Synthesis and Characterization of Mesoporous Silica Vesicles Using Cationic-anionic Binary Surfactant as Template

Mesoporous silica vesicles were synthesized using cationic surfactant hexadecyl trimethyl ammonium bromide(CTAB) and anionic surfactants sodium dodecyl sulfonate(SDS) in molar ratios of 1.0-2.3 as templates, tetraethyl orthosilicate(TEOS) as silica source at 68°C in ammonia solution medium. The samples were characterized by scanning electron microscopy(SEM), small angle X-ray diffraction(SXRD), transmission electron microscopy(TEM), thermo gravimetric analysis(TGA) and nitrogen adsorption-desorption isotherms measurments. The results indicate that the samples are the continue aggregates of mesoporous silica vesicles with diameters of ca. 50 nm. The Brunauer-Emmett-Teller(BET) surface area and nonlocal density functional theory(NLDFT) pore diameter of the samples are 826 m2/g and 4.0 nm, respectively. The formation mechanism of the vesicles was also discussed.