(234e) Control Polymorphism, Size and Surface Properties of Particulate Materials

The size, crystalline phase (polymorphism), morphology and surface chemistry of particles greatly affect the chemical activity and physical properties of particulate materials, such as solubility, bio-availability, solid handling, dispersivity and separation. Particle properties become a more important issue in industrial applications when the size of particles shrinks down to nano range, which we believe is a future trend of the applications of particulate materials. In this paper, several novel approaches will be presented to control particle size, polymorphism, and surface chemistry. In one example, template-direct nucleation has been successfully used to control the polymorphism by control the interactions between the functional group of template and surface of the nuclei. Another example is using reverse-micelle to control particle size. By using microemulsion method, we have successfully prepared uniform 50 nm-size nanocrystals of a DuPont-confidential material. Surface chemistry of particles will dominate the dispersivity and compatibility of particulate material with different solvent. By synthesizing particles in non-aqueous and modifying the particles in situ with proper surfactant, we have successfully prepared nanoparticles that can be easily re-dispersed into non-aqueous solvent.