A Light Scattering Study of Solvent Solidification in Colloidal Suspensions

Intermolecular forces between a solid and a foreign substrate can lead to the formation of a thin film of liquid between the two surfaces at temperatures below the solid's bulk melting temperature. These forces also result in fluid flow towards colder regions of the interface when a temperature gradient is present. When the fluid component of a colloidal suspension solidifies, the particles become encased within the ice both individually and in clusters. Near the melting temperature, a premelted layer bathes the particles, providing a restricted, but finite volume of liquid that facilitates Brownian motion through the background solid. We will present the results of our X-ray Photon Correlation Spectroscopy experiments by which we can characterize the dynamics of the particles in a solidifying colloidal suspension and thereby extract information about the amount of premelted liquid.