Porous structure of hypercrosslinked polystyrene: State-of-the-art mini-review

The paper evaluates accumulated information about the apparent inner surface area (Sapp), pore volume (Wo), pore size (diameter, D), and pore size distribution (PSD) of the single-phase hypercrosslinked polystyrene networks prepared by an intensive post-crosslinking of either dissolved linear polystyrene or swollen gel-type styrene-divinylbenzene copolymers. Critical analysis of data obtained by conventional physical methods used for the characterization of porous solids (low temperature adsorption of nitrogen or argon, mercury intrusion porosimetry, inversed size exclusion chromatography, electronic microscopy, positronium annihilation) reveals the most trustworthy porosity parameters of the above hypercrosslinked polystyrene resins as Sapp ⩾ 1000 m2/g, Wo in the range of 0.3-0.5 cm3/g, D in dry networks from 4-5 to 30 Å and only slightly increasing in swollen samples. The hypercrosslinked networks thus present first basically microporous polymeric material that exhibits narrow PSD resulting from a statistically uniform distribution of crosslinks.