Development of silica‐coated rare‐earth doped strontium aluminate toward superhydrophobic, anti‐corrosive and long‐persistent photoluminescent epoxy coating

Abstract

Long‐persistent phosphorescent smart paints have the ability to continue glowing in the dark for a prolonged time period to function as energy‐saving products. Herein, new epoxy/silica nanocomposite paints were prepared with different concentrations of lanthanide‐doped aluminate nanoparticles (LAN; SrAl2O4:Eu2+,Dy3+). The LAN pigment was firstly coated with silicon dioxide (SiO2) utilizing the heterogeneous precipitation technique to provide LAN‐encapsulated between SiO2 nanoparticles (LAN@SiO2). The epoxy/silica/lanthanide‐doped aluminate nanoparticles (ESLAN) nanocomposite paints were coated on steel. The prepared ESLAN paints were studied by transmission electron microscopy (TEM), Fourier‐transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X‐ray fluorescence (XRF) analysis, and energy‐dispersive X‐ray spectroscopy (EDS). The transparency and coloration properties of the nanocomposite coated films were explored by CIE Lab parameters and photoluminescence spectra. The ultraviolet‐induced luminescence properties of the transparent coated films demonstrated greenish phosphorescence at 518 nm upon excitation at 368 nm. Both hardness and hydrophobic activities were investigated. The anticorrosion activity of the nanocomposite films coated onto mild steel substrates immersed in aqueous sodium chloride (NaCl(aq)) (3.5%) was studied by electrochemical impedance spectroscopy (EIS). The silica‐containing coatings were monitored to exhibit anticorrosion properties. Additionally, the nanocomposite films with LAN@SiO2 (25%) exhibited the optimized long‐lasting luminescence properties in the dark for 90 min. The nanocomposite films showed highly reversible and durable long‐lived phosphorescence.

Dual mode stimuli‐responsive color‐tunable transparent photoluminescent anticounterfeiting polycarbonate electrospun nanofibers embedded with lanthanide‐doped aluminate

“…The RESAO@PC films exhibited transparent backgrounds, which aided in the detection of the ultravioletinduced color change to green emission. [29][30][31][32] After being exposed to ultraviolet light, all RESAO@PC nanofibers exhibited an instantaneous and reversible photochromism. Nonetheless, the RESAO@PC samples with RESAO ratio below 0.9% showed fluorescence with quick reversibility after switching off the UV source.…”

“…On the other hand, a phosphorescent substance continues to emit light after turning the excitation light source off. This phosphorescent light emission continues for seconds (phosphorescence) or even hours (afterglow) 30–32 . Numerous photoluminescence uses, such as warning signs, make extensive use of rare‐earth doped phosphors.…”

“…This phosphorescent light emission continues for seconds (phosphorescence) or even hours (afterglow). [30][31][32] Numerous photoluminescence uses, such as warning signs, make extensive use of rare-earth doped phosphors. Numerous rare-earth doped phosphors with varying primary colorimetric emissions have been described in the literature, such as CaAl 2 O 4 :Eu 2+ , Nd 3+ as bluish emitters, 33 CaS:Eu 2+ , Tm 3+ , Ce 3+ as red emitters, 34 and SrAl 2 O 4 :Eu 2+ , Dy 3+ as greenish emitters.…”

Photoluminescent and photochromic smart window from recycled polyester reinforced with cellulose nanocrystals

“…Thermal quenching, conversely, might reduce the blue intensity to practically nothing. [40][41][42][43][44][45] As a result, only a highly concentrated greenish colour can be monitored. The luminescence spectra did not show any emission caused by Eu 3+ ions, indicating that the Eu 2+ ions were responsible for the observed emission.…”

“…The light traps created by dysprosium were released in the dark, reverting Eu 2+ back to its initial ground state. [40][41][42][43][44][45] It was shown that UV irradiation did not degrade the polyester sample with 11% pigment content (Figure 12), which was treated to many cycles of decolorizing and colouring before and after UV exposure.…”