Tuning morphology and surface properties of emulsion-templated porous polymers by controlled radical polymerization

Macroporous polymer monoliths with interconnected structures have attracted considerable interests in the last decades and sustain many applications in the fields of supported catalysis, chromatography, microfluidic, water purification, membrane separation, tissue engineering, to name but a few. A very popular and straightforward synthetic approach for such open-cell polymers is the High Internal Phase Emulsion (HIPE) polymerization method. The latter consists in three steps: (i) stabilization of an emulsion in which an internal phase with a volume fraction higher than 74% is dispersed within a minor continuous phase containing a polymer network precursor, (ii) curing of the polymer phase by polymerization or crosslinking reactions, (iii) removal of the internal phase to release the porosity. The surface properties and morphology of the polyHIPEs are important features that must be controlled and adjusted for each applications. In this context, we prepared by controlled radical polymerization a series of well-defined amphiphilic copolymers having different hydrophilic-lipophilic balance (HLB) and chain-ends, used it as stabilizers for the emulsion-templated polymerizations and demonstrated the crucial effect of the structure of the macromolecular surfactant on the morphology of the polyHIPEs. Finally, the physical and chemical anchoring of the macromolecular surfactants at the surface pores were also considered for tuning the surface properties of the porous monoliths.