equilibrium and non-equilibrium contexts.

Contribution

It provides a comprehensive overview of how particle anisotropy influences phase transitions, percolation, and crystallization in hard particle suspensions.

Findings

Anisotropy affects percolation thresholds and phase behavior.

Depletion interactions modify connectivity and phase transitions.

Kinetics of crystallization differ between spheres and ellipsoids.

Abstract

Purely entropic systems such as suspensions of hard rods, platelets and spheres show rich phase behavior. Rods and platelets have successfully been used as models to predict the equilibrium properties of liquid crystals for several decades. Over the past years hard particle models have also been studied in the context of non-equilibrium statistical mechanics, in particular regarding the glass transition, jamming, sedimentation and crystallization. Recently suspensions of hard anisotropic particles also moved into the focus of materials scientists who work on conducting soft matter composites. An insulating polymer resin that is mixed with conductive filler particles becomes conductive when the filler percolates. In this context the mathematical topic of connectivity percolation finds an application in modern nano-technology. In this article, we briefly review recent work on the phase behavior, confinement effects, percolation transition and phase transition kinetics in hard particle models. In the first part, we discuss the effects that particle anisotropy and depletion have on the percolation transition. In the second part, we present results on the kinetics of the liquid-to-crystal transition in suspensions of spheres and of ellipsoids.