Preparation And Photochromic Properties Of Flexible Ammonium Metatungstate/PVP Composite Fiber Membrane

The abuse of paper can cause excessive tree felling and affect sustainable development strategies.The ink-free rewritable paper has attracted wide attention as a new printing medium.The rewritable paper manufacturing material not only requires a sensitive color conversion response to external stimuli(such as light,heat,electricity,etc.),but also has a cyclic "write-erase" function.Among them,the photoresponsive rewritable paper has broad application prospects due to its fast non-contact writing method and pollution-free characteristics.Based on the photochromic properties of ammonium metatungstate,an ammonium metatungstate/PVP(polyvinylpyrrolidone)photochromic composite fiber membrane was prepared as a new rewritable paper.The effect of process parameters on its photochromic properties was studied.The photochromic mechanism was analyzed,which provided a new idea for the preparation of low-cost,high-performance rewritable paper.Aiming at the cumbersome preparation of traditional photochromic materials,this paper prepared a flexible ammonium metatungstate/PVP photochromic fiber membrane by using air-spinning technology with ammonium metatungstate as raw material.And the higher the content of ammonium metatungstate in the fiber membrane,the better the photochromic performance.When the ammonium metatungstate content is 200 wt.%,the photochromic properties of the fiber membrane are optimized.The 30 W xenon lamp reaches absorbance saturation for 25 s,and the fiber film still maintains good photochromic performance and clear resolution after 100 “write-erase” cycles.The fiber membrane prepared by the method has the advantages of low cost,simple process,reusability and environmental friendliness,and has great application prospect in the field of rewritable medium for temporary information storage.In order to break through the limitation of poor waterproof performance of traditional photochromic materials,based on the characteristics of PDMS(polydimethylsiloxane)waterproofing,the above fiber membranes were encapsulated by PDMS to prepare waterproof ammonium metatungstate/PVP@PDMS.Photochromic composite fiber membrane.The package of PDMS increases the light response rate of the fiber membrane,and the absorption saturation state can be achieved in 10 s under the same illumination conditions,and the pattern resolution is higher.Moreover,the fiber membrane after PDMS encapsulation treatment has good waterproof and mechanical properties,which has great advantages compared with the commonly used A4 paper.