METHODS TO DETERMINE CRYSTAL LATTICE PARAMETERS OF OPAL-LIKE STRUCTURES
Series of high-quality spherical poly(methyl methacrylate) particles with a polydispersity less than 5% are prepared by chain-growth emulsifier-free controlled radical emulsion polymerization of methyl methacrylate in water. The average diameters in the series varied from 237 nm to 447 nm. The physico-chemical properties of obtained submicrospheres can be varied to make them more stable and stronger by a modified classical synthesis technology whereby 4-10 vol.% of dispersion medium is replaced by acetone. 2D and 3D photonic crystal structures, opals, are prepared from poly(methyl methacrylate) submicrospheres. The crystal structure of the opals is studied by IR spectroscopy and scanning electron microscopy. According to the spectroscopic data, the poly(methyl methacrylate) particles contain significant amounts of water whose evaporation leads to the shrinkage of the spheres. The stereoregularity of the synthesized polymer is studied, the glass-transition temperatures of obtained samples are determined.