Immobilization of lanthanide doped aluminate phosphor onto recycled polyester toward the development of long-persistent photoluminescence smart window

Smart window can be defined as switchable material whose light transmission is altered upon exposure to light, voltage, or heat. However, smart windows are usually produced from expensive and breakable glass materials. Herein, transparent smart window with long-persistent phosphorescence, high optical transmittance, ultraviolet (UV) protection, rigid, high photostability and durability, an d superhydrophobicity was developed from recycled polyester (PET). Recycled polyester waste (RBW) was simply immobilized with different ratios of lanthanide-doped aluminate nanoparticles (LdAN) to provide a long-persistent phosphorescent polyester smart window (LdAN@PET) with an abili ty to persist emitting light for extended time periods. The solid-state high temperature technique was used to prepare lanthanide-doped aluminate (LdA) micro-scale powder. Then, the top-down technique was applied to afford the corresponding LdAN. Recycled shredded recycled polyester bottles were charged into a hot bath to provide a clear plastic shred bulk, which was then well-mixed with LdAN and drop-casted to provide long-persistent luminescent smart window. In order to improve the phosphor dispersion in the PET bulk, LdAN was synthesized in the nanoparticle form which was characterized utilizing transmission electron microscopy (TEM). For better preparation of translucent smart window of long-persistent phosphorescent polyester, LdAN must be homogeneously dispersed in the PET matrix without agglomeration. The morphology and chemical composition were studied by Fourier-transform infrared (FTIR) spectra), X-ray fluorescence (XRF) analysis, scanning electron microscopy (SEM), and energy-dispersion X-ray spectroscopy (EDX). In addition, spectral profiles of excitation and emission, and decay and lifetime were used to better understand the photoluminescence properties. The hardness properties were also investigated. The developed phosphorescent transparent polyester smart window demonstrated a color switch to intense green underneath UV irradiation and greenish-yellow under darkness as verified by CIELab color parameters. The afterglow polyester smart window showed an absorption wavelength at 365 nm and two phosphorescence intensities at 442 and 512 nm. An enhanced UV protection, photostability and hydrophobic activity were detected. The luminescent polyester substrates with lower LdAN ratios demonstrated rapid and reversible fluorescent photochromic activity beneath the UV light. The luminescent polyester substrates with higher LdAN contents displayed long-persistent phosphorescence afterglow. The current strategy can be simply applied for the production of smart windows, low thickness anti-counterfeiting films and warning signs.     

Preparation of photoluminescent nano-biocomposite nacre from graphene oxide and polylactic acid

Nano-biocomposites of inorganic and organic components wereprepared to produce long-persistent phosphorescent artificial nacre-like materials. Biodegradable polylactic acid (PLA), graphene oxide (GO), and nanoparticles (13–20 nm) of lanthanide-doped aluminate pigment (NLAP) were used in a simple production procedure of an organic/inorganic hybrid nano-biocomposite. Both polylactic acid and GO nanosheets were chemically modified to form covalent and hydrogen bonding. The high toughness, good tensile strength, and great endurance of those bonds were achieved by their interactions at the interfaces. Long-persistent and reversible photoluminescence was shown by the prepared nacre substrates. Upon excitation at 365 nm, the nacre substrates generated an emission peak at 517 nm. When ultraviolet light was shone on luminescent nacres, they displayed a bright green colour. The high superhydrophobicity of the generated nacres was obtained without altering their mechanical characteristics.     

Immobilization of biomolecular anthocyanin natural sensor into plasma-cured polyethylene terephthalate fibers from recycled plastic waste for determination of ammonia

Polyester textiles have been applied in numerous industrial applications. Polyester fibers are characterized with being excellent insulators to electricity, having excellent flexural and impact strength, ease of manufacture, low-cost, as well as having resistance to moisture and chemicals. However, polyester fibers cannot be stained due to the absence of active dyeing sites on the surface of the fibrous structure. Thus, polyester cannot be dyed after it has been extruded. Herein, we report the development of novel-colored polyester fabrics using plasma-assisted dyeing and anthocyanin natural probe for determination of ammonia that may cause severe harmful effects to human organs and even death. Anthocyanin was extracted from red cabbage and characterized. The water-soluble anthocyanin was fastened to polyester fibers by mordant (potash alum) to generate anthocyanin–mordant coordinative complex nanoparticles. Polyester can be treated with thin layer of anthocyanin probe after activation with plasma. The results showed excellent colorfastness, ultraviolet blocking, and antibacterial performance of the anthocyanin-dyed polyester (APET) fibers. The APET fibers showed great potential for developing a portable colorimetric device for an on-site detection of ammonia. APET displayed a detection limit of aqueous ammonia in the range of 25–200 ppb, displaying a change in color from purple (542 nm) to white (387 nm).