Production of NiMn2O4 hollow spheres and CoFe2O4 bowl-like structures by using block copolymer stabilized polystyrene spheres as a hard template.

ABSTRACT

The aim of this study is to highlight the use of polystyrene (PS) latexes stabilized with block copolymers as a hard template in the production of metal oxide hollow spheres. PS latexes produced by dispersion polymerization by stabilizing with tertiary amine methacrylate-based diblock copolymer were used as a hard template in the preparation of nickel manganese oxide (NiMn2O4) hollow spheres and cobalt iron oxide (CoFe2O4) bowl-like structures. Thanks to the diblock copolymer stabilizer with tertiary amine functional groups on the PS surface, precursor salts of CoFe2O4 and NiMn2O4 were first homogeneously deposited on the surface of PS latexes with a controlled precipitation technique. Then, metal oxide hollow spheres and bowl-like structures were produced by calcination. XRD results showed that CoFe2O4 and NiMn2O4 structures were successfully obtained after calcination. The thermogravimetric analysis results showed that the CoFe2O4 and NiMn2O4 contents of the hybrid PS spheres were in the range of 26.0-28.6 wt%. SEM images showed that the inorganic-polymer spheres fused with each other after calcination to form larger magnetic CoFe2O4 bowl-like structures. SEM images also indicated successful production of highly rough NiMn2O4 hollow spheres with nanosheets on the surface.