Videomicroscopic Observation of Nonequilibrium Growth Patterns of Crystals

We have developed a video‐microscopic computer imaging system for observing meso‐scale nonequilibrium physicochemical structures. Chargcd‐coupled device (CCD) in optical detection, and computer‐enhancement of digitized image, have greatly improved the resolution, sensitivity, and dynamical range of this technique. We apply this system to the observation of various complex crystallization patterns from Suberic acid melts and Camphene condensation. These patterns are of the scale one to 100 micrometers. They are resulted from nonlinear dynamical instabilities of a growing crystal fronts. The following patterns are observed: dendrites, destabilization of flat surface, cellular solidification, tip‐splitting, and dense branches. A computer simulation based on diffusion‐limited aggregates (DLA) model is performed to show this instability. The DLA model with surface tension effect is able to result in fractal‐like, dendrite, and needle‐like growth pattern.