Oil swollen surfactant gel based synthesis of metal oxides nanoparticles: An attractive alternative for the conventional sol gel synthesis

Metals (Zr, Zn and Cu) containing oil swollen surfactant gels have been utilized as precursors for the preparation of metal oxides (ZrO2, ZnO and CuO) nanoparticles. No metal alkoxide, external gelating agent or any other intricate molecule have been utilized to reinforce gelation; gel stage has been achieved simply through judicial adjustment of water to surfactant ratio and salinity of the reaction mixture. Unlike, several previously published reports, in this approach surfactant has been added not to just increase the viscosity of solution but it has also formed rod shaped gelatinous micelles in response to the variation in water to surfactant ratio, which endowed mechanical strength to the gel. The effect of nature of metal salt on mechanical properties of gel has also been investigated. Zn and Cu containing cetyltrimethylammonium bromide (CTAB) gels have been found to be strongest and weakest, respectively. Metal containing CTAB gels were heat treated at various temperatures (600, 700 and 800 °C) in order to obtain metal oxides nanoparticles. The effect of calcination temperature on crystallinity, particle size and morphology of the metal oxides nanoparticles has also been investigated. A comparison between ZrO2 nanoparticles prepared using conventional sol gel and oil swollen surfactant gel method has also been carried out in terms of crystallinity, particle size and optical property.