Synthesis of functional photopolymerized macroporous polyHIPEs by atom transfer radical polymerization surface grafting

A versatile platform to obtain highly functional macroporous materials was developed. A polymerizable initiator for atom transfer radical polymerization (ATRP) has been incorporated into a high internal phase emulsion (HIPE) without compromising the emulsion stability. Photopolymerization of this formulation led to polyHIPE with ATRP initiator groups on the surface available for polymer grafting reactions. The latter was first demonstrated by grafting of methylmethacrylate (MMA). Analysis by IR confirms the presence of PMMA in the polyHIPE. Moreover, scanning electron microscopy images show changes in the surface morphology of the polyHIPE after the grafting reaction. In accordance with the controlled character of ATRP, reinitiation from the PMMA-grafted polyHIPE with HEMA to afford block copolymers was possible. Moreover, functionalized polyHIPE was obtained by the grafting of glycidyl methacrylate. IR and SEM analysis confirm that this resulted in a smooth and homogeneous coverage of the polyHIPE surface with a high density of reactive epoxy groups. In a subsequent reaction these materials were rendered hydrophilic by ring opening of the epoxy rings and hydrophobic by subsequent reaction with pentafluorobenzoylchloride.