Novel synthesis and molecularly scaled surface hydrophobicity control of colloidal mesoporous silica

Colloidal mesoporous silica (CMS) has been synthesized using novel surfactant cetyltrimethylammonium tosylate (CTATos) as templates at very low concentration (CTATos/TEOS or TMOS = 0.06 in molar ratio). The combined characterizations of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N₂ adsorption shows that mesoporous silica nanoparticles in size of 50-60 nm are highly monodispersed and exhibit worm-like porosity with large surface area (934 m ²/g) and pore volume (2.57 cm³/g). Surface hydrophobicity control on the molecular level in the confined nanospace of colloidal mesoporous silica is studied using ethyl-1,2-bis (dimethylsilyl) silane (EBDMS) as silylating agent. Infrared (IR) spectroscopy and thermalgravimetric (TG) analysis shows the strong evidences that currently used organosilane (EBDMS) can more effectively tailor the surface hdyrophobicity of mesoporous materials, compared to traditional trimethylchlorosilane. Such a partially silylated colloidal mesoporous silica having hydrophilic sites will be a good support to design new catalyst with isolated active sites.