Tungsten oxide nanoparticles for transparent thermal insulation material can be prepared by a solvothermal method. For example, some experts studied the effect of solution concentration on the morphology of nano tungsten oxide produced by solvothermal method using ethanol as the alcohol solvent. Wherein, the temperature was 180°C, and the reaction time was 24h. SEM of tungsten oxide nano particles at different solution concentration using ethanol as alcohol solvent is shown as below.
More details, please visit:
http://www.tungsten-powder.com/tungsten-oxide.html
From the figure, we can see that under the conditions of keeping reaction temperature, time, tungsten source and alcohol solvent unchanged, and of changing the molar concentration of tungsten source in alcohol solvent, the obtained products are all nanosphere particles. When the molar concentration of the solution of tungsten chloride in ethanol is 5mM, the form of the reaction product is a large block and the surface of the nanorod particles is densely packed, and is not agglomerated into nanosphere particles. When the molar concentration of the solution is 15mM, the nanorods agglomerate to form nanosphere particles with good uniformity. As the molar concentration of solution increases, the uniformity of nanospheres decreases slightly, and the nanospheres have a joint growth, which is especially noticeable when the molar concentration of the solution is 25mM. The formation of the bulk region composed of nanospheres increases the degree of crystallization, which is presumably due to the increase in the tungsten source and the influence of the WO3 phase.
