Crystallization kinetics of repulsive colloidal spheres

Abstract

Colloidal spheres interacting via a purely repulsive potential provide an excellent model system to study the kinetics of solidification from the melt. Such systems are readily accessible by comparably simple yet powerful optical methods like time resolved static light scattering and microscopy, reviewed in the first part of this paper. We then present results from our own recent studies within a framework of data available from literature. In particular we investigated nucleation and growth of hard sphere crystals using combined Bragg and small angle light scattering and of charged sphere crystals using Bragg microscopy. Special attention is given to the range of validity of classical nucleation theory and of Wilson Frenkel growth and a discussion of kinetic prefactors for both processes.

Bcc crystal-fluid interfacial free energy in Yukawa systems

“…One of the implications is that the barrier of crystal nucleation is strongly reduced such that it would be easier to nucleate a bcc-crystal from the melt than a fcc-crystal. 55 Our results can in principle be verified by adjusting experimental data on crystal nucleation in charged suspensions [59][60][61] to classical nucleation theory, where the interfacial free energy enters as one of the crucial parameters.…”

Crystal-liquid interfacial free energy via thermodynamic integration

“…Besides, the assumptions inherent in classical nucleation theory affect the estimates of γ cl . With state-of-the-art experiments, however, γ cl can be estimated in certain parameter ranges with an accuracy of 10-20% [8][9][10].…”

Non-equilibrium melting of colloidal crystals in confinement

“…For observation the cell was mounted on the stage of an inverted microscope (IRB, Leica, Wetzlar, Germany) and monitored with a high resolution CCD camera. Two observation modes were regularly applied: polarization and Bragg microscopy [12]. Data were stored in a computer and image processed to quantify sample structure, morphology and motion.…”

“…Here much less is known about the mechanisms involved to start and dominate the phase transition kinetics in an anisotropic environment. By contrast to the rich literature on the quantitative kinetics of crystal growth [5,11,12], even a qualitative parameterization of the melting kinetics is missing completely. Still open issues are e.g.…”

“…Recently, interest shifted to non equilibrium processes with special focus on phase transitions kinetics and the influence of external fields [5,11,12,13]. By contrast to atomic systems, equilibrium melting is induced through a variation in interaction strength (e.g.…”