Copolymer-Assisted Synthesis Of Oxide Nanomaterials

The point of this dissertation is to discuss the effect of copolymers in synthesis of inorganic materials. Zinc oxide and ferric oxide particles were prepared. How to control size and morphology was discussed. Now sum up as follows:1,Novel hollow lotus architectures of wurtzite ZnO were prepared through a simple solution method with the assistance of triblock copolymers of PEO₁₀₆PPO₇₀PEO₁₀₆(F127). Thus-prepared ZnO nanostructures were characterized by X-ray diffraction (XRD), field-emission-scanning electron micrographs (FESEM), high-resolution electron microscopy (HRTEM), Fourier transform infrared (FTIR), Brunauer-mmett-Teller (BET) nitrogen adsorption-desorption and Raman spectrum etc. Based on a serial of contrast experiments, an in-situ micelle templating effect of F127 and the intrinsic crystal growth habit of wurtzite ZnO were proposed the key factors determining the formation of the special hollow nanostructures. A broad photoluminescence emission band centered at 393 nm using an excitation wave of 325 nm was observed for the porous ZnO flowers at room temperature. We also discussed the operation of F68 and F127 in the synthesis of ZnO.2,By hydrothermal treatment,α-Fe₂O₃ with spindle and plate-like structures were successfully prepared with the assistance of triblock copolymers of EO₂₀PO₇₀EO₂₀(P123). The influence of many factors, such as the pH value, surfactants and the reactants, has been discussed. When we use ferric nitrate as reactant, the spindles were gained. However, if we changed it into ferric citrate, the plates were gained. The reason was hypothesized to be related to the difference of the crystallization rate and the growth tendency. Meanwhile, magnetic properties of the products were systematically investigated. The as-prepared iron oxides had high coercivity and saturation magnetization, which interested us very much. Through the advanced analysis, we found that iron also existed in the production. We speculate that it is the iron that was deoxidized by citric acid and was protected by Fe3+ in the surface.