Computational and experimental study on the influence of the porogen on the selectivity of 4-nitrophenol molecularly imprinted polymers.

In molecular imprinting the porogen plays a decisive role, as it not only affects the physical properties of the resulting polymer including its porosity, the specific surface area, and the swelling behavior, but also governs the stability of the prepolymerization complex, which in turn decisively determines the recognition properties of the resulting molecularly imprinted polymer (MIP). In this study, the influence of the porogen on the selectivity of MIPs was investigated. Therefore, bulk MIPs against 4-nitrophenol using 4-vinylpyridine (4-VP) as functional monomer and ethylene glycol dimethacrylate (EDMA) as crosslinker were prepared in acetonitrile and chloroform. The recognition properties of both MIPs were evaluated during chromatographic studies using the respective porogenic solvents as mobile phase for both MIPs. Along with the characterization of the morphology of the obtained polymers via SEM and BET analysis, the beneficial nature of chloroform as porogen for imprinting 4-NP was experimentally demonstrated and verified by findings obtained from complementary molecular dynamics simulations. Moreover, the application of chloroform as mobile phase for the MIP prepared in acetonitrile and vice versa clearly demonstrated the dependence of the resulting recognition properties on the selection of the mobile phase.