Abstract
The formation of mesostructured silica was investigated using acidic conditions with tetraethoxysilane (TEOS) as the silica precursor and cetyltrimethylammonium bromide (CTAB) as the structure directing agent. A synthesis mixture of composition 2.2TEOS: 1.1CTAB: 75HCl:1000H2O gave a well ordered material exhibiting a range of particle shapes from extended rope-like structures of hexagonal cross-section to gyroid structures. Addition of monomethyltriethoxysilane (MTES) or tetrahydrofuran (THF) to the synthesis mixture gave rise to spherical particles. Studies of particle development showed initial growth of gel-like particles within which the mesostructure developed. A new model is proposed for the formation of mesostructured precipitates in which (1) growth of inorganic oligomers gives rise to a thermodynamically unstable mixture, (2) phase separation occurs giving droplets of a second liquid (or liquid crystal) phase rich in oligomer and surfactant, (3) the droplets are colloidally stabilized, (4) microphase separation occurs within the droplets, giving rise to a mesostructure and (5) further polymerization fixes the mesostructure.
| Original language | English |
|---|---|
| Pages (from-to) | 951-957 |
| Number of pages | 6 |
| Journal | Journal of Materials Chemistry |
| Volume | 11 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2001 |
Keywords
- Order; Particle shape (control of tetraethoxysilane-derived mesostructured silica particle morphol.); Porous materials (mesoporous, silica; control of tetraethoxysilane-derived mesostructured silica particle morphol.); Particles (spherical, silica; control of tetraethoxysilane-derived mesostructured silica particle morphol.)