Search Results (150)

In this study, four types of anti-ultraviolet aging agents—layered double hydroxides (LDHs), organic montmorillonite (OMMT), titanium dioxide (TiO₂), and ultraviolet absorber (UV326)—were employed to modify asphalt. The modified asphalt samples underwent Rolling Thin Film Oven Test (RTFOT) and xenon-lamp aging treatments, and we examined the evolution of their physical properties, rheological performance, and chemical composition. A principal component analysis (PCA) model built on representativeness, discriminative power, and non-redundancy reduced the multidimensional data to two principal components, which together captured 87.540% of the total variance. The dynamic principal component trajectories, plotted from the reduced-dimension data for the unaged–short-term-aged–xenon-lamp-aged process, revealed that anti-aging agents sharing the same protection mechanism led to comparable rates of high- and low-temperature performance deterioration during xenon-lamp aging, whereas agents with different mechanisms resulted in distinctly different patterns of performance deterioration. In the critical xenon-lamp aging stage, the neat asphalt exhibited a trajectory vector change of ΔPC1 = 0.92 and ΔPC2 = 1.25, corresponding to an angle of 54°, reflecting a low-temperature degradation. By contrast, the physical shielding agents LDHs and OMMT produced much steeper trajectories with angles of approximately −80°, where ΔPC2 values rose to as high as 3.67 and 2.19 respectively despite modest reductions in overall aging. The reflective agent TiO₂ showed a more moderate angle of 84°, with ΔPC1 and ΔPC2 values of 0.16 and 1.45, indicating a slight retardation of high-temperature performance loss. Notably, the UV absorber UV326 maintained the same trajectory angle of 56° as the neat asphalt but with reduced magnitudes of ΔPC1 = 0.63 and ΔPC2 = 0.94, suggesting a balanced delay in aging without altering its relative progression. This study proposes a novel analytical framework for mechanism-based clustering analysis and the precise selection of anti-aging agents for asphalt. Full article

Although optical fiber-based surface plasmon resonance (SPR) sensors have revolutionized real-time, label-free biosensing, conventional designs suffer from limited multi-analyte detection capabilities. This study utilizes the novel Pi (π)-configured dual SPR optical fiber sensor with two opposing side-polished surfaces, enabling plasmonic excitation for simultaneous multi-analyte detection. The proposed sensor leverages asymmetric metallic thin films such as Ag, Au, Cu, and hybrid configurations (metal + TiO₂) to generate two distinct resonance peaks, significantly enhancing detection versatility. Numerical simulations using the finite element method in COMSOL Multiphysics v6.3 demonstrate that the π-configuration achieves dual resonance dips at 982 nm and 1276 nm for Ag and Ag–TiO₂ films, 1040 nm and 1317 nm for Au and Au–TiO₂ films, and 977 nm and 1249 nm for Cu and Cu–TiO₂ films, respectively, for an analyte refractive index of 1.42. A peak spectral separation >125 nm was achieved for all the sensors for a refractive index range of 1.37–1.42, ensuring that the two dips are resolvable since the change in SPR wavelength is greater than or equal to the full width at half maximum, preserving dual-analyte capability and minimizing potential crosstalk. The results indicate that the π-configured dual SPR sensor utilizing silver and silver–TiO₂ sensing layers had the highest wavelength sensitivity of 12,600 nmRIU⁻¹ and 20,000 nmRIU⁻¹, respectively, slightly outperforming its gold and copper counterpart. The optimized metallic and hybrid nanostructured films ensure dual distinct peaks with high sensitivity, while maximizing refractive index resolution. This work presents the design of a π-configured SPR-based optical fiber sensor utilizing dielectric and multi-metallic thin films, thereby offering a breakthrough in multiplexed biosensing for applications in medical diagnostics, environmental monitoring, and chemical detection. Full article

Long-gap esophageal atresia is a congenital anomaly that requires challenging repair procedures that are often associated with complications. This work proposes the use of nitinol to repair long-gap esophageal atresia. A first proof-of-concept with commercial nitinol is presented. Experimental tests and simulations were performed, including the application of electrical currents to promote nitinol heating and consequent contraction, tensile tests, chemical analysis, and ex vivo tests using porcine esophageal tissues. A preliminary experiment is also presented regarding NiTi sputtering deposition and the morphological, chemical, and crystallographic analysis of the thin-films, featuring the implementation of a microfabricated solution. The experimental electrical tests were in accordance with the simulations. The nitinol electrical resistance (0.8–1.5 Ω) decreased as its temperature increased (20–60 °C) with the application of electrical current (<1 A), which was consistent with the experimental Seebeck coefficient (6.49 ± 0.46 µV/K). The measured forces (6.5 N at 45 °C) are also in accordance with traction sutures. Chemical analysis revealed a passive titanium dioxide layer reported for nitinol. Regarding the ex vivo tests, the average nitinol final length was 28.5 mm, below 30 mm (threshold for long-gap esophageal atresia). Finally, preliminary results from NiTi sputtering confirmed well-controlled deposition and the viability of scaling this approach, opening new avenues for nitinol-based biomedical devices. Full article

Traditional nano-titanium dioxide films have strong photocatalytic performance; however, their hydrophilic surfaces make it easier for pollutants or by-products resulting from the reaction processes to deposit on the membrane surface and occupy their active sites, which reduces the coating degradation efficiency and shortens their service life. In the current study, nano-TiO₂ was mixed with SiO₂ for hydrophobic film coating by the sol–gel method. The surface morphology of the membrane was observed by scanning electron microscopy (SEM), the composition of the coating was analyzed by X-ray diffraction (XRD), and its stable hydrophobicity was verified by contact angle testing (θ_w = 117°). The specific surface area Brunauer–Emmett–Teller (BET) revealed between 0.0561 (for 3 layers) and 0.0868 m²/g after 9 layers of coating. Through establishing a simplified photocatalytic reactor under UV, the new coating’s abilities in the degradation of methylene blue, its anti-fouling, and durability were examined. Results revealed that when the common TiO₂ films were combined with hydrophobic films, nearly 100% of methylene blue was degraded, and the degradation capacity remained stable after three rounds of tests. Moreover, it was observed that only a small amount of methylene blue adhered to the new film surface comparatively. Outcomes confirmed that the SiO₂-mixed TiO₂ thin films exhibited enhanced hydrophobicity. When integrated with ordinary TiO₂ coatings, the composite structure demonstrated superior photocatalytic efficiency and stability in the degradation of aqueous pollutants compared to pure TiO₂ coatings. Full article

Background/Objective: Photocatalytic oxidation is often interpreted as evidence of microplastic degradation, yet whether surface chemical modification under dry conditions corresponds to meaningful bulk polymer breakdown remains unclear. To help fill that gap, this study investigates the concentration-dependent photocatalytic aging of polystyrene (PS) microplastics incorporated into Titanium dioxide-coated hollow glass microsphere (TiO₂–HGM) composites under solid-state UV irradiation, with emphasis on distinguishing surface oxidation from bulk degradation. Methods: Thin-film composites containing 1 wt%, 5 wt%, and 10 wt% TiO₂–HGMs were exposed to UV-A irradiation (365 nm) for 183.5 h under dry conditions. Chemical and structural changes were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and UV–visible spectroscopy. The carbonyl index (CI) was calculated from baseline-corrected integrated absorbance areas relative to an invariant aromatic reference band. Results: CI values increased from 0.483 (1 wt%) to 0.702 (5 wt%) and slightly decreased to 0.645 (10 wt%), indicating non-linear oxidation behavior and partial saturation. XPS showed a corresponding rise in the O/C ratio from 0.42 to 0.51. In contrast, UV–visible spectra exhibited minimal changes in aromatic absorption. Conclusions: Increasing photocatalyst concentration enhances surface oxidation but does not induce proportional bulk polymer degradation under solid-state conditions. Full article

Titanium dioxide (TiO₂) thin films were deposited by DC magnetron sputtering and subsequently treated in hot water at 50, 70, and 95 °C for 72 h to investigate the influence of low temperature on their structural optical and functional properties. XRD analysis revealed a progressive transformation from amorphous to anatase phase with increasing treatment temperature, accompanied by an increase in crystallite size from 5.2 to 15.1 nm. FT-IR spectroscopy confirmed enhanced surface hydroxylation and contact angle measurements showed a decrease from 77.4° to 19.7°, indicating a significant improvement in superior wettability. The transmittance spectroscopy revealed a slight narrowing of the optical band gap from 3.34 to 3.21 eV, consistent with improved visible-light absorption. Photocatalytic tests using the Resazurin indicator demonstrated that the film treated at 95 °C exhibited the highest activity, achieving a bleaching time of 245 s three times faster than treated at 50 °C and twice as fast as treated at 70 °C. Under low-intensity solar irradiation, the same sample achieved complete E. coli inactivation within 90 min. These improvements are attributed to increased crystallinity, surface hydroxyl density, and enhanced ROS generation. Overall, this study demonstrates that mild hot-water treatment is an effective, substrate-friendly route to enhance TiO₂ film wettability and multifunctional performance, enabling the fabrication of self-cleaning and antibacterial coatings on fragile materials such as plastics and textiles. Full article

Electrolysis and biological processes, such as fermentation and microbial electrolysis cells, offer efficient hydrogen production alongside wastewater treatment. This study presents a novel microbial electrolyzer (ME) comprising a titanium dioxide (TiO₂) anode, a nickel–iron–carbon (NiFeC) cathode, and a cellulose nanocrystal proton exchange membrane (CNC-PEM) designed to generate hydrogen from palm oil mill effluent (POME). The system is powered by a 12 V electric double-layer organic supercapacitor (EDLOSC) integrated with a ZnO/PVA-based solar thin film. Power delivery to the TiO₂-NiFeC-PEM electrolyzer is optimized using an Adaptive Neuro-Fuzzy Inference System (ANFIS). Laboratory-scale pilot tests demonstrated effective degradation of POME’s organic content, achieving a hydrogen yield of approximately 60%. Additionally, the nano-structured ZnO/CuO–ZnO/PVA solar film facilitated stable power supply, enhancing in situ hydrogen production. These results highlight the potential of the EDLOSC-encased ZnO/PVA-powered electrolyzer as a sustainable solution for hydrogen generation and industrial wastewater treatment. Full article

This study evaluated the combined incorporation of zinc oxide (ZnO) and titanium dioxide (TiO₂) nanoparticles into a styrene–butadiene–styrene (SBS) copolymer-modified asphalt binder, aiming to increase thermal conductivity and healing potential while maintaining rheological performance. Nanocomposites containing ZnO + TiO₂ (50/50 wt.%) were produced at dosages of 2–12 wt.% and subjected to the Rolling Thin Film Oven Test (RTFOT), thermal conductivity measurements, viscosity testing, and rheological characterization. A dense-graded asphalt mixture with the optimized dosage was evaluated through wheel-tracking, four-point bending fatigue and healing, and internal heating rate assessment under microwave radiation. The integrated results indicated 8.5 wt.% as the optimal dosage, providing a 106.3% increase in thermal conductivity and improving the high-temperature performance grade (PGH) from 76-XX to 82-XX. Non-recoverable creep compliance (Jnr) decreased by 21.1%, and viscosity at 135 °C increased by 41.8%, remaining below 3.0 Pa·s. In the asphalt mixture, healing capacity increased by 50.7%, and the internal heating rate by 50.0%, while the wheel-tracking rut depth decreased by 13.3%. These findings demonstrate that 8.5 wt.% ZnO + TiO₂ simultaneously enhances heat conduction, healing efficiency, and resistance to permanent deformation, offering a promising solution for pavements subjected to high temperatures and heavy traffic. Full article

Titanium dioxide (TiO₂) is an important semiconductor material widely used in both fundamental studies and technological applications. Herein, TiO₂ nanorod thin film coatings were fabricated on transparent conductive fluorine-doped tin oxide (FTO) substrates using a hydrothermal synthesis approach, followed by annealing at various temperatures. The effects of annealing temperatures on the Raman and optical absorption spectra were systematically investigated to elucidate the behavior of Raman-active lattice vibrations and optical transitions. As the annealing temperatures increased, both the full width at half maximum of the Raman vibrational modes and the band gap of the TiO₂ nanorod thin films decreased. These trends indicate enhanced crystallinity and phonon lifetimes at higher annealing temperatures. The longer phonon lifetimes contribute to reduced electron–hole recombination, while the narrower band gap extends the optical absorption range into the visible region. This study provides valuable insights into the relationship between annealing temperatures and the structural, vibrational and optical properties of rutile TiO₂ nanorod thin film coatings, highlighting their potential for improved performance in photoelectrocatalytic and optoelectronic applications. Full article

Titanium dioxide (TiO₂) thin films sensitized with curcumin were fabricated to investigate the influence of sensitization on their spectroscopic, optical, and photocatalytic properties. TiO₂ films were prepared using different curcumin concentrations and characterized by FTIR, UV–Vis, and diffuse reflectance spectroscopy (DRS). The adsorption kinetics of curcumin on TiO₂ were analyzed, and the photocatalytic performance was evaluated through methylene blue (MB) photodegradation under visible-light irradiation. FTIR spectra confirmed the successful anchoring of curcumin onto the TiO₂ surface, while optical characterization revealed a significant enhancement in visible-light absorption. The band gap decreased from 3.2 eV (pure TiO₂) to 1.8 eV (curcumin-sensitized TiO₂). Furthermore, the curcumin adsorption onto semiconductor data fitted the pseudo-second-order kinetic model, yielding a maximum adsorption capacity of 12.0 mg·g⁻¹. Density Functional Theory (DFT) calculations indicated that ligand-to-metal charge transfer (LMCT) transitions are responsible for the improved visible-light response. Photocatalytic tests demonstrated that all curcumin-sensitized TiO₂ films were active under visible irradiation, confirming curcumin as an effective natural sensitizer for enhancing TiO₂-based photocatalytic coatings. Full article

Photocatalytic pathogen inactivation is gaining increasing importance due to the rising number of microbial species resistant to conventional antibacterial agents. Titanium dioxide (TiO₂)-based photocatalysts have emerged as a promising solution, being not only potent antibacterial agents but also environmentally friendly and capable of simultaneously degrading organic pollutants. This review summarizes recent advances in the antibacterial performance of different TiO₂ modifications, including commercial nanopowders, nanoparticles with various morphologies, thin films, composites, and polymer-supported nanostructures, all primarily activated under UV light. Given the limited ability of pristine TiO₂ to harvest solar radiation, we also highlight the most recent strategies for designing visible-light-responsive TiO₂, such as doping, incorporation of plasmonic metal nanoparticles, formation of heterostructures, and interfacial charge transfer complexes. In addition, we discuss the fundamental structural features of TiO₂, the mechanisms of reactive oxygen species (ROS) generation involved in bacterial inactivation, and kinetic models describing antibacterial efficiency. These insights aim to advance the understanding and development of eco-friendly, cost-effective, and sustainable photocatalytic disinfection technologies. Full article

This study addresses the need for efficient photoelectric materials by fabricating Indium-doped tin sulfide (SnS-In)/titanium dioxide (TiO₂) heterostructure thin films via radio frequency (RF) magnetron sputtering. We systematically investigated the synergistic enhancement of photoelectric properties from both In-doping and the heterostructure design. SnS-In films with controlled In concentrations were prepared by embedding varying numbers of indium pellets into the SnS sputtering target. Our findings reveal that an optimal In doping of 4.93 at% significantly improves the crystalline quality and light absorption of SnS, reducing its band gap from 1.27 eV to 1.13 eV and enhancing carrier concentration and mobility. Subsequently, the optimized SnS-In film combined with TiO₂ formed a heterojunction, achieving a peak photocurrent density of 6.36 µA/cm² under visible light. This is 2.2 and 53.0 times higher than standalone SnS-In and TiO₂ films, respectively. This superior performance is attributed to the optimal In³⁺ doping effectively modulating the SnS band structure and the type-II heterojunction promoting efficient charge separation. This work demonstrates a promising strategy for optoelectronic conversion and photocatalysis by combining In-doping for SnS band structure engineering with TiO₂ heterostructure construction. Full article

In this study, tin oxide (SnO₂) resistive random-access memory (RRAM) thin films were fabricated using the thermal evaporation and radiofrequency and dc frequency sputtering techniques for metal–insulator–metal (MIM) structures. The fabrication process began with the deposition of a silicon dioxide (SiO₂) layer onto a silicon (Si) substrate, followed by the deposition of a titanium nitride (TiN) layer to serve as the bottom electrode. Subsequently, the tin oxide (SnO₂) layer was deposited as the resistive switching insulator. Two types of top electrodes were developed to investigate the influence of different oxygen concentrations on the bipolar switching, electrical characteristics, and performance of memory devices. An aluminum (Al) top electrode was deposited using thermal evaporation, while a platinum (Pt) top electrode was deposited via dc sputtering. As a result, two distinct metal–insulator–metal (MIM) memory RRAM device structures were formed, i.e., Al/SnO₂/TiN/SiO₂/Si and Pt/SnO₂/TiN/SiO₂/Si. In addition, the symmetry bipolar switching characteristics, electrical conduction mechanism, and oxygen concentration factor of the tin oxide-based memory devices using rapid thermal annealing and different top electrodes were determined and investigated by ohmic, space-charge-limit-current, Schottky, and Poole–Frenkel conduction equations in this study. Full article

In this study, lanthanum–nitrogen co-doped titanium dioxide (La-N-TiO₂) thin films were fabricated using Ion Beam Assisted Deposition (IBAD) and subjected to accelerated ultraviolet (UV) aging experiments to systematically investigate the impact of co-doping on the films’ resistance to UV aging. X-ray diffraction (XRD) analysis revealed that La-N co-doping inhibits the phase transition from anatase to rutile, significantly enhancing the phase stability of the films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations indicated that co-doping increased the density and surface uniformity of the films, thereby delaying the expansion of cracks and increase in roughness induced by UV exposure. Energy-dispersive X-ray spectroscopy (EDS) results confirmed the successful incorporation of La and N into the TiO₂ lattice, enhancing the chemical stability of the films. Contact angle tests demonstrated that La-N co-doping markedly improved the hydrophobicity of the films, inhibiting the rapid decay of hydrophilicity during UV aging. After three years of UV aging, the co-doped films maintained high structural integrity and photocatalytic performance, exhibiting excellent resistance to UV aging. These findings offer new insights into the long-term stability of photovoltaic self-cleaning materials. Full article

This study examines the intrinsic optical enhancements of carbon fiber-reinforced polymers (CFRPs) achieved through the integration of magnesium oxide (MgO) nanoparticles, as well as Mg/MgO and titanium dioxide (TiO₂) thin films onto carbon fibers. Integration was performed by quasi-continuous electrophoretic deposition (EPD) and physical vapor deposition (PVD), respectively. Employing a customized electrophoretic cell, EPD facilitated uniform MgO nanoparticle deposition onto unsized carbon fibers, ensuring stable nanoparticle dispersion and precise fiber coating. As a result, the fibers exhibited increased ultraviolet (UV) reflectance, largely attributed to the optical properties of the protective MgO layer. In parallel, PVD enabled the deposition of Mg/MgO and TiO₂ thin films with tailored thicknesses, providing precise control over key optical parameters such as reflectivity and interference effects. Mg/MgO coatings demonstrated high UV reflectivity, while TiO₂ layers, with their varying refractive indices, generated vibrant colors in the visible (Vis) range through thickness-dependent light interference. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) assessed the quality, thickness, and uniformity of these thin films, and UV/Vis spectroscopy confirmed the influence of deposition parameters on the resulting optical performance. Post-lamination analyses revealed that both EPD and PVD modifications significantly enhanced UV reflectivity and allowed for customizable color effects. This dual strategy underscores the potential of combining EPD and PVD to develop advanced CFRPs with superior UV resistance, decorative optical features, and improved environmental stability. Full article