Search Results (27)

In a recent investigation the corrosion-fighting potential of five benzaldehyde derivatives were explored: 4-Formylbenzonitrile (BA1), 4-Nitrobenzaldehyde (BA2), 2-Hydroxy-5-methoxy-3-nitrobenzaldehyde (BA3), 3,5-Bis(trifluoromethyl)benzaldehyde (BA4), and 4-Fluorobenzaldehyde (BA5). Benzaldehyde derivative (BA-2) showed a maximum inhibition efficiency of 93.3% at 500 ppm. Several techniques were used to evaluate these compounds’ ability to protect mild steel from corrosion in a 1 M HCl solution, including potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), adsorption isotherms, and computational methods. Supporting techniques Fourier transform infrared spectroscopy (FTIR) and ultraviolet–visible (UV-Vis) spectroscopy were also employed to validate the results. Despite sharing a common benzene ring, the molecules differ in their substituents, allowing for a comprehensive examination of the substituents’ impact on corrosion inhibition. PDP analysis disclosed that the inhibitors exhibited mixed-type inhibition behavior, interacting with anodic as well as cathodic reactions, influencing the corrosion process. EIS analysis revealed that benzaldehyde derivatives formed a protective passive film on the metal, exhibiting high corrosion resistance by shielding the alloy from corrosive attacks. The benzaldehyde inhibitors followed the Langmuir adsorption isotherm, with high R² values near one, indicating a monolayer adsorption mechanism. DFT results indicate that BA 2 is the most effective inhibitor. FTIR and UV-vis spectroscopy revealed the molecular interactions between metal and benzaldehyde derivative molecules, providing insight into the binding mechanism. Experimental results support the outcomes obtained from the molecular dynamic (MD) simulations. Full article

Cesium tungsten bronzes (Cs_xWO₃), as functional materials with excellent near-infrared shielding properties, demonstrate significant potential for applications in smart windows. However, traditional synthesis methods, such as solid-state reactions and solvothermal/hydrothermal approaches, typically require harsh conditions, including high temperatures (above 200 °C), high pressure, inert atmospheres, or prolonged reaction times. In this study, we propose an optimized microwave-assisted solvothermal synthesis strategy that significantly reduces the severity of reaction conditions through precise parameter control. When benzyl alcohol was employed as the solvent, Cs_xWO₃ nanoparticles could be rapidly synthesized within a relatively short duration of 15 min at 180 °C, or alternatively obtained through 2 h at a low temperature of 140 °C. However, when anhydrous ethanol, which is cost-effective and environmentally friendly, was substituted for benzyl alcohol, successful synthesis was also achieved at 140 °C in 2 h. This method overcomes the limitations of traditional high-pressure reaction systems, achieving efficient crystallization under low-temperature and ambient-pressure conditions while eliminating safety hazards and significantly improving energy efficiency. The resulting materials retain excellent near-infrared shielding performance and visible-light transparency, providing an innovative solution for the safe, rapid, and controllable synthesis of functional nanomaterials. Full article

This study aims to investigate the structural, spectroscopic, and electronic properties of the synthetic missile fuel exo- and endo-tetrahydrodicyclopentadiene (THDCPD, JP-10) using density functional theory (DFT). It is to understand the dominance of the liquid exo-isomer (96%) of the jet fuel from the subtle differences between the isomers. The present DFT calculations reveal that the exo-isomer is 15.51 kJ/mol more stable than the endo-isomer, attributed to the flipping of the triangular ΔC8-C10-C9 ring in its norbornane skeleton. Calculated nuclear magnetic resonance (¹³C-NMR) and infrared (IR) spectra, validated by experimental data, reveal larger chemical shifts for junction carbons (C1/C2 and C3/C4) due to reduced electron shielding and show distinct vibrational patterns. Charge analysis indicates that all carbon atoms are negatively charged except for the C1/C2 carbons which are positively charged in both isomers. While overall IR spectra of the isomers appear similar, bands near 3000 cm⁻¹ correspond to distinctly different vibrational modes. The exo-isomer’s electronic structure features a more delocalized HOMO and a larger HOMO-LUMO gap (7.63 eV) than the endo-isomer (7.37 eV). All such differences contribute to the properties of exo-THDCPD and, therefore, why the exo-isomer dominates JP-10 fuel. Full article

This study is dedicated to the development of a new type of cesium tungsten bronze energy-saving laminated glass and explores its application in insulating glass combinations, offering innovative ideas and practical solutions for advancing energy-saving glass technology. Experimental results show that both Cs_xWO₃ (CWO) dispersions exhibit good visible light transmittance and near-infrared shielding properties, with CWO1 demonstrating superior shielding in the 650–950 nm range, attributed to differences in shape and size distribution and verified by simulations using the Drude–Lorentz model and the finite element method. Full article

Far infrared radiation (FIR) within the wavelength range of 4–14 μm can offer human health benefits, such as improving blood flow. Therefore, additives that emit far infrared radiation have the potential to be incorporated into polymer/fabric matrices to develop textiles that could promote health. In this study, biochar derived from candlenuts and pyrolyzed with activated carbon (AC) was incorporated into polypropylene (PP) films and investigated for its potential as a health-promoting textile additive. The properties of biochar were compared with other far infrared (FIR) emitting additives such as hematite, Indian red ochre, and graphene. The addition of biochar increased FIR emissivity to 0.90, which is 9% higher than that of pristine PP. Additionally, biochar enhanced UV and near-infrared (NIR) blocking capabilities, achieving an ultra-protection factor (UPF) of 91.41 and NIR shielding of 95.85%. Incorporating 2 wt% biochar resulted in a 3.3-fold higher temperature increase compared to pristine PP after 30 s of exposure to an FIR source, demonstrating improved heat retention. Furthermore, the ability to achieve the lowest thermal effusivity among other additives supports the potential use of biochar-incorporated fabric as a warming material in cold climates. The tensile properties of PP films with biochar were superior to those with other additives, potentially contributing to a longer product lifespan. Additionally, samples with red ochre exhibited the highest FIR emissivity, while samples with hematite showed the highest capacity for UV shielding. Full article

Cs_0.33WO₃ (CWO) is a widely used inorganic material in window films and glass coatings, known for its excellent near-infrared radiation (NIR) blocking property and high visible light transmittance (T_vis). However, the stability of NIR blocking and the optical properties of CWO in the process of application is an urgent and important problem, because significant changes in optical results can impact the related products, such as window films, glass coatings, and so on. In this paper, the particle sizes and optical properties of CWO are tested to study the light stability and their relative relations. The results indicate that CWO particle sizes between 130 nm and 100 nm (D90, the point where 90% of the particles have a diameter smaller than the specified value) exhibit high stability in terms of NIR blocking and visible light transmittance (Tvis). CWO particles with D90 < 100 nm experience a greater reduction in NIR blocking, though this ability significantly recovers upon exposure to sunlight, making these coatings particularly suitable for use in tropical and subtropical climates. Full article

This research aims to enhance the near-infrared (NIR) shielding ability of cesium tungsten bronze (CsWO₃) by increasing the spectral absorption in this region through the incorporation of gold nanorods (Au_NR). Two approaches were used to prepare the composite materials: physical mixing and solvothermal process. The effects of gold nanorods content on the crystalline size, particle size, shape, and optical properties of the composite were investigated systematically using DLS, TEM, XRD, and UV–Vis spectroscopy techniques, respectively. The physical mixing process synergizes Au_NR and CsWO₃ into a composite which has better NIR absorption than that of neat Au_NR and CsWO₃ nanorods. A composite with 10 mol% of Au_NR shows the highest NIR absorption ability due to the surface plasmon resonance and energy coupling between Au and CsWO₃. With the solvothermal process, the CsWO₃ nanorods grow up to 4–7 microns when the Au_NR content increases to 0.8 mol% due to the incorporation of the Au atoms. The microsized CsWO₃ rods have superior NIR shielding property compared to other conditions, including the Au_NR+CsWO₃ nanocomposite with 10 mol% of Au_NR from the physical mixing process. Full article

The global antibiotic resistance crisis has drawn attention to the development of treatment methods less prone to inducing drug resistance, such as antimicrobial photodynamic therapy (aPDT). However, there is an increasing demand for new photosensitizers capable of efficiently absorbing in the near-infrared (NIR) region, enabling antibacterial treatment in deeper sites. Additionally, advanced strategies need to be developed to avert drug resistance stemming from prolonged exposure. Herein, we have designed a conjugated oligoelectrolyte, namely TTQAd, with a donor-acceptor-donor (D-A-D) backbone, enabling the generation of reactive oxygen species (ROS) under NIR light irradiation, and cationic adamantaneammonium groups on the side chains, enabling the host-guest interaction with curcubit[7]uril (CB7). Due to the amphiphilic nature of TTQAd, it could spontaneously form nanoassemblies in aqueous solution. Upon CB7 treatment, the positive charge of the cationic adamantaneammonium group was largely shielded by CB7, leading to a further aggregation of the nanoassemblies and a reduced antibacterial efficacy of TTQAd. Subsequent treatment with competitor guests enables the release of TTQAd and restores its antibacterial effect. The reversible supramolecular switch for regulating the antibacterial effect offers the potential for the controlled release of active photosensitizers, thereby showing promise in preventing the emergence of drug-resistant bacteria. Full article

We prepared cholesteric liquid crystal (CLC) films with broadband reflective properties by admixing organic dye UV-327 into inorganic zinc oxide nanoparticles (ZnO NPs), utilizing the principle of pitch distribution from a large to a small gradient along the film thickness direction, leading to broadband reflection. ZnO NPs are poorly dispersed and easy to gather, but they do not decompose easily. The addition of UV-327 makes up for the above shortcomings. UV-327 is an organic compound with good compatibility and dispersion with liquid crystal systems. Therefore, we used the method of mixing two UV-absorbing dyes (UV-327 and ZnO NPs) to obtain CLC films. UV-absorbing dyes (UV-327 and ZnO NPs) made the liquid crystal films form a UV intensity gradient in the direction of thickness, prompting the polymerizable monomers to polymerize faster on the stronger side of the light, leading to the relative diffusion of chiral molecules and polymerizable monomers, forming the concentration gradient of chiral molecules in the direction of thickness. The pitch has a gradient distribution as the chiral concentration varies. Then, anchored by the polymer network, the pitch gradient distribution no longer changes. Broadened reflective bandwidth can reach up to 881 nm. Furthermore, the film covers the near-infrared wavelength band well, which can be applied to future smart windows or laser shielding for medical and military applications. It is also believed that this achievement will optimize the preparation technology of broadband reflective CLC films in the future. Full article

To enhance the direct current (DC) dielectric properties of cross-linked polyethylene (XLPE) for high-voltage (HV) cable insulation, the polyethylene molecular chain is modified by grafting bismaleimide ethane (BMIE), which creates carrier deep traps within the polymer material. Compared to the traditional modified molecule maleic anhydride (MAH), BMIE has a significantly higher boiling point than the production temperature of XLPE. Additionally, it does not release bubbles during the production process and, thus, preserves the dielectric properties. It was proved by infrared spectroscopy and a gel content test that BMIE was successfully grafted onto the polyethylene molecular chain and had no effect on the crosslinking degree of the polymer while reducing the amount of crosslinker, thereby reducing the influence of the by-products of the decomposition of dicumene peroxide (DCP) on the electrical resistance of polymers. The analysis of DC breakdown field strength, current density, and space charge distribution at various temperatures demonstrates that grafting BMIE can greatly enhance the dielectric properties of insulation. Polar groups in the BMIE molecule create deep trap energy levels in XLPE-g-BMIE, and these trap energy levels contribute to the formation of a charged layer near the electrode, which is shielded by Coulomb potential. As a result, the charge injection barrier increases. Additionally, the presence of these polar groups reduces the mobility of charge carriers through trap-carrier scattering, effectively suppressing the accumulation of space charge within the material. First-principle calculations also confirm that bound states can be introduced as carrier traps by grafting BMIE onto polyethylene molecules. The agreement between experimental results and simulation calculations indicates that grafting BMIE to enhance the dielectric properties of polyethylene is a new and feasible research direction in the exploitation of materials for HVDC cables. Full article

A simple and efficient method for the preparation of a film with flexible characteristic and selective reflection of near-infrared light is proposed. Based on the coexistence system (PD&SLC) of polymer dispersed liquid crystals (PDLC) and polymer stabilized liquid crystals (PSLC), it combines the flexibility of PDLC with the selectively reflection of PSLC. Innovative use of step-by-step light curing to achieve microstructural differences in the three-dimensional orientation of the material is proposed. That is, the difference between PDLC and PSLC in the planar orientation, as well as the gradient distribution of cholesteric phase liquid crystal pitch in the cell thickness direction, is observed. While realizing the flexibility of the material, the function of broadening the reflection bandwidth is fulfilled. This method of preparing liquid crystal films is expected to have great potential for applications, such as flexible smart windows, infrared light shielding, and sensors. Full article

Nano-WO₃ particles are expected to find use in new shielding materials because of their significant absorption of near-infrared light in the 1400–1600 nm and 1900–2200 nm bands and high transmittance of visible light. In this study, WO₃ was ground and dispersed using high-energy ball-milling to prepare a nano-WO₃ dispersion using BYK331 as the dispersant and ethanol as the solvent. The prepared nano-WO₃ dispersion was added to a photo-curing system and cured using UV irradiation to form films. The cured films were characterized using FT-IR, SEM, XRD, and TGA. The results showed that the nano-WO₃ powder was evenly dispersed in the coating. The infrared blocking rate of the film continuously improved and the visible light transmission rate continuously decreased with increasing amounts of nano-WO₃.For the film containing 6 wt%nano-WO₃, the infrared blocking rate of the coating is 90%, the visible light transmittance is 70%, the hardness of the coating is 3B, and the adhesion is 3H. The thermal stability of the coating is also improved. Full article

Window−film−integrated, near−infrared (NIR) absorption−based nanomaterials are of great interest in terms of numerous demands to reduce energy consumption, especially in buildings and vehicles. However, the question of how to effectively manage thermal energy generated from NIR harvesting in light−absorbing materials, rather than being wasted or causing negative effects, remains challenging. Herein, hollow copper sulfide (Cu_2−xS) on colorless polyimide (PI) films, enabling them to be well−dispersed and robustly adhered, underwent in situ growth fabrication and were utilized as NIR−thermal−shielding and organic−pollutant−removal dual−function window films. Due to strong NIR absorbance, arising from the heavy hole−doping (copper cation deficiency), the Cu_2−xS/PI composite film exhibited great promise for use in the filtration of the NIR spectrum. By monitoring Cu_2−xS densities, its NIR−shielding efficiency reached 69.4%, with hundred−percent UV blocking and consistent performance within the reliability (85 °C/85%RH) tests over one week as well as 5000 bending cycles. The integration of the films into model cars and building windows exhibited excellent thermal−shielding performance upon exposure to direct sunlight. Moreover, benefiting from the distinctive distribution of Cu_2−xS, the additional thermal energy (holes) generated in NIR absorption was successfully utilized. The densely surface−confined hollow structure of Cu_2−xS on PI significantly endowed good formaldehyde catalytic capacity, with removal efficiency reaching approximately 72% within 60 min and a negligible decline after quartic reuse. These integration methodologies enable the promising fabrication of a high−performance, bifunctional window film combining thermal shielding and indoor organic pollutant removal. Full article

Nanocrystalline tungsten bronze is an excellent near-infrared absorbing material, which has a good potential application in the field of transparent heat shielding materials on windows of automobiles or buildings, but it exhibits serious instability in the actual environment, which hinders its further application. In this paper, we coated the Cs_xWO₃ nanoparticles with TiO₂ to prepare core-shell structured Cs_xWO₃@TiO₂, and its crystal structure and optical properties were studied. The results show that the surface of Cs_xWO₃ nanoparticles is coated with a layer of TiO₂ particles with the size of several nanometers, and the shell thickness can be adjusted by the amount of Ti source. The measurement of optical properties illustrates that TiO₂-coated Cs_xWO₃ exhibits good stability in actual environment, and its transparent heat shielding performance will decrease with the increase in TiO₂ shell thickness. This work provides a new route to promote the applications of tungsten bronze as heat shielding materials. Full article

Understanding the photophysical properties and stability of near-infrared fluorescent proteins (NIR FPs) based on bacterial phytochromes is of great importance for the design of efficient fluorescent probes for use in cells and in vivo. Previously, the natural ligand of NIR FPs biliverdin (BV) has been revealed to be capable of covalent binding to the inherent cysteine residue in the PAS domain (Cys15), and to the cysteine residue introduced into the GAF domain (Cys256), as well as simultaneously with these two residues. Here, based on the spectroscopic analysis of several NIR FPs with both cysteine residues in PAS and GAF domains, we show that the covalent binding of BV simultaneously with two domains is the reason for the higher quantum yield of BV fluorescence in these proteins as a result of rigid fixation of the chromophore in their chromophore-binding pocket. We demonstrate that since the attachment sites are located in different regions of the polypeptide chain forming a figure-of-eight knot, their binding to BV leads to shielding of many sites of proteolytic degradation due to additional stabilization of the entire protein structure. This makes NIR FPs with both cysteine residues in PAS and GAF domains less susceptible to cleavage by intracellular proteases. Full article