| 研究実績の概要 |
We applied a direct synthesis using tetraethyl orthosilicate (TEOS) and reactive organosilanes and a grafting of the organosilanes on monodisperse silica (d = 20 nm). The organosilanes we used were n-(6-aminohexyl)aminopropyltrimethoxysilane (AHP-TMS), 3-isocyanatopropyltriethoxysilane (CP-TES) and (3-glycidyloxypropyl)trimethoxysilane (GP-TMS). Since the organic group, AHP, of the first silane can react with those of the last two, CP and GP, AHP-modified silica nanoparticles, AHP-silica, were mixed with CP-modified or GP-modified silica nanoparticles, CP-silica and GP-silica, respectively, and gently grinded by a pestle on the mortar.
In the pore size distributions of AHP-silica and CP-silica prepared by direct synthesis as well as those after the reaction of these two functionalized silica particles, a broad peak is found at 23 nm for AHP-silica, while at 13 nm for CP-silica. However, after the mixing reaction, the distribution becomes narrow and the peak appears at 8 nm. If AHP-silica and CP-silica are physically mixed, the pore does not become narrower than the smaller one (13 nm). The peak shift implies selective distribution of CP-silica around AHP-silica and shortening the organic chains. In the pore size distributions of GP-silica and the solid after the mixing reaction with AHP-silica. GP-silica provides no peak in the meso region. However, a prominent peak emerges at 13 nm after the mixing reaction. This is, again, the porous structure that does not appear by physical mixing.
|
