Nanofibrous, hypercrosslinked polymers with multiscale pores through post-crosslinking of emulsion-templated syndiotactic polystyrene aerogels

Although emulsion-templated aerogels could be advantageous over polyHIPEs, their hypercrosslinking has not been explored yet. Herein, we report hypercrosslinking emulsion-templated syndiotactic polystyrene (sPS) aerogels through Friedel-Crafts alkylation to generate hypercrosslinked, hierarchically porous sPSs. The macroporous structures and nanofibrous structures, imposed by emulsion-templating, were well preserved for the hypercrosslinked sPSs. The hypercrosslinked sPSs showed extremely low density and hierarchical pores in three different scales: emulsion-templated macropores, macro/mesopores among nanofibers and micropores generated from hypercrosslinking. The hypercrosslinked sPSs exhibited enhanced specific surface areas and super-hydrophobicity, enabling to be used for removing oils on water surface, underwater oils and emulsified oils. The hypercrosslinked sPSs showed enhanced thermal stability, enabling them to be carbonized to produce carbon foams with hierarchical pores, demonstrating the hypercrosslinked sPSs to be suitable as precursors of hierarchically porous carbon foams.