Synthesis of ultra-high surface area monodisperse polymer nanoparticles

Synthesis of vinyl benzyl chloride (VBC)/divinylbenzene (DVB) copolymers via surfactant-free emulsion polymerization yields near monodisperse chloromethylated polystyrene precursor nanospheres 400 nm in diameter. These are analogous to gel-type suspension polymerized particles typically of 100-500 ím in diameter and are essentially nonporous in the dry state having only a very nominal surface area (10 m2 g-1). Cross-linking of appropriate dichloroethane swollen precursors with a high content of VBC residues in the presence
of FeCl3 (i.e., using a Davankov-type strategy) yields near monodisperse porous hyper-cross-linked nanoparticles with extremely high surface areas up to 1200 m2 g-1. The latter display all the characteristics of Davakov-type resins in terms of their ability to sorb both thermodynamically “poor” and “good” solvents and in particular despite their superficial hydrophobic makeup are able to sorb significant quantities of water (up to 2.5 g/g). By adjusting the content of VBC in the precursor particles, the surface area of the near monodisperse nanoparticles
can be adjusted in the range 15-1300 m2 g-1.