Direct synthesis of hierarchical monolithic silica for high performance liquid chromatography

The silica-based monolith exhibiting a hierarchical bimodal porous structure has been directly synthesized via lytropic mesophase. The hydrolysis and condensation of tetramethoxysilane (TMOS) in the presence of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (P123) and acetic acid results in silica monolith with MSU-type mesoporous structure embedded in the skeleton of the interconnected macropore. The silica monolith with bimodal porous structure can separate benzene and phenol with high flow rate and low back-pressure. Moreover, the chromatographic property of C₁₈-grafted silica monolith is investigated in the separation of aromatic molecules. Our primary result shows that the silica monolith with interconnected macropore and MSU-type mesopore is a promising packing material as stationary phase for high performance liquid chromatography.