الفهرس 
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Abstract
Fabrication of photochromic inks are gaining much research interest as they have many diverse applications such as photovoltaic, bio-medical, and anti-counterfeiting. New photochromic film was developed for the preparation of anticounterfeiting documents utilizing inorganic/organic nanocomposite enclosing a photoluminescent inorganic pigment and a polyacrylic binder polymer. The produced nanocomposite exhibited a fluorescent color change with an optimum excitation wavelength at 358 nm. To generate a translucent film from pigment/polyacrylic nanocomposite, the phosphorescent strontium aluminum oxide pigment should be well-dispersed in the solution of the polyacrylic-based binder without agglomeration. The photochromic nanocomposite was applied efficiently onto commercial cellulose paper documents utilizing the effective and economical spray-coating technology followed with thermofixation. A homogeneous photochromic film was immobilized onto cellulose paper surface to introduce a transparent film changing to greenish-yellow upon exposure to ultraviolet light as depicted by CIE coloration measurements. The photochromic effect was monitored at lowest pigment concentration (0.25 wt٪). The spray-coated paper documents exhibited two absorption bands at 256 and 358 nm as well as two fluorescence peaks at 433 and 511 nm. Different analytical methods were applied to explore the morphological properties and chemical composition of the spray-coated paper documents, including the scanning electron microscope (SEM), Fouriertransform infrared spectroscopy (FTIR), atomic force microscopy (AFM), wavelength dispersive X-ray fluorescence spectrometry (WDXRF) and energy-dispersive X-ray spectroscopy (EDAX). The chemical structure of the synthesized lanthanide-doped strontium aluminum oxide was studied by X-ray powder (XRD), while the average diameter of the pigment nanoparticles was determined by transmission electron microscope (TEM). The spray-coated paper sheets showed a reversible photochromic effect without fatigue under ultraviolet irradiation. The rheology of the produced photochromic composites as well as the mechanical properties and photostability of the spray-coated documents were studied.