Ordering hard-sphere particle suspensions by medium crystallization: Effect of size and interaction strength.

Abstract

While microstructure in soft materials is usually given by the self-assembly of their constituting building blocks, colloidal assembly can also be obtained via templating a morphology in a disordered suspension of particles by solidification of the melt. This order-templating process is applicable to different soft-matter systems with a variety of characteristic length scales, including particle suspensions in water, liquid-crystal materials, and polymer melts. In this work, we numerically investigate the effect of particle size and solvent size in the process of solidification templating by implementing a coarse-grain model of hard-sphere particles at a moving melt-crystal interface. This approach captures the dependence of crystallization templating on speed of crystal growth, showing the existence of a threshold speed for crystallization templating to occur. Results in this work show that the threshold speed changes following a power form as solvent size and particle size change. Furthermore, this work analyzes and reports the effect of particle-crystal interaction strength in combination with size effects. This scaling study from a numerical perspective sets a starting point for the development of hybrid soft materials via structural templating, allowing solidification-driven particle ordering in different systems with a variety of length scales.