Influence of Random Pinning on the Crystallization Process in Suspensions of Hard Spheres

Sven Dorosz,Tanja Schilling

doi:10.4236/jcpt.2014.42012

Abstract

We discuss crystal formation in supersaturated suspensions of monodisperse hard spheres with a concentration of hard spheres randomly pinned in space and time. The pinning procedure introduces an external length scale and an external time scale that restrict the accessible number of configureurations and ultimately the number of pathways leading to crystallization. We observe a significant drop in the nucleation rate density at a characteristic pinning concentration that can be directly related to the structure of the critical nucleus and the dynamics of its formation in the unpinned system.

Highlights

Homogeneous as well as heterogeneous crystallization are of importance in materials design and production
The concentration of pinned hard spheres can directly be translated into a length scale that interferes with the typical size of a critical cluster
When the length scale imposed by the pinned hard spheres becomes smaller than the diameter of the critical nucleus, crystal nucleation is suppressed

Summary

Introduction

Homogeneous as well as heterogeneous crystallization are of importance in materials design and production. (2014) Influence of Random Pinning on the Crystallization Process in Suspensions of Hard Spheres. Schilling controlled manner to understand how sensitive the crystallization process and, in particular, the induction time are with respect to changes in configureuration space. The method we employ is to take a configureuration of hard spheres and to pin a randomly chosen fraction of them to their current positions. This approach is called the random pinning model (RP) in the literature. The concentration of pinned hard spheres can directly be translated into a length scale that interferes with the typical size of a critical cluster. The frustration due to the pinned hard spheres on long time scales is resolved

Simulation Method

Dynamic Properties in the Different Pinning Scenarios

Crystallization with Static Pinning

Crystallization with Periodic Pinning

Conclusions