Synthesis of fine monodispersed colloidal spheres and fabrication of high-quality colloidal crystals using the spheres

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The purpose of this study is to fabricate almost perfect close-packed colloidal crystals. To establish the fabrication, we tried the following three experiments : 1) synthesis of highly monodispersed colloidal spheres, 2) in situ observation of self-assembling process and evaluation of crystallinity in the fabricated colloidal crystals, and 3) fundamental investigations for possibilities of recovering defects by laser annealing.As a result, we found that is was difficult to obtain extremely high-quality colloidal crystals even though we used highly monodiperesed polystyrene(PS) spheres with the monodispersity less than 1%, because drying of water shrank the spheres. However, several useful findings were obtained through this study.1. Synthesis of highly-monodispersed colloidal spheres(1) It was necessary for the evaluation of monodispersity less than 1% to read diameters of the synthesized spheres in transmission microscope images.(2) PS spheres with monodispersity less than 1% were synthesized in the diameter range between 250 and 500 nm.(3) Cross-linked PS spheres with the glass transition temperature more than 120 C and the monodipersity less than 3% were synthesized.2. Fabrication of colloidal crystals(1) The changes of the growth manner in the growth rate was found by in situ observation of the growth process of colloidal crystals in a fluidic cell with a conforcal laser microscope.(2) We established a new method for 3D structure analysis of colloidal crystals and revealed the anisotropy of the colloidal crystals composed of PS spheres.(3) The striped structure often observed in the crystals prepared by a convective flow method was revealed to be due to repeated twins.3. Fundamental investigations of laser annealingObservations of melting and recrystalization by laser annealing in the close-packed colloidal crystals containing water between the spheres indicated a possibility that laser annealing will recover defects and introduce intentional defects.