| 초록 |
The distribution of macropores in silica particles prepared by the hydrolysis and condensation of TEOS in hexane/water/decylalcohol (O1/W/O2) multiple emulsion was investigated. To stabilize the emulsion structure, hydroxypropyl cellulose (HPC) was added into O2 phase and polyethylene glycol (PEG) was added into the water phase. Without HPC, the particles have the irregular shape and hardly have the particular form. As the concentration of HPC increased, the shape of particles become more and more spherical form and the size was decreased. The size of silica particles was varied from 0.005 to 0.001 mm as the concentration of HPC increased from 0.5 to 0.7 wt%. The number and size of the macropores in silica particles were affected by PEG polymer concentration. With the variation in the concentration of PEG, macropores in silica particles were located at the surface or inside of the particles. At high concentration of PEG, the macropores in particles were located inside of the particles, but at low concentration of PEG the macropores were located at the surface of particles. Interestingly, the particles of dimpled surfaces were formed when the molar ratio of water to TEOS (Rw) was 4.0 and the concentrations of PEG and HPC were 2.0 and 0.7 wt.% respectively. The surface areas measured by BET method of dimpled silica particles and completely spherical particles were 409 and 433 m2/g respectively. |
