Preparation of P(MBA-co-MAA)/Zr(OH)_(4)/P(EGDMA-co-MAA)/TiO_(2)Tetra-layer Hybrid Microspheres and the Corresponding ZrO_(2)/TiO_(2)Double-shelled Hollow Microspheres

Double-shelled zirconia/titania(ZrO_(2)/TiO_(2))hollow microspheres were prepared by the selective removal of the polymer components via the calcination of the corresponding tetra-layer poly(N,N'-methylenebisacryl amide-comethacrylic acid)(P(MBA-co-MAA))/Zr(OH)_(4)/poly(ethyleneglycol dimethacrylate-co-methacrylic acid)(P(EGDMAco-MAA))/TiO_(2)hybrid microspheres.These tetra-layer microspheres were synthesized by the combination of the distillation copolymerization of N,N′-methylenebisacryl amide-co-methacrylic acid(MBA)or ethyleneglycol dimethacrylate(EGDMA)crosslinker and methacrylic acid(MAA)for the preparation of polymer core and thirdlayer as well as the controlled sol-gel hydrolysis of inorganic precursors for the construction of zirconium hydroxide(Zr(OH)_(4))and titania(TiO_(2))layers.The thicknesses of zirconia and titania shell-layers were conveniently controlled via varying the feed of zirconium n-butoxide(Zr(OBu)_(4))and titanium tetrabutoxide(TBOT)during the sol-gel hydrolysis,while the sizes of polymer layers were tuned through a multi-stage distillation precipitation copolymerization.The structure and morphology of the resultant microspheres were characterized by transmission electron microscopy(TEM),X-ray diffractometer(XRD),X-ray photoelectronic spectroscopy(XPS),and thermogrametric analysis(TGA).