TiO2 Nanocomposite Films Research Articles

Physical characterization, biocompatibility, and antimicrobial activity of polyvinyl alcohol/sodium alginate blend doped with TiO2 nanoparticles for wound dressing applications

The ability of wound dressing materials to tackle skin pathogens colonization that is associated with open wound infections is limited. Recently, green-synthesized metal oxide nanoparticles has received a lot of attention to overcome this limitation. However, titanium dioxide nanoparticles (TiO2-NPs) exhibit exceptional antibacterial properties. In this work, several concentrations (0, 1, 3, and 5 wt.%) of TiO2 NPs prepared using Aloe vera leaf extract were added to a blend of polyvinyl alcohol and sodium alginate (PVA:SA). This nanocomposite was designed to enhance the healing process of wounds. The interaction between the PVA:SA composite and the TiO2 NPs was confirmed by FTIR. The thermal behavior of the nanocomposite films was investigated using DSC and TGA. The experimental results indicate that the glass transition temperatures of the nanocomposites increased by increasing the added amount of TiO2 NPs to be 53.7 °C (1 wt.%), 55.8 °C (3 wt.%), and 60.6 °C (5 wt.%), which were consistently lower than the glass transition temperature of the matrix material (69.6 °C). The Dynamic Mechanical Analysis was examined. The nanocomposite doped with 5 wt.% of TiO2 NPs detected a high storage modulus (21.6 × 108). Based on swelling and degradation studies, the prepared PVA:SA:TiO2 nanocomposite films have an excellent swelling rate, and the inclusion of TiO2 NPs increases the stability of the polymeric matrix. The PVA:SA:TiO2 nanocomposite films exhibited a superior antibacterial efficacy against Gram-positive bacteria such as Bacillus cereus and Staphylococcus aureus, compared to their effectiveness against Gram-negative bacteria like Escherichia coli. Moreover, the nanocomposite films were biocompatible with Human Skin Fibroblast. Therefore, the developed PVA:SA:TiO2 nanocomposite films suit wound dressing applications.

Preparation of Transparent ZIF-8/TiO2 Nanocomposite Thin Films for Photocatalytic Applications

Transparent ZIF-8/TiO2 nanocomposite thin films were prepared by a two-stage dip-coating method. TiO2 was first deposited on glass substrates by sol-gel dip-coating. Heat treatment temperature, number of layers and doping metal type/level were optimized in the first step. In the next step, ZIF-8 was grown by solvent based crystallization method on TiO2 layers. Cu, Ce, Fe or Zn doped TiO2 thin films were prepared in order to increase the photocatalytic performance of ZIF-8/TiO2 nanocomposite. The highest photocatalytic methylene blue degradation activities were obtained with the ZIF-8/TiO2 nanocomposite thin films prepared by using 1% Cu or 1% Ce doped TiO2 thin films as the substrates. Both films exhibited 19% dye removal in 1 hour under 254 nm LED light irradiation whereas the dye removal efficiencies were 36% and 29%, respectively, in 1 hour under 365 nm LED light irradiation.

Thermoelectric properties and microstructure of nanocomposite Sb-GeO2 and Sb–TiO2 thin films

This work reports on fabrication and thermoelectric properties of Sb-GeO2 and Sb–TiO2 nanocomposite thin films. The formation of nanocomposite structure includes the precipitation of Sb phase and the amorphous GeO2 or TiO2 phase. In the Sb-GeO2 nanocomposite, the formation of large rhombohedral Sb grains is observed, where monoclinic Sb are formed as intermediate phase. This contributes remarkably to the elevation of conductivity, while results in the reduction of Seebeck coefficient and power factor. Contrary, the effective inhibition of Sb crystallization caused by TiO2 leads to the smaller monoclinic and rhombohedral Sb grains with homogeneous distribution in annealed Sb–TiO2 thin film. The existence of monoclinic Sb facilitates to acquire excellent thermoelectric properties. Tiny grains within the films introduce more grain boundaries, making it possible to scatter and filter low energy carriers. This leads to high conductivity, remarkable rise of the Seebeck coefficient, and excellent power factor of 765.5 μW/mK2 at 650 K. The results demonstrate that the Sb–TiO2 nanocomposite materials with high power factor can be a candidate for thermoelectric devices.

Development of polyaniline – TiO2 nano composite films and its application in corrosion inhibition of oil pipelines

Oil and gas industries are the driving force of Oman’s economy and have a relatively diversified wealth among Gulf Cooperation Council Countries. Oil pipelines play an important role in transporting oil and gas from the wellheads to the processing facilities. Corrosion normally results in the deterioration of the pipe material with exposure to the surrounding environment and complete control of corrosion is difficult. Corrosion in oil transmission pipeline would be effectively addressed by introducing conventional corrosion control practices. Most of the conventional techniques are either less effective or too expensive in controlling the deterioration rate of the pipe materials. However, preventative measures may be taken to protect the metal surface from corrosion is a possible way to reduce corrosion. This research work aimed to develop a novel technique utilizing Polyaniline (PANI) and Titanium dioxide (TiO2) nanocomposites to assess its corrosion inhibition effect on mild steel. TiO2 was synthesized by sol-gel process. Polyaniline-Titanium dioxide (PANI/TiO2) nanocomposites were coated on mild steel specimen by dip coating technique. The coated specimen was subjected to stability studies at different environmental conditions and exposure time. The stable thin film coated specimen was employed in the corrosion inhibition studies at various processing environments. The characteristics of TiO2 nanoparticles and PANI-TiO2 thin films were analyzed using Fourier Transform Infra-Red Spectroscopy (FTIR), Energy Dispersive X-Ray analysis (EDX) and X-Ray Diffraction (XRD) and Dynamic Light scattering (DLS). Scanning Electron Microscopy (SEM) was used to visualize the surface morphology and micro structural characteristics of the preformed thin layer. Potentio dynamic test, Atmosphere test and Wet/Dry tests were carried out to investigate the corrosion behaviour of coated and uncoated specimen. The study demonstrates that the Polyaniline – TiO2 composite thin films fabricated using dip coating technique with minimum film thickness could be a feasible solution in controlling the corrosion in oil pipelines with good film stability, high durability, with a cost effective and environmentally friendly approach.

Influence of particle size reduction in ball milled rutile TiO2 on the properties of PVDF-HFP/ TiO2 nanocomposite films as dielectric layers for electro adhesive load bearing applications

Influence of particle size reduction in ball milled rutile TiO2 on the properties of PVDF-HFP/ TiO2 nanocomposite films as dielectric layers for electro adhesive load bearing applications

Self-powered broadband photodetection with mixed-phase black TiO2-assisted output boosting of a biobased triboelectric nanogenerator

Simultaneously harvesting vibrating energy and solar energy from the ambient environment through triboelectric nanogenerators (TENGs) to construct a self-powered system is fascinating and exacting work. In this study, photoinduced biobased triboelectric generation during friction between a PDMS@black TiO2 nanocomposite film and a chemically treated human hair film was demonstrated. The triboelectric output voltage and current signals were intensified by approximately 1.2–2.2 times, with output maxima of 85 V and 3.5 µA after illumination under full-spectrum conditions. Upon illumination, the output signals of the TENGs were appreciably altered depending on the intensity and wavelength of the light, delivering superior photoresponse characteristics, which included an outstanding responsivity of 606.8 V W−1 and an ultrabroad detection range that extended over the ultraviolet (UV), visible and near-infrared (IR) regions, thereby providing a novel route for energy harvesting devices. These devices, along with self-powered photodetectors, ameliorate other environmental issues by eliminating human hair waste and developing a closed-loop system that promotes the responsible use of resources.

Enhancement of opto-electrical properties in Co doped CdS–TiO2 nanocomposite thin film as photoanode for Semiconductor Sensitized Solar Cells (SSSCs)

Cobalt doped CdS–TiO 2 nanocomposite thin films were coated on glass substrates by bottom up approaching methods. ZnS nanolayer over cobalt doped CdS–TiO 2 films act as a protective layer of CdS nanocrystal which enhances the photo stability. The structural, optical, electrical and surface morphological properties of ZnS-cobalt CdS–TiO 2 composite thin film were systematically evaluated. Structural analysis indicates that Co 2+ ions have been successfully incorporated in CdS site. The doping of cobalt in ZnS–CdS–TiO 2 film gives rise to an increase in the lattice parameter while the band gap decreased with increasing cobalt concentration. The bandgap of doped film decreases indicating the easy way of electron transfer from valence band to conduction band of CdS and TiO 2 . Surface morphological studies shows the diffusion of cobalt doped CdS nanoparticles into TiO 2 nanoporous structure of the composite film . The emission peaks in photoluminescence spectrum of ZnS-cobalt CdS–TiO 2 film proved the clear interaction of cobalt dopant with CdS nanocrystals. An enhancement in conductivity was observed due to incorporation of cobalt in CdS site and the resistance value (∼47%) was significantly decreased for cobalt doped CdS under illumination condition. Electrical analysis proved that the doped film is preferred as conductive electrode in solar cells than undoped film. • Cobalt doped CdS–TiO 2 composite thin films were synthesized by simple wet chemical method. • Interlocked CdS nanocrystals observed in SEM analysis, facilitate easy penetration into TiO 2 nanoporous structure of the composite film. • The doped film exhibit shifting of absorption edge towards longer wavelength (red shift), indicates decreased optical band gap. • The doped film shows superior electrical performance due to decreased resistance, preferred as conductive electrode in solar cells.

Deep understanding in physical and electrochemical performance of WO3–TiO2 nanocomposite thin films deposited onto ITO and FTO coated glass substrates using a thermionic vacuum arc deposition system

In this work, WO3–TiO2 nanocomposite thin films were deposited via thermonic vacuum arc technique and the physical and electrochemical features of these nanocomposites were investigated. The average transmittance values were obtained 66.9% and 58.7%, particularly the mean absorbance values were 0.49 and 0.59 onto ITO and FTOcoated glass substrate. The optical band gap of the layers were calculated 2.59 and 2.62 eV upon ITO and FTO coated glass substrates, respectively. Measurement outputs show that both coated thin films are conductive and good storage capabilities for Li+ ions. The reversibility of the films is calculated at 7% and 15% on ITO coated glass and FTO coated glass substrates, respectively. Considering that WO3 and TiO2 materials separately show high quality electrochromic properties, it is aimed to produce these two materials as composites and to examine their electrochromic properties using different producing techniques.

Influence of nanofiller concentration on polypropylene nanocomposites for high voltage cables

Abstract Polymeric insulation for HVDC cable is attracting more attention in the modern power transmission system. Especially, the thermoplastic material is desirable for power cable insulation because of its recyclability and ease of processing. Thermoplastic material development is a good alternative to cross-linked polyethylene in the future. Polypropylene has the advantage of avoiding by-products during cable production, which can minimize space accumulation and degassing costs. Therefore, this study investigates the influence of nanofillers on the structural properties of isotactic polypropylene. In addition, the proposed composite material’s morphology, melting, dielectric permittivity, and breakdown strength are examined. Different weight percentages of inorganic nanofillers such as TiO2 and ZnO are used to make nanocomposite thin films. With increasing filler concentration, the dielectric constant of the nanocomposite thin film increases. Apart from that, the dielectric loss of the TiO2 nanocomposite thin film increases with weight percentage initially and it falls nearer to virgin material at a higher frequency. The breakdown strength of the nanocomposite materials shows a similar variation with filler concentration. TiO2 is more resistant to deterioration than ZnO composite. Based on the results of the complete investigation, the TiO2 nanocomposite is better suited for the insulation of HVDC cables.

Substrate effect on electrochromic properties of Nb2O5:TiO2 nanocomposite thin films deposited by thermionic vacuum arc

In this paper, substrate effect on electrochromic properties of Nb2O5:TiO2 nanocomposite thin films have been investigated. Thin films have been deposited by thermionic vacuum arc deposition technology. Nb2O5 and TiO2 are known to be electrochromic materials. Nb/Ti rate was obtained 1.4. Average thicknesses of the films were found as 113 nm and 111 nm and band gap values for bleached states were calculated as 3.96 eV and 3.85 eV for the films deposited onto ITO and FTO coated glass substrates, respectively. The coloration efficiency values were calculated as 17 cm2/C and 26 cm2/C for the film onto ITO layered glass substrate and 31 cm2/C, 23 cm2/C and 24 cm2/C for the film onto FTO layered glass substrate at a different wavelength values in the visible region. The obtained results shows that films for each transparent conductive oxide material is promising material to obtain the high performance TiO2 active layer.

Spatially selective nanoplasmonic response in Ag embedded GLAD TiO2 nanocomposite thin films

The nanoplasmonic behaviour of Ag decorated TiO2 film structure was spatially varied across the sample surface by utilizing the tailored optical response of the underlying dielectric TiO2 thin film prepared using a novel collimated glancing angle deposition technique (collimated-GLAD). A blue shift in maximum attenuation coefficient region and minimum film transmittance region of the Ag/collimated-GLAD TiO2 nanocomposite coating with increase in height from the evaporation source was detected. The presence of minimum transmittance region was found to have occurred due to localized surface plasmon resonance (LSPR) phenomenon with additional contribution from thin film interference. The measured transmittance spectra showed spatial selectivity in LSPR wavelength of ∼22 nm with increase in height from the evaporation source. The variation of surrounding medium's (i.e. the TiO2 layer) refractive index (with height from the evaporation source) of the Ag nanostructures was the key factor responsible for the spatially varying nanoplasmonic response of Ag/collimated-GLAD TiO2 film across the sample surface. The Surface enhanced Raman scattering (SERS) characterization of the Ag/collimated-GLAD TiO2 film revealed photocatalysis driven dimerization conversion of p-aminothiophenol (p-ATP) molecules to p,p’-dimercaptoazobisbenzene (DMAB) due to the localized surface plasmons of the film structure along with the substantial enhancement in the Raman peak intensities compared to the blank substrate.

Fabrication of CdSe/ZnIn2S4 modified TiO2 nanotube composite and its application in photoelectrochemical cathodic protection

In order to obtain a TiO2 nanocomposite film with enhanced photoelectrochemical properties for corrosion protection of metals, a TiO2 nanotube film was fabricated on a Ti substrate via anodization, then ZnIn2S4 nanosheets and CdSe nanoparticles were sequentially deposited on the TiO2 film by hydrothermal treatment and electrodeposition, respectively. The CdSe/ZnIn2S4 co-modified TiO2 heterostructured nanocomposite film showed remarkably enhanced visible light absorption and photoelectrochemical properties. Under white light irradiation, the photocurrent density of the nanocomposite film in the mixed solution with 0.1 M Na2S and 0.1 M Na2SO3 was 33 times higher than that of the TiO2 film. The nanocomposite could negatively shift the potential of the coupled 403 stainless steel immersed in a 0.5 M NaCl solution by 440 mV, showing efficient photoelectrochemical cathodic protection.

Effect of Heating Rate on the Photocatalytic Activity of Ag–TiO2 Nanocomposites by One-Step Process via Aerosol Routes

Ag–TiO2 nanocomposite films, based of Ag and TiO2 nanoparticles, were fabricated in a one-step aerosol route employing the simultaneous plasma-enhanced chemical vapor deposition and physical vapor deposition systems. The as-fabricated films were subjected to different heating rates (3 to 60 °C/min) with a constant annealing temperature of 600 °C to observe the significant changes in the properties (e.g., nanoparticle size, crystalline size, crystallite phase, surface area) toward the photocatalytic performance. The photocatalytic activity was evaluated by the measurement of the degradation of a methylene blue aqueous solution under UV light irradiation, and the results revealed that it gradually increased with the increase in the heating rate, caused by the increased Brunauer–Emmett–Teller (BET) specific surface area and total pore volume.

Pyroelectric Nanogenerator Based on an SbSI-TiO2 Nanocomposite.

For the first time, a composite of ferroelectric antimony sulfoiodide (SbSI) nanowires and non-ferroelectric titanium dioxide (TiO2) nanoparticles was applied as a pyroelectric nanogenerator. SbSI nanowires were fabricated under ultrasonic treatment. Sonochemical synthesis was performed in the presence of TiO2 nanoparticles. The mean lateral dimension da = 68(2) nm and the length La = 2.52(7) µm of the SbSI nanowires were determined. TiO2 nanoparticles served as binders in the synthesized nanocomposite, which allowed for the preparation of dense films via the simple drop-casting method. The SbSI–TiO2 nanocomposite film was sandwiched between gold and indium tin oxide (ITO) electrodes. The Curie temperature of TC = 294(2) K was evaluated and confirmed to be consistent with the data reported in the literature for ferroelectric SbSI. The SbSI–TiO2 device was subjected to periodic thermal fluctuations. The measured pyroelectric signals were highly correlated with the temperature change waveforms. The magnitude of the pyroelectric current was found to be a linear function of the temperature change rate. The high value of the pyroelectric coefficient p = 264(7) nC/(cm2·K) was determined for the SbSI–TiO2 nanocomposite. When the rate of temperature change was equal dT/dt = 62.5 mK/s, the maximum and average surface power densities of the SbSI–TiO2 nanogenerator reached 8.39(2) and 2.57(2) µW/m2, respectively.

Optical characterizations of PMMA/metal oxide nanoparticles thin films: bandgap engineering using a novel derived model

We synthesize and optically characterize pure PMMA and PMMA incorporated with metal oxides nanoparticles (MO NPs) such as ZnO, CuO, TiO2 and SiO2 NPs nanocomposite thin films with weight concentration of 10% using dip-coating technique. SEM images of MO NPs show that all NPs have nearly an average size of around 50 nm. The optical parameters such as, optical parameters (n and k), optoelectronics properties, dispersion, band-gap energy and band structure of as-prepared nanocomposite thin films were determined by analyzing the transmittance and reflectance spectra. Mainly, optical band-gap energy (Eg) and the thickness of thin films are evaluated to a high degree of accuracy by utilizing Q-functional derived using a mathematical model recently published. The Q(E) is a functional containing experimental transmission and reflection data and the incident photon energy. The Eg value of un-doped PMMA thin films is found to be 4.273 eV. This value decreases as pre-selected MO NPs are introduced into thin films. These values are in excellent agreement with those determined using Tauc method. The FTIR technique is employed to elucidate the vibrational bands of the nanocomposites and the intermolecular bonding between PMMA matrix and the MOs NPs. Thermal stability is investigated by employing thermogravimetric analysis (TGA) at temperatures up to 400 °C. The obtained TGA thermograms indicate that adding MOs NPs to PMMA yield thin films of better thermal stability. The obtained doped thin films show a great promise for fabricating high-efficient optoelectronic devices.

Sun light driven photocatalytic performance of Ag decorated TiO2 nanocomposite thin films by sol gel method

High performance, low cost photocatalysts are essential for water treatment applications. However the existing majority of the photocatalysts limited to Ultra violet and visible region only. Besides the fabrication of photocatalysts, there is a huge demand for low cost, recyclable and solar light trapping photocatalysts, thereby effectively remove the organic pollutants present in water. Here, we have synthesized the solar light active Ag loaded TiO2 nanocomposite thin films by sol gel method. X ray diffraction, scanning electron microscopy and UV–visible spectroscopy were applied to characterizing the product. The results show that we successfully synthesized the silver doped titanium dioxide thin films. The silver doped titanium dioxide thin films show red shift and broad absorption band in the whole UV visible region in comparison with bare titanium dioxide. The results show that the Ag-TiO2 nanocomposite exhibit best photocatalytic efficiency under direct sun-light irradiation due to increased electron transfer and charge separation. The photodegradation activities of the Ag doped TiO2 were studied with model organic pollutants. Ag doped TiO2 sample showed 98% degradation efficiency in just 70 min under sun light irradiation. Repeated cycle runs revealed that these catalysts exhibit reusability and excellent stability, able to trap solar light efficiently and suitable for degradation of many organic pollutants. The performances of the Ag-TiO2 nanocomposites indicate that, these catalysts can find potential applications in photocatalytic water treatment plants.

Physical and structural properties of whey protein concentrate - Corn oil - TiO2 nanocomposite films for edible food-packaging

Interest in polymer technology based on biodegradable and edible films has increased dramatically, in hopes of creating a circular economy with little to no environmental impact. In this study nanocomposite films with a glycerol/WPC ratio of 4/5 were prepared from emulsions containing 2.5, 5.0, or 7.5 wt.% WPC and 2 wt.% corn oil. Films also contained a load of 0.5 wt.% TiO2. Emulsions were prepared with two different droplet sizes: conventional (from 300 to 700 nm) and nano (from 60 to 80 nm). Films were analyzed for color, water vapor permeability, thermogravimetric, mechanical/tensile properties, infrared behavior, and structure. Advanced X-ray microscopy based on small and wide-angle scattering contrast was used to investigate the nanocomponents in the films, allowing the identification of the main scattering species. Film that was prepared from starting systems with nano droplets (60 nm), the highest protein concentration (7.5 wt.% WPC), and TiO2 loading had the greatest E’ (elastic modulus, 19.2 MPa), E (Young modulus, 19.4 MPa), and εb (elongation at break, 119 %) values. This nano-based film had suitable physical properties for cheese packaging and other similar applications. In all films, data showed a close correlation between film structure and mechanical/tensile properties.

Substrate temperature dependence of chemical state and magnetoresistance characteristics of Co–TiO2 nanocomposite films

Abstract Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures. The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and superparamagnetic properties. When the substrate temperature increases from room temperature to 400 °C, Co particles gradually grow, and the degree of Co oxidation significantly decreases. Consequently, the saturation magnetization increases from 0.13 to 0.43 T at the same Co content by increasing the substrate temperature from room temperature to 400 °C. At a high substrate temperature, conductive pathways form among some of the clustered Co particles. Thus, resistivity rapidly declines from 1600 to 76 μΩ·m. The magnetoresistive characteristic of Co−TiO2 films is achieved even at resistivity of as low as 76 μΩ·m. These results reveal that the obtained nanocomposite films have low Co oxidation, high magnetization and magnetoresistance at room temperature.

Phase transformation of poly (vinylidene fluoride)/TiO2 nanocomposite film prepared by microwave-assisted solvent evaporation: An experimental and molecular dynamics study

Poly (vinylidene fluoride) (PVDF), which is a representative piezoelectric polymer, has received immense attention from various industries owing to its high flexibility, durability, and low cost. In this study, the phase transformation mechanism of TiO2 nanoparticle-reinforced PVDF composite films during microwave-assisted solvent evaporation was investigated by experimental and numerical analysis. The crystalline behaviors of the prepared PVDF/TiO2 nanocomposite films were investigated using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The degree of crystallinity of the films was calculated from the XRD results using a curve deconvolution method. In order to understand the mechanism behind the experimental results, numerical simulations based on molecular dynamics (MD) were performed. The effect of microwave irradiation on the PVDF crystalline behavior was discussed by observing the change in the dihedral angle conformation of the amorphous PVDF simulation model. In addition, molecular-level insights on the interaction of PVDF with TiO2 nanoparticle were provided using the concepts of dipole moment change and dihedral angle conformation change in order to analyze the effect of TiO2 on the crystal conformation of the PVDF. Furthermore, the change in the dihedral angle conformation of PVDF chains reinforced with TiO2 nanoparticles under microwave irradiation was observed.

Synthesis and evaluation of highly dispersible and efficient photocatalytic TiO2/poly lactic acid nanocomposite films via sol-gel and casting processes

Using titanium teraisopropoxide (TTIP) as the hydrolysis material, titanium dioxide (TiO2) (6.3–11.1 nm) nanoparticles were synthesized via the sol-gel method and reinforced into poly lactic acid (PLA)/TiO2 nanocomposite films by casting. The effect of increasing amounts of TiO2 on the structure and properties of PLA/TiO2 nanocomposite films were evaluated. These results indicated that self-aggregation of TiO2 nanoparticles in PLA films could be avoided via sol-gel and casting processes. The presence of TiO2 significantly improved the tensile strength and thermal stability of films. The PLA/TiO2 (0.6 wt%) film exhibited the highest photocatalytic activity efficiency under UV irradiation and displayed high antibacterial activities with optimal inhibition zones of Staphylococcus aureus, followed by Escherichia dispersibility of TiO2 in films were responsible for those improvements. This study suggests that PLA/TiO2 nanocomposite films could be a promising antimicrobial alternative material to conventional plastic packages.