Synthesis of silica mesoporous crystals with controlled structure and morphology using gemini surfactant

Silica mesoporous crystals with different morphologies were prepared based on the self-assembly of the gemini cationic surfactant [C16H33N+(CH3)(2)(CH2)(3)N+(CH3)(3)]Br-2(C16-3-1) and tetraethyl orthosilicate (TEOS) in water under acidic condition. By controlling the kind of acids (H2SO4 or HQ, temperature and synthesis compositions, three well-ordered silica mesoporous crystals, cubic Fm(3)m, three-dimensional hexagonal P6(3)/mmc and cubic Pm3n, with distinct morphologies were synthesized. In the synthesis system with H2SO4. the crystals changed the structure from Pm3n to Fm3m with decrease in acidity and increase in synthesis temperature; and in the synthesis with HCl. the crystals with Fm3m and P6(3)/mmc were synthesized by changing the synthesis compositions, especially C16-3-1/H2O and C16-3-1/TEOS molar ratios. (C) 2007 Elsevier Inc. All rights reserved.