Dendritic Barium Tungstate Nanocrystals Preparation by Microemulsion Method

With the increasing maturity of nano-preparation technology, the development of nano-materials with different morphologies and sizes and the study of the effects of size and morphology on the properties of materials have become one of the main directions of nano-technology research. The traditional inorganic luminescent materials are prepared into nano-materials with certain morphology. The performance of luminescent materials can be further improved by using nano effect.

Barium tungstate with scheelite structure has excellent luminescent properties and good color rendering and discoloration effect. It can be used as photoluminescent or laser donor materials, and has broad application prospects and potential market development value. At present, inorganic nanomaterials of various shapes have been successfully synthesized, such as nanowires, nanotubes, nanoribbons, nanosheets and nanodendrites. Dendritic nanocrystals, because of their special three-dimensional shape, are of great significance to the study of crystal growth mechanism and the development of special properties, and have attracted the attention of materials scientists all over the world.

Studies have shown that dendritic crystals may help to disperse other substances into composites or introduce controllable structures into composites. Microemulsion method can be used to prepare dendritic barium tungstate nanocrystals. The specific processes include:

1)13.42 ml n-octane, 1.08 ml n-butanol and 1.2 g cetyltrimethylammonium bromide (CTAB) were added in a 50 ml conical bottle, and 0.2 mol L^-1 barium chloride aqueous solution of 2 ml was added under magnetic stirring. Stirring for thirty minutes to form a transparent barium ion microemulsion.

2) 13.42 ml n-octane, 1.08 ml n-butanol and 1.2 g cetyltrimethylammonium bromide (CTAB) were added in a 50 ml conical bottle, and 0.2 mol L^-1 sodium tungstate solution of 2 ml was added under magnetic stirring. Stirring for thirty minutes to form homogeneous transparent tungstate ion microemulsion.

3) The two microemulsions containing barium chloride and sodium tungstate were mixed rapidly at 25 ℃ and stirred for 1 minute until the reaction was over. Dendritic barium tungstate nanocrystals can be obtained by centrifugal separation, repeated washing with deionized water and absolute ethanol and vacuum drying at 60 ℃ for 6 hours. The trunk length of the obtained branch structure is 3-6 um and the branch length is 300-500 nm.

Dendritic barium tungstate nanocrystals were prepared by microemulsion method. The reaction temperature was low and the reaction time was short. It took only 1 minutes. The operation procedure was simple, the cost was low, the yield was high, and the repeatability was good. The size distribution of the dendritic nanocrystals was uniform.

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