PREPARATION AND CHEMICAL FIXATION OF POLY(4-VINYLPYRIDINE) MICROGEL FILM WITH ORDERED STRUCTURE

Poly(4-vinylpyridine) (P4VP) microgel films with ordered structure were prepared by casting the deionized aqueous solutions of monodispersed microgel followed by a drying process at 60-degrees-C; the microgels then were fixed chemically by a number of methods using dihalobutane or p-(chloromethyl)styrene as the cross-linking agent. Besides the scanning electron microscopic (SEM) observation and the spectrophotometric measurement, a special method, by which the bond angles composed of three particles can be calculated from two SEM micrographs of the same place at different angles around one rotating axis, was devised to determine the arrangement of the microgels in films. A film showing beautiful iridescence where the pores between microgels were conserved was obtained for the solid microgel, while semitransparent films in which the pores between microgels vanished were obtained for the soft microgels. The arrangement of particles in these films almost showed face-centered cubic (a few parts in films maybe showed simple hexagonal packing). The films after chemical fixation became insoluble in methanol and water and other good solvents for quaternized or nonquaternized P4VP. The films in which the pores between microgels were conserved or vanished were obtained dependent on the different methods of fixation. The scanning electron microscopic observation confirmed that the ordered arrangement was not destroyed even after fixation by the chemical treatment of microgels.