Periodic mesoporous hybrid monolith with hierarchical macro-mesopores

We describe the synthesis of hybrid monolith with hierarchically macro-mesoporous structure by a sol-gel process from the mixture of 1,4-bis(triethoxysilyl)benzene (BTEB) and tetraethoxysilane (TEOS) using poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (P123) as structure directing agent under acid medium. The ordered mesoporous structure is embedded in the skeleton of the well-defined co-continuous macropore of the hybrid monolith. The influence of aging condition, acidic concentration, P123/Si ratio and TMB/P123 ratio on the macro- and meso-structure of the resultant monolith was investigated in details. The three-successive aging processes are necessary for the mesostructural order of the monolith to survive the surfactant removing process. The well-defined co-continuous macropore could be formed with the aid of TMB, which probably delays the phase separation rate during the sol-gel process through enhancing the interaction between the hydrophobic BTEB with P123 surfactant micelles. The macro-mesoporous hybrid monolith with phenylene bridged in the mesoporous framework may have potential application as a novel kind of stationary phase for high performance liquid chromatography (HPLC).