Ordered circular mesoporosity induced by phospholipids

Circular mesoporous materials with different geometries have been prepared by surfactant-templated sol–gel synthesis involving the condensation of tetraethylortosilicate (TEOS) under basic conditions. In this study, cetyltrimethylamonium bromide (CTAB) has been used as a surfactant and controlled amounts of l-α-phosphatidylcholine (lecithin) as a co-surfactant. For small concentrations of lecithin, the obtained materials retain the hexagonal pore ordering characteristic of MCM-41, as evidenced by X-ray diffraction and electron microscopy. However, the channels are no longer straight and parallel but circular and concentric. At higher concentrations of lecithin, vesicular silica was produced.