Fabrication of mesoporous silica hollow spheres using triblock copolymer PEG–PPG–PEG as template

We report a single-step, emulsion-templating method using triblock copolymer poly(ethylene glycol)–poly(propylene glycol)–poly(ethylene glycol) (PEG–PPG–PEG) as template, sodium silicate or tetraethylorthosilicate (TEOS) as precursor and n-octane and benzyl alcohol as cosolvents. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results revealed that ordered mesoporous silica hollow microspheres with thickness of shell about 50 nm and mean diameter 1 μm were prepared by changing the concentration of the reactant, pH and reaction time. Brunauer–Emmett–Teller (BET) analysis confirmed that silica hollow microspheres were porous. Generally, the hierarchical structures of mesoporous silica can be regulated from hollow spheres to solid particles by changing the concentration of benzyl alcohol. This methodology provides a versatile and effective route for preparation of mesoporous hollow materials.