PERMOLECULAR CRYSTALLIZATION IN SUSPENSIONS OF MONODISPERSE SPHERICAL SILICA PARTICLES OF SUBMICROMETER SIZE

Abstract

The regular structures of noble opal form as a result of permolecular crystallization of concentrated suspensions of structural units (SU) represented by charged monodisperse spherical silica particles (MSSP) surrounded by a double diffusion cloud of counter-ions. Under natural conditions, this means water alkaline suspensions with K+ and Na+ counter-ions. Alcoholic MSSP suspensions stabilized by ammonia are commonly used in expernimental practice. The question arises as to whether the nonametric regular structures of heavy MSSPs resulted from the permolecular crystallization or is a result of gravitational packing after the achievement of a specific MSSP weight. The solution of this problem is important for the production of heigh-quality photon crystals that are active in the near-infrared wavelength range. In this communication, we report the first results of the calculation of the balance of the acting forces for nanometric particles and discuss crystallization of suspensions containing such particles.