Analysis of FT-IR spectra of the sulfonated polystyrene colloidal crystals

Monodispersed polystyrene latexes (100 similar to 500 nm) were prepared using seed emulsion polymerization. Hard and ordered polystyrene colloidal crystals were obtained by ambient drying the monodispersed polystyrene dispersions. Polystyrene colloidal crystals were chemically modified by controlled sulfonation with sulfuric acid to derive a novel macro-ordered hydrogels including ordered hydrogels and core/shell hydrogels, in which sulfuric acid and sulfone groups are responsible for the hydrophilic and crosslinking performances, respectively. The chemical structure and morphologies of the hydrogels were characterized by Fr-IR It is shown that at a given concentration of sulfuric acid, the structural features of the samples are controlled by sulfonation time and temperature. The modification starts from the outer layer of polystyrene spheres of the colloidal crystals and increases both in reaction rate and sulfone group amount with temperature. A preliminary mechanism of the sulfonation process to prepare the ordered structures was proposed.