Novel hypercrosslinking approach toward high surface area functional 2-hydroxyethyl methacrylate-based polyHIPEs

Abstract

Highly porous poly(2-hydroxyethyl methacrylate-co-N,N′-methylenebisacrylamide) (poly(HEMA-co-MBAA)) frameworks were prepared from oil-in-water high internal phase emulsions (HIPEs). After subsequent functionalization through a two-step synthetic pathway involving i) activation of the hydroxyl functions exposed at the pore surface and ii) functionalization with allylamine or propargylamine, two different functionalized porous polymers were obtained and characterized in terms of porosity and chemical composition through mercury intrusion porosimetry, nitrogen adsorption-desorption porosimetry, and Raman spectroscopy, respectively. A final step relying on radical thiol-ene/yne “click” additions with di- or tetrathiols was further investigated so as to hypercrosslink the resulting porous materials and eventually decorate the pore surface with thiol functions. Very high specific surface area values as determined by nitrogen sorption porosimetry were found, namely up to 1500 m2.g−1 for HEMA-based material functionalized with allylamine after hypercrosslinking with pentaerythritol. In-situ generated gold nanoparticles were immobilized at the pore surface, and one such strategy allowed for the preparation of hybrid materials that were successfully applied for the supported heterogeneous catalytic reduction of a nitroaromatic compound, i.e.p-nitrophenol, and of a pollutant dye used in textile industry, i.e. Eosin Y.