Study On The Preparation And Modification Of The VO₂ Functional Nanomaterial

In this dissertation, with the use of different starting materials and dopants, doped VO₂ nanopowders were prepared by reductive reaction and precipitation method. The interrelated chemical and physical properties of the products were tested and analyzed by XRD, XPS, TEM, DSC and IR. The investigations showed its phase transition temperature decreased when Mo⁶⁺ was doped into VO₂;however, the grains agglomerated seriously. If W⁶⁺ doped into VO₂ by precipitation method, it reduced the phase transition temperature to 35.7℃, the grains dispersed uniformly, and the analyses of the temperature dependence of IR absorption spectra showed that during the phase transition the products had remarkable changes of the optical transmission. Further more, the efficiency of the two dopants weakened with the increase of their content in the samples.As the agglomeration was a Gordian knot in the preparation of nanomaterials, a new method utilizing oleic acid as modifier was developed to modify the surface of VO₂. All tests indicated that VO₂ was successfully modified with oleic acid and the adsorption of water was lessened, then the dispersion of sample was obviously improved. After modified, the structure of VO₂ didn't change and also had the abrupt change of infrared light transmittance.Based on the works above-mentioned, ethylene vinyl acetate polymer and highly dispersed doped VO₂ were used to prepare the composite film of controllable thickness and even color. Then its optical property was analyzed by the temperature dependence of IR, and the results indicated that there had changes of infrared light transmittance of the composite film. The composite film had the optical properties as same as VO₂ nanopowders...