RESUMEN
Ammonia is a colorless gas, yet it can be fatal if inhaled or ingested in high enough concentrations. Herein, a solid-state colorimetric smart wool (WL) sensor for ammonia was developed. Common hop (Humulus lupulus L.) is a natural resource of spectroscopical dyestuff known as xanthohumol (XN). Wool fabrics were dyed with different concentrations of xanthohumol extract using the high-temperature high-pressure method in the presence of a mordant. The coloration parameters and absorption spectra were employed to explore the yellow-to-white colorimetric shift of the wool fabric after it was exposed to aqueous ammonia. The wool fabric showed an excellent detection limit of 5 to 125 ppm. When the ammonia concentration was increased, the absorbance spectra demonstrated a hypsochromic shift from 498 nm to 367 nm. This could be attributed to changes in the molecular structure of xanthohumol that happen owing to intramolecular charge delocalization. Using transmission electron microscopy (TEM), the mordant/xanthohumol nanoparticles were measured to have diameters of 15-40 nm. The xanthohumol-finished wool fabrics showed good colorfastness properties. The incorporation of mordant/xanthohumol nanoparticles into wool fabrics showed no negative effects on their stiffness or air-permeability.
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Amoníaco , Flavonoides , Humulus , Propiofenonas , Propiofenonas/química , Humulus/química , Flavonoides/química , Flavonoides/análisis , Amoníaco/química , Amoníaco/análisis , Animales , Extractos Vegetales/química , Fibra de Lana/análisis , Colorimetría/métodos , Nanopartículas/químicaRESUMEN
Counterfeiting of banknotes, important documents, and branded goods continues to be a major worldwide problem for governments, businesses, and consumers. This problem has serious financial, security, and health implications. Due to their stability for printing on various substrates, the photochromic anticounterfeiting inks have received important interest. There have been various photochromic agents, such as polymer nanoparticles, quantum and carbon dots, and organic and inorganic fluorophores and luminophores, which have been broadly used for antiforging applications. In comparison to organic agents, inorganic photochromic materials have better stability under reversible/long-term light illumination. Recently, the remarkable optical characteristics and chemical stability of photoluminescent and photochromic agents have led to their extensive usage anticounterfeiting products. There have been also several strategies to tackle the rising problem of counterfeiting. Both of solvent-based and water-based inks have been developed for security encoding purposes. Additionally, the printing methods, including screen printing, labeling, stamping, inkjet printing, and handwriting, that have been used to apply anticounterfeiting inks onto various surfaces are discussed. The limitations of photoluminescent and photochromic agents and the potential for their future preparation to combat counterfeiting were discussed. This review would benefit academic researchers and industrial developers who are interested in the area of security printing.
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Tinta , Impresión , Procesos Fotoquímicos , Polímeros/química , LuminiscenciaRESUMEN
Cartilage repair remains a major challenge in clinical trials. These current cartilage repair materials can not effectively promote chondrocyte generation, limiting their practical application in cartilage repair. In this work, we develop an implantable scaffold of RADA-16 peptide hydrogel incorporated with TGF-ß1 to provide a microenvironment for stem cell-directed differentiation and chondrocyte adhesion growth. The longest release of growth factor TGF-ß1 release can reach up to 600â¯h under physiological conditions. TGF-ß1/RADA-16 hydrogel was demonstrated to be a lamellar porous structure. Based on the cell culture with hBMSCs, TGF-ß1/RADA-16 hydrogel showed excellent ability to promote cell proliferation, directed differentiation into chondrocytes, and functional protein secretion. Within 14 days, 80% of hBMSCs were observed to be directed to differentiate into vigorous chondrocytes in the co-culture of TGF-ß1/RADA-16 hydrogels with hBMSCs. Specifically, these newly generated chondrocytes can secrete and accumulate large amounts of collagen II within 28 days, which can effectively promote the formation of cartilage tissue. Finally, the exploration of RADA-16 hydrogel-based scaffolds incorporated with TGF-ß1 bioactive species would further greatly promote the practical clinical trials of cartilage remediation, which might have excellent potential to promote cartilage regeneration in areas of cartilage damage.
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Cartílago , Diferenciación Celular , Condrocitos , Hidrogeles , Regeneración , Andamios del Tejido , Factor de Crecimiento Transformador beta1 , Factor de Crecimiento Transformador beta1/metabolismo , Factor de Crecimiento Transformador beta1/farmacología , Regeneración/efectos de los fármacos , Andamios del Tejido/química , Hidrogeles/química , Hidrogeles/farmacología , Humanos , Condrocitos/efectos de los fármacos , Condrocitos/citología , Condrocitos/metabolismo , Diferenciación Celular/efectos de los fármacos , Cartílago/efectos de los fármacos , Cartílago/fisiología , Cartílago/metabolismo , Proliferación Celular/efectos de los fármacos , Ingeniería de Tejidos/métodos , Células Cultivadas , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/citología , Animales , Condrogénesis/efectos de los fármacos , PéptidosRESUMEN
A novel smart biochromic textile sensor was developed by immobilizing anthocyanin extract into electrospun cellulose acetate nanofibers to detect bacteria for numerous potential uses, such as healthcare monitoring. Red-cabbage was employed to extract anthocyanin, which was then applied to cellulose acetate nanofibers treated with potassium aluminum sulfate as a mordant. Thus, nanoparticles (NPs) of mordant/anthocyanin (65-115 nm) were generated in situ on the surface of cellulose acetate nanofibrous film. The pH of a growing bacterial culture medium is known to change when bacteria multiply. The absorbance spectra revealed a bluish shift from 595 nm (purple) to 448 nm (green) during the growth of Gram-negative bacteria (E. coli) owing to the discharge of total volatile basic amines as secretion metabolites. On the other hand, the absorption spectra of a growing bacterial culture containing Gram-positive bacteria (L. acidophilus) showed a blue shift from 595 nm (purplish) to 478 nm (pink) as a result of releasing lactic acid as a secretion metabolite. Both absorbance spectra and CIE Lab parameters were used to determine the color shifts. Various analytical techniques were utilized to study the morphology of the anthocyanin-encapsulated electrospun cellulose nanofibers. The cytotoxic effects of the colored cellulose acetate nanofibers were tested.
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Nanofibras , Antocianinas/farmacología , Escherichia coli , Colorimetría , Celulosa , Lactobacillus acidophilusRESUMEN
Nowadays, the combined knowledge and experience in biomedical research and material sciences results in the innovation of smart materials that could efficiently overcome the problems of microbial contaminations. Herein, a new drug delivery platform prepared by grafting sodium alginate with ß-carboxyethyl acrylate and acrylamide was described and characterized. 9-Aminoacridine (9-AA), and kanamycin sulfate (KS) were separately loaded into the hydrogel in situ during graft polymerization. The grafting efficiency for the resulting hydrogels was 70.01-78.08 %. The chemical structure of the hydrogels, thermogravimetric analysis, and morphological features were investigated. The swelling study revealed that the hydrogel without drugs achieved a superior swelling rate compared to drug-loaded hydrogels. The hydrogel tuned the drug-release rate in a pH-dependent manner. Furthermore, the antibacterial study suggested that the hydrogels encapsulating 9-AA (88.6 %) or KS (89.3 %) exhibited comparable antibacterial activity against Gram-positive and Gram-negative bacterial strains. Finally, the cytocompatibility study conducted on normal lung cell line (Vero cells) demonstrated neglectable to tolerable toxicity for the drug-loaded hydrogel. More interestingly, the cell viability for the blank hydrogel was 92.5 %, implying its suitability for biomedical applications.
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Alginatos , Hidrogeles , Animales , Chlorocebus aethiops , Hidrogeles/farmacología , Hidrogeles/química , Células Vero , Antibacterianos/farmacología , Antibacterianos/química , Sistemas de Liberación de Medicamentos , KanamicinaRESUMEN
A polyester resin was strengthened with electrospun glass nanofibers to create long-lasting photochromic and photoluminescent products, such as smart windows and concrete, as well as anti-counterfeiting patterns. A transparent glass@polyester (GLS@PET) sheet was created by physically immobilizing lanthanide-doped aluminate (LA) nanoparticles (NPs). The spectral analysis using the CIE Lab and luminescence revealed that the transparent GLS@PET samples turned green under ultraviolet light and greenish-yellow in the dark. The detected photochromism can be quickly reversed in the photoluminescent GLS@PET hybrids at low concentrations of LANPs. Conversely, the GLS@PET substrates with the highest phosphor concentrations exhibited sustained luminosity with slow reversibility. Transmission electron microscopic analysis (TEM) and scanning electron microscopy (SEM) were utilized to examine the morphological features of lanthanide-doped aluminate nanoparticles (LANPs) and glass nanofibers to display diameters of 7-15 nm and 90-140 nm, respectively. SEM, energy-dispersive X-ray spectroscopy (EDXA), and X-ray fluorescence (XRF) were used to analyze the luminous GLS@PET substrates for their morphology and elemental composition. The glass nanofibers were reinforced into the polyester resin as a roughening agent to improve its mechanical properties. Scratch resistance was found to be significantly increased in the created photoluminescent GLS@PET substrates when compared with the LANPs-free substrate. When excited at 368 nm, the observed photoluminescence spectra showed an emission peak at 518 nm. The results demonstrated improved hydrophobicity and UV blocking properties in the luminescent colorless GLS@PET hybrids.
RESUMEN
Wastewater, which is rich with heavy elements, dyes, and pesticides, represents one of the most important environmental pollutants. Thus, it has been significant to fabricate environmentally friendly polymers with high adsorption ability for those pollutants. Herein, crosslinked chitosan (C-Cs) was prepared using isopropyl acrylamide and methylene bisacrylamide. Carbon nanoparticles (C-NPs) were also obtained by the treatment of the agricultural wastes, which was used with C-Cs to prepare C-Cs/C-NPs nanocomposite (C-Cs/C-NC). Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscope (TEM) were used to investigate the prepared adsorbent. C-Cs, C-NPs, and C-Cs/C-NC were used in water treatment for the adsorption of lead ions (Pb+2) and methylene blue (MB). The adsorption process occurred by the prepared samples was investigated under different conditions, including contact time, as well as different doses and concentrations of adsorbents. The findings exhibited that the adsorption of Pb+2 and MB by C-Cs/C-NC was higher than C-Cs and C-NPs. In addition, the kinetic and isotherm models were studied, where the results showed that the adsorption of Pb+2 and MB by various adsorbents obeys pseudo-second-order and Langmuir isotherms, respectively.
RESUMEN
Smart windows with long-persistent phosphorescence, ultraviolet (UV) light protection, high transparency, and high rigidity were developed by easily immobilizing varying ratios of lanthanide-activated aluminate phosphor nanoscale particles within a composite of recycled polyester/cellulose nanocrystals (RPET/CNC). Cellulose nanocrystals were prepared from rice straw waste. Cellulose nanocrystals were used at low concentration as both crosslinker and drier to improve both transparency and hardness. The phosphor nanoscale particles must be distributed into the recycled polyester/cellulose nanocrystals composite bulk without agglomeration to produce transparent RPET/CNC substrates. Photoluminescence characteristics were also studied using spectroscopic profiles of excitation/emission and decay/lifetime. The hardness efficiency was also examined. This transparent recycled polyester waste/cellulose nanocrystals nanocomposite smart window has been shown to change colour under UV light to strong green and to greenish-yellow when it is dark, as proved by Commission Internationale de l'éclairage (CIE) laboratory colour parameters. It was found that the afterglow RPET/CNC smart window had phosphorescence intensities of 428, 493, and 523 nm upon excitation at 368 nm. There was evidence of improved UV shielding, photostability, and hydrophobic activity. In the presence of a low phosphor ratio, the luminescent RPET/CNC substrates showed quick and reversible fluorescence photochromic activity when exposed to UV radiation.
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Nanocompuestos , Nanopartículas , Celulosa/química , Luminiscencia , Nanocompuestos/química , Nanopartículas/química , PoliésteresRESUMEN
Linen fibres were coated with a glow-in-the-dark photoluminescence, flame-retarding, and hydrophobic smart nanocomposite using the pad-dry-curing process. Ecologically friendly ammonium polyphosphate and lanthanide-activated strontium aluminium oxide (LSAO) nanoparticles were immobilized into linen fabric using eco-friendly room-temperature-vulcanizing silicone rubber. Different analytical techniques were used to examine the morphological characteristics and elemental compositions of LSAO nanoparticles and treated linen textiles. The self-extinguishing properties of the treated linen textiles were tested for their fire resistance. After 24 washing cycles, the coated linen samples retained their flame-retarding properties. The treated linen's superhydrophobicity rose in direct proportion to the LSAO concentration. After being excited at 365 nm, the colourless luminescent film that was coated on linen surface gave out an emission wavelength of 519 nm. The photoluminescent linen was monitored to create a range of different colours, including off-white in daytime light and green under ultraviolet (UV) light radiation, according to the Commission Internationale de l'éclairage laboratory colorimetric coordinates and photoluminescence spectra. Emission, excitation, and lifetime spectral analysis of the treated linen revealed persistent phosphorescence. For mechanical and comfort evaluation, the coated linen textiles' bending length and air permeability were assessed. Good UV light shielding and enhanced antibacterial activity were detected in the treated linens.
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Nanopartículas , Textiles , Óxido de Aluminio , Antibacterianos/química , Ropa de Cama y Ropa Blanca , Luminiscencia , Nanopartículas/química , EstroncioRESUMEN
A raindrop solar cell can work either on rainy days to collect mechanical energy of the raindrops or on sunny days to harvest solar energy, which achieves high energy conversion efficiency in various energy environments. However, the low efficiency of raindrop energy harvesting is a dominating barrier to the raindrop solar cells in practical applications. In this work, a MoO3/top electrode-based triboelectric nanogenerator (MT-TENG) with high rain droplet energy conversion efficiency, integrated with a perovskite solar cell through shared electrodes, has been proposed. The interface electrons between the triboelectric layer and electrode can be blocked by the MoO3 layer with high permittivity and wide bandgap, and the MoO3-based TENG (M-TENG) therefore increases the surface charge density. Thus, the top electrode structure in the solid-liquid interface can greatly increase the output charge by 101.1 times in total. By adjusting the water droplet parameters of tap water to simulate the actual application scenario, the raindrop output power and mechanical energy conversion efficiency can reach 0.68 mW and 12.49%, respectively. In addition, due to the high transmittance of the MT-TENG, the perovskite solar cell can still sustain a high photovoltaic power conversion efficiency of 19.38%. By virtue of the shared electrode circuit design, the raindrop solar cell can continue to purvey electric power on rainy and sunny days, and it only takes about 175 s to charge a 2.2 µF capacitor to 5 V.
RESUMEN
Environmentally-friendly, cyanidin(Cy)-based anthocyanin isolated from red-cabbage served as a spectroscopic probe imprinted onto chitosan nanoparticles (CsNPs), which were in turn integrated onto cellulose paper strip (CPS) as a host matrix to develop a metallochromic solid state sensor for real-time selective determination of ferric ions in an aqueous medium. The ferric transition metal ions in aqueous environments were detected using a novel, simple, portable, fast responsive, low-cost, real-time, environmentally safe, reversible and colorimetric sensor based on chitosan nanoparticles as a hosting biopolymer and cyanidin phenol chromophore as a biomolecular probe. In order to use the cyanidin biomolecule as a pH indicator and chelating agent, it was purified from red-cabbage and added into the CsNPs biosensor film. The colorimetric shift increased in direct proportion to the ferric ion concentration. As a result, the current research that was both qualitative and quantitative was carried out. While the Cy-CsNPs-CPS sensor showed high selectivity for ferric ions, no color change was detected for other metal cations. It was discovered that the detection process occurred as a result of a coordination complex formed between the active sites of phenolic cyanidin and Fe(III) ions.
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Brassica , Quitosano , Nanopartículas , Antocianinas/química , Brassica/química , Celulosa/química , Compuestos Férricos , Extractos VegetalesRESUMEN
Photochromic and long-lasting photoluminescent transparent, rigid, ultraviolet (UV) protective and superhydrophobic poly(methyl methacrylate) (PMMA) plastic able to switch colour beneath UV irradiation was developed. Photoluminescent transparent PMMA plastic was prepared by the simple polymerization process of methyl methacrylate immobilized with alkaline earth aluminate (AEA) nanoparticles. These colourless PMMA plastic substrates showed a colour switch to greenish underneath UV light as proved using CIELAB screening. The morphology of AEA was evaluated using transmission electron microscopy. Conversely, transparent PMMA samples were evaluated using energy-dispersive X-ray spectra, scanning electron microscope, X-ray fluorescence spectroscopy and for hardness properties. Additionally, the photoluminescence properties were explored by studying excitation and emission spectra. The produced luminescence colourless PMMA plastic substrates displayed excitation band at 370 nm, and three emission peaks at 433, 494 and 513 nm. Photoluminescent PMMA with lower contents of AEA showed fast and reversible photochromism under UV light, while PMMA samples with higher contents of AEA showed long-lasting luminescence such as a flashlight with the ability to replace electric power. The findings showed that the produced photoluminescence colourless PMMA plastic substrates exhibited enhanced UV shielding and superhydrophobicity.
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Nanopartículas , Polimetil Metacrilato , Luminiscencia , PolimerizacionRESUMEN
Novel fluorescent nanofibres were developed via the electrospinning of chromophore-doped cellulose. Two different perylene-doped cellulose fluorescent fibres were fabricated using cellulose as a host material and perylene dye derivatives as active dopants. Fluorescent cellulose nanofibres were prepared via the electrospinning technique using two different perylene dyes, including perylene diimide and perylene mono-imide sodium/potassium salts. The generated fluorescent silica nanoparticles exhibited diameters varying in the range 80-180 nm. The generated electrospun fluorescent nanofibrous structures displayed smooth surfaces with average diameters of 200-300 nm for cellulose comprising perylene diimide and sodium/potassium salts of perylene mono-imide dyes, respectively, dispersed uniformly in the cellulose matrix. The generated fluorescent nanoparticles and nanofibres were characterized by different standard methods, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescent optical microscope (FOM) and Fourier-transform infrared spectra (FT-IR). The fluorescence properties of the fabricated cellulose nanofibres were explored. Those fluorescent nanofibres pave the way for the development of promising textile fluorescence materials, such as flexible displays, photonics, and optical devices.
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Nanofibras , Nanopartículas , Perileno , Celulosa , Colorantes , Electrónica , Dióxido de Silicio , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Photochromism has been applied as an interesting technique in order to improve the anticounterfeiting of commercial commodities. To build up a mechanically reliable anticounterfeiting nanocomposite, it has been vital to enhance the engineering process of the anticounterfeiting material. In the current study, we developed mechanically reliable and highly photoluminescent lanthanide-doped strontium aluminate nanoparticles (LSAN)/polyacrylonitrile (PAN) hybrid nanofibres successfully fabricated using an electrospinning technique for anticounterfeiting applications. The produced nanocomposite films exhibited ultraviolet-induced photochromic anticounterfeiting properties. To guarantee the transparency of the LSAN-PAN film, LSAN must be immobilized onto the nanoparticle size to allow better dispersion without aggregation in the polyacrylonitrile matrix. The LSAN-PAN nanofibrous film demonstrated absorbance intensity that exhibited at 354 nm and associated with an emission intensity at 424 nm. The produced LSAN-PAN films demonstrated an enhanced hydrophobicity when increasing the ratio of LSAN, without adversely influencing their native appearance and mechanical performance. Upon excitation with ultraviolet light, the translucent nanofibrous substrates exhibited fast and reversible photochromic activity to greenish-yellow without exhaustion. The nanofibrous films exhibited stretchability, transparency, flexibility, and ultraviolet light-induced photochromism at low cost. The current strategy can be considered as an efficient technique towards the development of various anticounterfeiting materials for a better market with economic and social values.
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Elementos de la Serie de los Lantanoides , Nanofibras , Nanopartículas , Resinas Acrílicas , Luminiscencia , EstroncioRESUMEN
There have been strong demands for nanofibrous scaffolds fabricated by electrospinning for various fields due to their various advantages. Electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibre mats were prepared. The effects of processing variables as well as the inclusion of poly(ethylene glycol) (PEG) on the morphologies of generated fibres were investigated using Fourier-transform infrared spectroscopy and scanning electron microscopy. The average fibrous diameter was monitored in the range 400-3000 nm relying on the total content of PEG. The fluorescence cell imaging of electrospun mats was also explored. The results of cell viability demonstrated that skin fibroblast BJ-1 cells showed different adhesions and growth rates for the three kinds of PHBV fibres. Electrospun PHBV mats with low amount of PEG offer a high-quality medium for cell growth. Therefore, those mats exhibited high potential for soft tissue engineering, in particular wound healing.
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Nanofibras , Ingeniería de Tejidos , Ácido 3-Hidroxibutírico , Proliferación Celular , Hidroxibutiratos , Poliésteres , PolietilenglicolesRESUMEN
Multifunctional fibrous surfaces with ultraviolet protection, self-cleaning, or antibacterial activity have been highly attractive. Nanocomposites consisting of silver (AgNPs) and titanium dioxide (TiO2 NPs) nanoparticles (Ag/TiO2) were developed and coated onto the surface of viscose fibers employing a straightforward pad-dry-cure procedure. The morphologies and elemental compositions were evaluated by scan electron microscopy (SEM), infrared spectra (FTIR), and energy-dispersion X-ray spectra (EDS). The resultant multifunctional textile materials displayed antibacterial and photo-induced catalytic properties. The photocatalyzed self-cleaning properties were investigated employing the photochemical decay of methylthioninium chloride, whereas the antibacterial properties were studied versus E. coli. The viscose fibers coated with Ag/TiO2 nanocomposite demonstrated improved efficiency compared with viscose fibers coated with pure anatase TiO2 nano-scaled particles.
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Herein, we develop a novel smart cotton swab as a diagnostic assay for onsite monitoring of sweat pH changes toward potential applications in monitoring human healthcare and drug exam. Anthocyanin (Ac) can be extracted from Brassica oleracea var. capitata f. rubra using a simple procedure. Then, it can be used as a direct dye into cotton fibers using potash alum as mordant (M) to fix the anthocyanin dye onto the surface of the cotton fabric (Cot). This was monitored by generating mordant/anthocyanin nanoparticles (MAcNPs) onto the fabric surface. The cotton sensor assay demonstrated colorimetric changes in the ultraviolet-visible absorbance spectral analysis associated with a blueshift from 588 to 422 nm with increasing the pH of a perspiration simulant fluid. The biochromic performance of the dyed cotton diagnostic assay depended essentially on the halochromic activity of the anthocyanin spectroscopic probe to demonstrate a color change from pink to green due to intramolecular charge transfer occurring on the anthocyanin chromophore. After dyeing, no significant defects were detected in air-permeability and bend length. High colorfastness was investigated for the dyed cotton fabrics.
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Antocianinas/química , Bioensayo , Colorimetría/métodos , Fibra de Algodón , Tecnología Química Verde , Sudor/fisiología , Color , Gases , Concentración de Iones de Hidrógeno , Nanopartículas/ultraestructura , Permeabilidad , Espectrofotometría UltravioletaRESUMEN
A smart photoluminescent nanocomposite surface coating was prepared for simple industrial production of long-persisting phosphorescence and superhydrophobic wood. The photoluminescent nanocomposite coatings were capable of continuing to emit light in the dark for prolonged time periods that could reach 1.5 h. Lanthanide-doped aluminium strontium oxide (LASO) nanoparticles at different ratios were immobilized in polystyrene (PS) and developed as a nanocomposite coating for wood substrates. To produce transparency in the prepared nanocomposite coating, LASO was efficiently dispersed in the form of nanoscaled particles to ensure homogeneous dispersion without agglomeration in the PS matrix. The coated wood showed an absorption band at 374 nm and two emission bands at 434 nm and 518 nm. The luminescence spectra showed both long-persisting phosphorescence as well as photochromic fluorescence relying on the LASO ratio. The improved superhydrophobicity and resistance to scratching of the coated wood could be attributed to the LASO NPs incorporated in the polystyrene matrix. Compared with the uncoated wood substrate, the coated LASO-PS nanocomposite film also displayed photostability and high durability. The current study demonstrated the potential high-scale manufacturing of smart wood for some applications such as safety directional signs in buildings, household products, and smart windows.
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Nanocompuestos , Madera , Interacciones Hidrofóbicas e Hidrofílicas , Luminiscencia , EstroncioRESUMEN
Transparent wood with multifunctional properties has recently attracted more attention as an efficient building product. Here, we describe the development of transparent wood with long-persistent phosphorescence, tough surface, high durability, photostability, and reversibility without fatigue, and with ultraviolet shielding, superhydrophobicity, and flame-retardant activity. This long-persistent phosphorescent, or glow-in-the-dark, smart wood exhibited an ability to continue emitting light for prolonged periods of time. The photoluminescent translucent wooden substrate was prepared by immobilizing lignin-modulated wooden bulk with an admixture of methylmethacrylate (MMA), ammonium polyphosphate (APP), and lanthanide-doped strontium aluminate (LSA; SrAl2 O4 :Eu2+ ,Dy3+ ) phosphor nanoparticles. The photoluminescent transparent wood displayed a colour switch from colourless to bright white beneath ultraviolet (UV) light and greenish-yellow in the dark as reported by Commission Internationale de l'Éclairage laboratory colorimetric space coordinates. The generated phosphorescent wooden substrates demonstrated an absorbance band at 365 nm and an emission band at 516 nm. The phosphorescent transparent wood was improved flame-retardant properties, ultraviolet shielding, and superhydrophobic properties, as well as a reversible long-persistent phosphorescent responsiveness to UV light without fatigue. The current approach demonstrated a potential large-scale production strategy for multifunctional transparent wooden substrates for a range of applications such as smart windows, gentle indoor and outdoor lighting, and safety directional signs in buildings.
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Retardadores de Llama , Madera , Interacciones Hidrofóbicas e Hidrofílicas , Luminiscencia , EstroncioRESUMEN
New 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.