Production of photochromic nanocomposite film via spray‐coating of rare‐earth strontium aluminate for anti‐counterfeit applications
2021; Wiley; Volume: 36; Issue: 8 Linguagem: Inglês
10.1002/bio.4127
ISSN1522-7243
AutoresOmnia M. Mokhtar, Yasser A. Attia, Ahmed R. Wassel, Tawfik A. Khattab,
Tópico(s)Gold and Silver Nanoparticles Synthesis and Applications
ResumoNew photochromic film was developed toward the preparation of anti-counterfeiting documents utilizing inorganic/organic nanocomposite enclosing a photoluminescent inorganic pigment and a polyacrylic binder polymer. 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 exhibit two absorbance bands at 256 and 358 nm, and two fluorescence peaks at 433 and 511 nm. The morphologies of the spray-coated documents were explored. 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.
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