A Study On The Preparation Of Micro/Nano Particles Via Mixed Solvent Method

Morphology and size of material have significant influence on the material properties and applications. To develop effective methods for achieving the controlling of material morphology and size, a novel method, mixed solvent method has been studied in the present thesis.Mixed solvents were prepared by mixing water and organic solvents including ethanol, acetone, DMF, THF at different ratios. Micro/nano particles of inorganic materials including MnCO3, NiCO3and A1NH4(SO4)2-12H2O, polymers including ABS and PS were prepared via mixed solvent method. The influence of mixed solvents on the particle size and morphology was investigated with analysis method including XRD, TEM, SEM and TG-DTA. The results were shown below:1. With increasing content of organic solvent in the mixed solvent, the surface tension of the mixed solvent decreased first rapidly and then slowly. Similarly, the solubility of inorganic materials including MnCO3, MCO3and AlNH4(SO4)2·12H2O in the mixed solvent also decreased first rapidly and then slowly when the content of organic solvent in the mixed solvent increased.2. Particle size of inorganic materials including MnCO3, NiCO3and A1NH4(SO4)2·12H2O can be controlled with mixed solvent method. Generally speaking, with the increasing content of organic solvent in the mixed solvent, particle size of inorganic materials decreased from a few micrometers to below100nanometers, and the morphology of these particles changed accordingly.3. Particle size and morphology of polymers including ABS and PS can be controlled by changing the ratio of water to organic solvent in the mixed solvent. Surfactant also play important role in these systems. In the mixed solvent system of water and THF, when the ratio of water to THF was4:1, well dispersed PS spherical particles were prepared with narrow size distribution and average diameter of about100nm. Innovations of this thesis:inorganic materials and polymers with different particle size and morphology were prepared through dissolution-precipitation process, depending on the difference of solubility of inorganic materials and polymers in different solvents.