Preparation and chromatographic properties of ordered macroporous polymer monoliths by colloidal crystal templating method

The ability to control the homogeneous morphology and tune the macropore size is of great significance for tailoring monolithic columns with ideal separation performance. In this paper, the preparation of three-dimensionally ordered macroporous polymer monoliths (OMMC) by a colloidal crystal templating method is reported. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption and thermal analysis were used to characterize the chemical composition, pore structure and thermal stability of the OMMC. The results demonstrated that ordered macroporous carboxyl-functionalized polyester monolithic column (OEMC) and ordered macroporous carboxyl-functionalized polystyrene monolithic column (OSMC) could be successfully prepared by using SiO₂ colloidal crystals as porogen. Both OEMC and OSMC had a three-dimensionally ordered macroporous structure with high porosity, submicron-scale pore walls and macropores. Their macropore diameters were easily controlled from 192 to 772 nm by using different monodisperse SiO₂ beads. Compared to OEMC, OSMC had higher mechanical strength and showed greater solvent resistance to water and methanol. The permeability of OSMCs was 1.33 ~ 3.59 × 10^–15 m². Depending on the electrostatic force, a 4.6 × 10 mm short column had an ability to distinguish between lysozyme (LYZ) and bovine serum albumin (BSA). The highest column efficiencies (n) corresponding to LYZ and BSA were 5494 and 1992 N·m⁻¹, respectively. This study will provide valuable guiding suggestions for the development of 3DOM monolithic columns.