Interaction of particles and a moving ice-liquid interface

Abstract A cryomicroscope was used to determine critical interface velocities marking the transition between repulsion and entrapment of spherical latex particles by an advancing ice-liquid interface. The employed freezing stage yields a planar ice front which propagates with increasing velocity into a region of decreasing thermal gradients. It was found that the critical velocity associated with the transition is inversely proportional to the particle radius as suggested theoretically under the assumption of the flat front (no cusping behind the particle). The critical velocity increases about linearly with the imposed thermal gradient which seems to stabilize the front against the perturbation induced by the particle. On the other hand, concentration gradients did not show a major effect: the addition of solute (0.56 mol% NaMnO4) did not result in a significant change of the transition points as compared to the results obtained in pure water.