New crystallization of nano-crystals by high pressure

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The advantages of high pressure crystallization are to distinguish the nucleation process from complicated crystallization processes, and to change the solubility of solute at atmosphere pressure. The pressure can expand into the system at speed of sound, and that is quite different from concentration and temperature which speeds are limited by diffusivity and thermal conductivity. We could have the new apparatus to investigate the solution at more than 4000 bar. The solution can be easily changed in the free-piston type vial. We first observed the nucleation of two ammonium salts at high pressure, and found that the solubility of two ammonium salts could be decreased as pressure increased. Those two salts could be crystallized by high pressure. Moreover, two ammonium salts in aqueous ethanol solution were nucleated at supersaturated solution by high pressure, and the metastable zones for two ammonium salts were found in high pressure crystallization. The width of metastable zone was large when the solubility of salt was small in the solution. The viscosity of ethanol solution that influences the growth of crystal nuclei was also measured at high pressure by DLS method. The viscosity of aqueous ethanol solution became very large as pressure increased, and that could limit the growth of crystal nuclei. In addition, electric conductivity of aqueous ethanol solution was also measured at high pressure. We could developed new high pressure cell having dipoles. The electric conductivities of two ammonium salts in aqueous ethanol solution decreased considerably at high pressure. As a results of this project, we could have new method to charge electron in battery at high speed at high pressure by nucleation process for further project.