| The tungsten oxide is a multifunctional inorganic oxide material,which is also one of the most photochromic properties.In recent decades,due to nanometer properties of tungsten oxide nanomaterials,the performance of the material itself has been greatly improved,which has attracted the attention of many researchers.However,there continue to be some problems in the tungsten oxide,such as unstable crystal phase structure,long photochromic response time and short life.And other issues.In this paper,tungsten oxide nano-powder was prepared by a simple hydrothermal method.The morphology,crystal structure and optical properties of the synthesized nano-powder were studied.Selecting tungsten oxide nano powder material with the best performance,and preparing composite films,yarns and fabrics with photochromism by using a coating method;Polyacrylamide/tungsten oxide composite hydrogels were prepared by aqueous solution polymerization and analyzed by optical performance test.The main research work is as follows:Sodium tungstate dihydrate is selected as a tungsten source for preparing tungsten oxide nano-powder,oxalic acid serving as an auxiliary agent and potassium sulfate serving as an inducer are added to obtain the nano-tungsten nano-sheet,and the size range of the nano-tungsten nano-sheet is 300-600nm.The tungsten oxide nano-sheet with the best performance is selected.Under the radiation of an ultraviolet lamp,the color of the powder changes within 5 seconds,and the color gradually deepens after 5 seconds.Therefore,the prepared tungsten oxide nano-powder has the effect of changing the color within a few seconds.In the process of preparing photochromic composite film/cotton yarn/cotton fabric,WOx/PVP composite coating solution was prepared by using PVP and tungsten oxide mixed uniformly to coat the WOx/PVP coating solution.A photochromic composite film/yarn/fabric was prepared onto a PET/cotton yarn/cotton fabric.The composite prepared film/yam/fabric has a color change under the induction of ultraviolet light.The prepared photochromic composite film has good photochromic reversibility,and its absorption spectrum coloration increased from～0.267 to～0.576 under ultraviolet light,and then recovered to～0.269,and the recovery ability was close to 100%,indicating photochromism.The reversibility of the material;Moreover,the fading state was best under heating at a temperature of 80 C,and the composite photochromic film prepared had excellent reversibility after 10 cycles of coloring-fading and had no significant cycle fatigue.The photochromic prepared yarn has photochromic ability,and the strength of the coated yarn is significantly higher than that of the pure cotton yarn,and can be used to weave various interesting fabrics.The photochromic hydrogel prepared by aqueous solution polymerization has a color change effect in a few seconds under an ultraviolet lamp with a power of 72 W and a wavelength of 254 nm.In summary,the photochromic tungsten oxide nanopowder prepared by the hydrothermal method has the advantages of low cost,environmental friendliness,and mass production,and is present in the field of flexible rewritable media.Great application potential;the color-changing powder material nano-particle prepared by hydrothermal method combined with PET/yarn/fabric to prepare photochromic composite inorganic color-changing composite film/yarn/fabric,expanding tungsten oxide in composite film/yarn/fabric applications.At the same time,a reliable method for preparing photochromic hydrogels based on the combination of inorganic photochromic materials and non-toxic polymer materials polyacrylamide was explored.The photochromic hydrogel lithography was successfully studied by using hydrogel as the substrate.Applications in areas such as erasing optics. |
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