Synthesis, characterization, and antibacterial action of hollow ceria nanospheres with/without a conductive polymer coating

Hollow ceria nanospheres were synthesized using anionic polystyrene lattices which were prepared by emulsion polymerization of styrene using potassium persulfate as the initiator. These anionic colloidal particles were dispersed in water in the presence of poly(vinylpyrrolidone) and mixed with aqueous solutions of cerium (III) acetylacetonate [Ce(acac)(3)]. Subsequently, hollow nanospheres of cerium compounds were obtained by calcination of the coated polystyrene lattices at an elevated temperature in air. The hollow ceria nanospheres were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and differential thermal analysis. The hollow ceria nanospheres were coated with conductive polymers (polyaniline and polypyrrole) via an electropolymerization process. Moreover, the antibacterial action of illuminated hollow ceria nanospheres and hollow ceria nanospheres coated with conductive polymers (CPCeO2) on a pure culture of Escherichia coli was studied. A decrease of E. coli concentration was observed after illumination of bacteria in the presence of hollow ceria nanospheres and CPCeO2.