Preparation of amino-functionalized mesoporous silica thin films with highly ordered large pore structures

Highly ordered amino-functionalized mesoporous silica thin films have been directly synthesized by co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) in the presence of triblock copolymer Pluronic P123 surfactant species under acidic conditions by sol-gel dip-coating. The effect of the sol aging on thin films organization is systematically studied, and the optimal sol aging time is obtained. The amino-functionalized mesoporous silica thin films exhibit a long-range ordering of 2D hexagonal (p6mm) mesostructure with a large pore size of 8.3 nm, a large Brunauer–Emmett–Teller (BET) specific surface area of 680 m² g⁻¹ and a large pore volume of 1.06 cm³ g⁻¹ following surfactant extraction as demonstrated by X-ray diffraction (XRD), Transmission electron microscope (TEM), and physical adsorption techniques. Based on BET surface area and weight loss, the surface coverage of amino-groups for the amino-functionalized mesoporous silica thin films is calculated to be 3.2 amino-groups per nm². Moreover, the functionalized thin films display improved properties for immobilization of cytochrome c in comparison with pure-silica mesoporous thin films.