Synthesis of Ultrahigh Surface Area Monodisperse Porous Polymer Nanospheres

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 μm in diameter and are essentially nonporous in the dry state having only a very nominal surface area (∼10 m 2 g -1 ). Cross-linking of appropriate dichloroethane swollen precursors with a high content of VBC residues in the presence of FeCl 3 (i.e., using a Davankov-type strategy) yields near monodisperse porous hyper-cross-linked nanoparticles with extremely high surface areas up to ∼1200 m 2 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 m 2 g -1 .