火山作用と関係ある無定形ケイ酸の性質とその応用的研究-34-オパ-ル状物質の合成-2-

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Amorphous monodispersed silica spheres with particle size smaller than 0.8 μm were synthesized from the system Si(OC_2H_5)_4-NH_3 (or amine derivative)-H_2O-C_2H_5OH (or n-C_3H_7OH) in the temperature range 1.5-20°C. Silica particles grew larger at lower reaction temperatures. A linear correlation was observed between concentration of ammonia in the range of 0.5-4.0mol/l and average particle size of the silica. Plots of particle size against the concentration of water showed a maximum at about 8mol/l. Under a constant concentration of amine derivative, the growth rate of silica particles increased in the following order; (C_2H_5)_3N<(CH_3)_3N<(C_2H_5)_2NH<(CH_3)_2NH<CH_3NH_2. The diameter of silica spheres decreased to 3/4 of its initial diameter by heating to 1000°C through a two step dehydratio process. A rainbow-colored precipitate, in which silica spheres were close-packed in an ordered array, was obtained by allowing the solution containing monodispersed silica spheres to stand at room temperature for 3 months.
鹿児島大学,カゴシマダイガク,Kagoshima Universityの論文