Titanium Butoxide Research Articles

Controlled preparation of lignin/titanium dioxide hybrid composite particles with excellent UV aging resistance and its high value application

In this work, a novel lignin/titanium dioxide (QAL/TiO2) hybrid composite with regular microstructure and synergistically enhanced UV absorption properties was synthesized by a simple hydrothermal method using lignin and butyl titanate. The prepared QAL/TiO2 composite is hybrid structure in which lignin and TiO2 is uniformly embedded, and has strong chemical bond bonding force. The QAL/TiO2 hybrid composite particles were used for doping modification of waterborne polyurethane (WPU), which had good interfacial compatibility and dispersibility in WPU. The obtained WPU + QAL/TiO2 film shows excellent UV shielding performance and great mechanical properties, the tensile strength and elongation at break are significantly improved compared with pure WPU film. And it also has excellent anti-UV aging property, that the mechanical performance basically remains unchanged after 96 h of high power ultraviolet irradiation. This work not only provides a kind of lignin/TiO2 hybrid composite with neat structure, good dispersion and excellent optical properties, but also has great significance for the high-valued utilization of biomass resources.

Flame-retardant and water-repellent coating on cotton fabric by titania–boron sol–gel method

This work aims to prepare a series of sols based on Titanium (IV) butoxide (TBT) and using boric acid as a functional additive. The sols were applied onto the cotton fabric by the pad-pry-cure process. The as-obtained cotton fabrics were characterized using Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analysis in order to determine their chemical composition and their surface morphology, respectively. The results indicate the formation of TiO2–boron-based coating over the surface of coated cotton fabric. X-ray diffraction (XRD) patterns showed that the coating did not affect the crystallographic structure of the cellulosic fabric. The functional properties of the treated samples were measured from thermo-oxidative stability and burning behavior performance, drop absorption and water uptake measurements. The results showed that the coated cotton fabrics by the sol–gel approach through the application of TiO2–boron-based coating with 2.5 molar ratio of boric acid possessed high thermal stability and flame retardancy. Most importantly, a total burning time of 2 s and a residue of more than 90% were obtained after 10 s of flame application, indicating that the functionalized cotton fabric self-extinguished the fire rapidly. The water-repellent properties were also enhanced and the obtained results mentioned that the drop time and the water uptake were improved compared with untreated cotton fabric. The effect of the application of TiO2–boron-based coatings on the mechanical properties of cotton samples, as well as their washing fastness were studied.

Insight into enhanced visible light photocatalytic activity of Fe3O4–SiO2–TiO2 core-multishell nanoparticles on the elimination of Escherichia coli

A nano photocatalyst of Fe3O4–SiO2–TiO2 (FST) was produced, which can be used as a magnetic adsorbent in water treatment e.g. elimination of E.coli. Synthesis of shells on the initial Fe3O4 nanocores was carried out via the sol-gel technique. VSM, PSA, XRD, TEM, FE-SEM, EDS, FTIR and ZETA were analyses conducted for characterization. A 10-nm-passive layer of silica was formed between magnetic core and titania shell to inhibit direct contact of core and shell while superparamagnetic property was preserved. For TiO2 synthesis, it was found that the “concentration of water” and “mixing order of water and TBOT (Titanium butoxide)” had significant effect. Moreover, a minimum ratio of water to TBOT was required for TiO2 nucleation on Fe3O4–SiO2 (FS) seeds. Furthermore, an increment of water concentration to 3.8 M has led to 95% TiO2 coverage on FS nanoparticles. Results showed that FST nanoparticles were completely stable at pH = 7 and had acceptable zeta potential approximately −65 mV. Also, TiO2-coated magnetite nanoparticles (FT) were synthesized with the same condition of FST, but without silica midlayer, in order to observe th effect of SiO2 in nanostructure. Treatment of FST nanoparticles with E.coli showed 98% bacteria adsorption after 100 min, as well significant damage to bacteria cell membrane, was observed by SEM images. However, FT nanoparticles represented 82% bacteria removal with no harsh damage to the cells. This work demonstrated effective presence of SiO2 as a passive layer between Fe3O4 and TiO2 for photocatalytic efficiency improvement.

Fabrication of titanosilicate pillared MFI zeolites with tailored catalytic activity

Titanosilicate pillared MFI zeolite nanosheets were successfully synthesized by infiltrating the mixed tetraethyl orthosilicate (TEOS)/tetrabutyl orthotitanate (TBOT) solvent into the gallery space between adjacent MFI zeolite layers. The obtained zeolite catalysts were characterized using powder X-ray diffraction, N2 adsorption/desorption isotherms, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy techniques. The H2O2 oxidation of dibenzothiophene (DBT) was used to evaluate the catalytic performance of the obtained titanosilicate pillared MFI zeolites. The conversion of DBT and selectivity of dibenzothiophene sulfone (DBTS) were most affected by the textural properties of the zeolites. This was attributed to the DBT and DBTS molecules being larger than micropores of the MFI zeolites. The conversion of DBT and yield of DBTS could be systematically tailored by tuning the molar ratio of the TEOS/TBOT solvent. These results implied that a balance between the meso- and microporosity of zeolites and tetrahedrally coordinated Ti (IV) active sites of titanosilicate pillars can be achieved for the preparation of desired catalysts during the oxidation of bulk S compounds.

Hydrothermally grown novel pyramids of the CaTiO3 perovskite as an efficient electrode modifier for sensing applications

Herein, we report novel CaTiO3 pyramids, prepared by a hydrothermal approach using calcium nitrate and titanium butoxide in the presence of sodium hydroxide.

Synthesis and Characterization of Highly Porous TiO2 Scaffolds for Bone Defects

The purpose of this study was to fabricate and investigate the highly porous structure using titanium dioxide, which is a candidate for bone defect repairing. For this purpose, TiO2 scaffolds were synthesized using titanium butoxide, Pluronic F127 surfactant, and polyurethane foam blocks. Therefore, a colloid includes titanium butoxide and F127 and the polyurethane foams were immersed in it. The samples were annealed at different temperatures in the range of 500 to 600 ° C. The results of simultaneous thermal analysis (STA) test showed that volatile materials left the system completely when the temperature reached 550 oC. Also small angle X-ray scattering (SAXS) test revealed that these scaffolds composed of highly ordered mesoporous structures. The obtained scaffolds at 550 oC had specific surface area of 85.736 m2g-1with the mean mesopore size of 7.0498 nm and macroporosity in the range of 100 to 350 μm. The presence of mesopores and their distribution were investigated with transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The base scaffold was then immersed in a simulated body solution for 3,7and 14 days and analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray. The results show its ability for apatite formation.

Synthesis and study of TiO2/CuO core shell nanoparticles for photovoltaic applications

Metal oxide nanomaterials have a great importance in the science and industrial world today. Titanium dioxide (TiO2) is a well-known oxide material and used in photovoltaic devices due to its high porosity, high stability and stable energy band gap. TiO2 can be doped with different materials such as gold and silver to enhance its structural and optical properties. In this work, we report the synthesis of TiO2/CuO core shell by sol-gel technique using titanium butoxide, zinc nitrate and copper nitrate as precursors. TiO2 is doped with CuO due to its good absorption efficiency and electrical properties. Moreover Fermi level of copper is 4.65 eV which is between gold (5.1 eV) and silver (4.26 eV) making copper suitable and cheap candidate to replace noble metals. Its atomic radius is approximately same as that of TiO2. The structure and optical properties of prepared samples are characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) and Ultraviolet/visible (UV–Vis) techniques. XRD data indicates an increase in the crystalline size from 4 to 7 nm on increasing the concentration of copper from 0.5 to 1.5 at% in sample 1–3 (TiO2: Cu (0.5–1.5 at%)). XRD and FTIR analysis confirms that Cu existed in TiO2 nanoparticles in the form of CuO. TEM images have shown that the nanoparticles of TiO2: Cu exists in spherical shape and exhibit core–shell structure. UV–Visible results reveal the decrease in TiO2 band gap energy with increase in doping concentration of Cu in TiO2. UV–Visible results also show high absorption in Cu-doped TiO2 as compared toundoped TiO2.

Photocatalytic Properties of Thermally Annealed Films of Titanium Butoxide-=SUP=-*-=/SUP=-

We show that titanium dioxide particles capable of Reactive oxygen species generation can be produced in titanium butoxide films by annealing them at 500oC. Optimal conditions for the films deposition by a modified Langmuir-Blodgett technique were selected basing on the film uniformity examined by optical and electron microscopy. The photocatalytic activity of the annealed film was tested using RNO sensor bleaching.

Exceptional photocatalytic activity for Ag,Cr- SrTiO3 activated by H2O2 for removal of organic pollutants

Ag,Cr-SrTiO3 nanocomposite was successfully prepared through the one-pot situ solvothermal method by using butyl titanate, CrCl3·6H2O and Sr(NO3)2 as raw materials. The obtained nanocomposites were characterized by x-ray diffraction, scanning electron microscopy and x-ray photoelectron spectroscopy. UV-visible diffuse reflectance spectroscopy was used to investigate the optical properties and the results demonstrated the extension of spectral response from ultraviolet to visible light region. Compared with pure SrTiO3, Ag,Cr-SrTiO3 exhibited remarkable enhancement in adsorption and photocatalytic ability. More importantly, samples activated by H2O2 revealed extraordinary photocatalytic activity, which could remove 98.8% of MO within 60 min with 0.4 wt% Ag,Cr-SrTiO3. This work not only indicates that Ag,Cr-SrTiO3 is a desired photocatalytic material to degrade of organic pollutants under enlarging response range of solar light, but also shows that the addition of H2O2 can promote the photodegradation reaction.

Preparation and Photocatalytic Property of Ag Modified Titanium Dioxide Exposed High Energy Crystal Plane (001)

TiO2 exposed high energy crystal plane (001) was prepared by the sol-gel process using butyl titanate as the titanium source and hydrofluoric acid as the surface control agent. Ag-TiO2 was prepared by depositing Ag on the crystal plane of TiO2 (101) with a metal halide lamp. The surface morphology, interplanar spacing, crystal phase composition, ultraviolet absorption band, element composition, and valence state of the samples were characterized by using field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD), ultraviolet-visible absorption spectrum (UV-Vis-Abs), and X-ray photoelectron spectroscopy (XPS), respectively. The formation mechanism of high energy crystal plane (001) was discussed, and the photocatalytic activities were evaluated by following degradation of methyl orange. The results show that TiO2 exposed the (001) crystal plane with a ratio of 41.8%, and Ag can be uniformly deposited on the crystal plane of TiO2 (101) by means of metal halide lamp deposition. Under the same conditions, the degradation rate of methyl orange by deposited Ag-TiO2 reaches as much as 93.63% after 60 min using the metal halide lamp (300 W) as an illuminant, 81.89% by non-deposited samples and 75.20% by nano-TiO2, causing a certain blue shift in the light absorption band edge of TiO2. Ag-TiO2 has the best photocatalytic performance at a pH value of 2.

Comparison of the structural and photo-catalytic properties of nanostructured Fe3O4/TiO2 core-shell composites synthesized by ultrasonic and Stöber methods

In the present research, Fe3O4/TiO2 magnetic photo-catalytic nanocomposites with a core/shell structure were successfully synthesized using two techniques of ultrasonic and St?ber. In this way, iron oxide (II, III) nanoparticles as soft magnetic cores of this composite were prepared by utilizing a chemical method assisted by ultrasound with a Fe+3/Fe+2 molar ratio of 1.5 under the nitrogen atmosphere. Thereafter, titanium oxide coating was performed on Fe3O4 nanoparticles by using tetrabutyl orthotitanate (TBOT) and titanium isopropoxide (TTIP) precursors. The resultant nanostructures were characterized by means of X-ray powder diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, energy dispersive X-ray (EDX) analysis, vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Through findings obtained from TEM examinations, the formation of core/shell nanostructure was confirmed in the prepared Fe3O4/TiO2 composites. Analysis of magnetic properties revealed that titanium oxide coating on iron oxide nanoparticles reduces saturation magnetization (Ms). The values of saturation magnetization for Fe3O4 powder and Fe3O4/TiO2 nanocomposite powders achieved via ultrasonic and St?ber methods were 60, 23 and 9 emu/g, respectively. Photo-catalytic properties of Fe3O4/TiO2 nanostructures were evaluated by the use of methylene blue dye under UV light. Results indicated that Fe3O4/TiO2 composite obtained by the St?ber method has a better photo-catalytic property as well as a decreased but acceptable magnetic separation. Degradation of methylene blue dye in the presence of photo-catalytic powder prepared by ultrasonic and St?ber procedures was 61 and 69 %, respectively, within 90 minutes of UV light exposure.

Characterization and evaluation of primer formulations for bonding silicone rubber to metal

The aim of this study was to explore the chemistry and adhesive properties of industrial primer formulations used for bonding silicone elastomers on AA6061 aluminum alloy. The composition of different primer formulations was determined using conventional chemical analyses. Adhesion strength was measured using 90° peel test. The formulation comprising partially condensed vinyltrimethoxysilane (VTMS) and tetrapropoxysilane (TPOS) and titanium tetrabutoxide (TTB) catalyst showed a strong adhesion to metal but a low adhesive strength of the primer-elastomer interface. 29Si NMR spectroscopy results have shown that exchange reactions of alkoxy groups of VTMS, TPOS and TTB has occurred in the formulation. Surprisingly, one formulation was free of silane and consisted of a one-component addition curing system comprising a SiH oligosiloxane, a vinyl-PDMS with a Pt catalyst and silica filler. This formulation enabled high cohesive strength of the primer and primer-elastomer interphase but it showed low adhesion to the metal. The more complex formulation containing a mixture of silanes (vinyltriethoxysilane, methyltriethoxysilane and tetraethoxysilane), a vinyl silicone gum, a hydroxy-terminated PDMS and silica filler resulted in the highest adhesive strength with 100 % cohesive failure in the elastomer. We found that the reinforcement effect of silica filler plays an important role in the promotion of adhesion.

Plasmonic hybrid platinum-titania nanocomposites as highly active photocatalysts: self-cleaning of cotton fiber under solar light

In the present paper, a one-step, simple, efficient and low-cost strategy was demonstrated for preparing of highly stable hybrid platinum-titania (Pt@TiO2) photocatalyst by solvothermal wet chemical process. Platinum (Pt) in the metallic form combined with titania (TiO2) in the crystallographic anatase form has been manufactured using Dimethyl Sulfoxide (DMSO) as a solvent and surfactant using titanium (IV) butoxide and hydrogen hexachloroplatinate(IV) precursors. Full characterization of the hybrid nanomaterials including their morphology, crystalline structure and optical properties was determinate using different experimental techniques such as XRD, TEM and UV–vis spectroscopy. TEM images showed spherically shaped Pt nanoparticles (NPs) of the diameter 5–10nm with good particle size distribution. The EDXRF data revealed that Pt NPs are in metallic form. Optical investigation show that Pt@TiO2 NPs exhibits a good optical response under UV–vis light excitation compared to bare-TiO2. Furthermore, photocatalytic investigation of Pt@TiO2 colloids photocatalyst towards the photodegradation of diuron, as a model organic pesticide was reported. The hybrid Pt@TiO2 photocatalyst prove high-performance on the photodecomposition of the pesticide under solar light within only 60 min. In the other hand, the plasmonic hybrid Pt@TiO2 was incorporated into the cotton fabric to attain a modified fiber with high self-cleaning activity.

Optimizing the synthesis of SnO2/TiO2/RGO nanocomposites with excellent visible light photocatalytic and antibacterial activities.

Multifunctional SnO2/TiO2/RGO nanocomposites with enhanced photocatalytic degradation and antibacterial activity have been successfully synthesized by a facile one-pot environmentally friendly green hydrothermal route using titanium tetrabutoxide (TBOT), Na2SnO3 and graphene oxide (GO) without reducing agents and any structure-directing agents. The results demonstrate that the reaction pH conditions play important roles in the control of the crystallographic phases of TiO2 and SnO2. In addition, the visible-light-active photocatalytic and antibacterial activities of the synthesized composites were measured for the degradation of rhodamine B (RhB) and the growth inhibition of the Gram-negative bacteria Escherichia coli (E. coli), which are strongly affected by the SnO2 loading content, the crystal structure of TiO2 and the appropriate addition of graphene. The superior photocatalytic and antibacterial activities of the nanocomposites were attributed to their great optical adsorption capability and excellent charge separation and transfer efficiency. This study may provide new insights into the fabrication of efficient visible-light-active SnO2/TiO2/RGO nanocomposites and expand their applications in the environmental remediation and water disinfection fields.

Green synthesis of TiO2 nanoparticles using Bixa orellana seed extract and its application for solar cells

Mesoporous anatase TiO2 nanoparticles are the best photoanode materials for high performance DSSC. Chemical and physical methods used for the preparation of TiO2 nanoparticles suffer with environment related issues e.g. use of toxic solvents, hazardous by-products and consumptions of high energy. We have synthesized mesoporous anatase TiO2 nanoparticles from Titanium (IV) butoxide solution using Bixa orellana seed extract and further used it for making DSSC photoanode. The method offers environment friendly, cheaper and efficient DSSC. Structure, morphology, size and porosity of TiO2 nanoparticles were characterized using XRD, SEM, TEM and N2 sorption measurements. The amount of dye loading by TiO2 was obtained using desorption technique which revealed much higher dye loading for the plant seed grown nanoparticles (G-TNP). TNP and G-TNP demonstrated photovoltaic conversion efficiencies 1.03% and 2.97% respectively. This study therefore demonstrates that the synthesized mesoporous anatase TiO2 naoparticles can serve as promising photoanode materials for DSSC applications.

Synthesis and characterization of Zn-incorporated TiO2 thin films: impact of crystallite size on X-ray line broadening and bandgap tuning

In the present work, the synthesis of pure and Zn-doped TiO2 thin films is reported using a simple and cost-effective thermal spray pyrolysis technique (SPT) with an aim to investigate the influence of Zn doping on the structural, morphological, optical and the electrical properties of TiO2 nanoparticles. The resulted TiO2 thin films have been deposited on commercial glass slides at substrate temperature of 450 °C using titanium(IV) butoxide as a precursor. The samples are structurally characterized by X-ray diffraction (XRD) method. Surface morphology, optical and electrical properties of the sample are elucidated by field emission scanning electron microscopy (FESEM), UV–visible spectroscopy and four-point probe method, respectively. X-ray diffractograms show the formation of pure anatase TiO2 phase and after Zn doping anatase phase of TiO2 remains unaltered. The crystallite size is found using the Scherrer method and also Williamson–Hall (W–H), Halder–Wagner (H–W) and Wagner–Agua (W–A) methods are employed to estimate the crystallite sizes and the strain from X-ray peak-broadening analysis. The obtained results indicate that the crystallite size and the lattice strain evaluated from Scherrer method, W–H, H–W and W–A analyses are highly intercorrelated. The characterization results of FESEM illustrate the existence of homogenous and well-dispersed spherical grains with the average diameter of 22–8 nm and agglomerated grains are observed as the Zn is inserted into TiO2 lattice as dopant. The estimated value of optical bandgap of TiO2 nanoparticles is red shifted from 3.86 to 3.78 eV and 4.12 to 4.04 eV in Tauc relation and K–M function, respectively. From four-point probe setup, it is found that the pure film deposited at 450 °C has manifested lowest resistivity 4.25 × 10−3 Ω-cm and then decreased further with increase of Zn contents.

Synthesis of TiO₂-Reduced Graphene Oxide Nanocomposites Offering Highly Enhanced Photocatalytic Activity.

Photogenerated electron-hole recombination significantly restricts the catalytic efficiency of titanium dioxide (TiO₂). Various approaches have been developed to overcome this problem, yet it remains challenging. Recently, graphene modification of TiO₂ has been considered as an effective alternative to prevent electron-hole recombination and consequently enhance the photocatalytic performance of TiO₂. This study reports an efficient but simple hydrothermal method utilizing titanium (IV) butoxide (TBT) and graphene oxide (GO) to prepare TiO₂-reduced graphene oxide (RGO) nanocomposites under mild reaction conditions. This method possesses several advantageous features, including no requirement of high temperature for TiO₂ crystallization and a one-step hydrothermal reaction for mild reduction of GO without a reducing agent, which consequently makes the production of TiO₂-RGO nanocomposites possible in a green and an efficient synthetic route. Moreover, the as-synthesized nanocomposites were characterized by numerous advanced techniques (SEM, TEM, BET, XRD, XPS, and UV-vis spectroscopy). In particular, the photocatalytic activities of the synthesized TiO₂-RGO nanocomposites were evaluated by degrading the organic molecules (methylene blue, MB), and it was found that the photocatalytic activity of TiO₂-RGO nanocomposites is ~4.5 times higher compared to that of pure TiO₂. These findings would be useful for designing reduced graphene oxide-metal oxide hybrids with desirable functionalities in various applications for energy storage devices and environmental remediation.

Characterization of the anticorrosive properties in bismuth-titanate films obtained by the sol-gel method

Sol-gel synthesis has been used since 1950 to prepare oxides. The method is attractive because the processes of obtaining the oxides are developed at room temperature; products with high purity and homogeneity are obtained, and allow the combination of several types of oxides: silicon, zirconium, titanium, aluminum, bismuth, and cerium. Sol-gel has been used to make ceramic composites with anticorrosive properties on stainless steel substrates. A class of stainless steel widely used in biomedical applications, especially in the treatment of fractures, 316L is its low economic cost relative to other materials such as titanium. Once the steel implant is inside the human body it comes into contact with body fluids that contain chloride ions. The fluid-implant interaction develops a corrosive process on the metal surface. The corrosive products of iron diffuse in the body causing tissue damage. As a possible solution to this problem, the objective of the investigation was to obtain a bismuth-titanium oxide using the sol-gel method and apply it on 316L stainless steel substrates. Bismuth nitrate pentahydrate and titanium tetrabutoxide were used as precursors. The anticorrosive response was evaluated in a simulated physiological solution, Ringer’s solution, by electrochemical impedance spectroscopy and potentiodynamic polarization curves. It is concluded that the coatings function as a corrosion barrier preventing the chloride ions Ringer’s solution reach the metal surface.

N–Si doped carbon-embedded TiO2 composite fibers: a new photocatalysts with high yields by centrifugal spinning

N–Si doped carbon-embedded TiO2 composite fibers were prepared successfully by using centrifugal spinning and subsequent heat treatment with titanium tetrabutoxide, ethyl silicate, and Polyvinyl pyrrolidone as raw materials, as well propytrimethoxysilane (KH-560) as additives. The crystalline phase, morphologies, and groups of the prepared fibers were characterized by using X-ran diffraction, scanning electron microscopy, and Fourier transform infrared, respectively. The photocatalytic properties of the composite catalyst were investigated by using RhB as the oganic dye and ultraviolet as well visible light respective as irritator. The result indicated that Si and N atoms were doped into the lattice of TiO2. The average diameter, the surface morphologies, as well the photocatalytic activity of the fibers were controlled by the composition of raw materials, especially the concentration of KH-560. The photocatalytic performance of the novel TiO2 composite fibers reached their optimal in case the concentration of aminosilane coupling agents were 2.5 wt% and 3.75 wt% under ultraviolet and visible light irradiation, respectively.

Effect of the number of layers on surface topography of bismuth-titanium coatings

The objective of this research is to perform a topographic characterization by atomic force microscopy of the surface of bismuth titanate (Bi/Ti) coatings varying the number of layers deposited on the substrates, considering that there were not results of reported studies in which these precursors were used. It is important to analyze the surface behavior of these coatings as a first phase of future researches to establish the viability of possible uses and applications in biomedical industry. The films were synthesized by the sol-gel method from bismuth nitrate pentahydrate and titanium tetrabutoxide. Subsequently, by means of the spin- coating technique, the coatings were deposited on 316L stainless steel in monolayer and bi- layer, as this type of steel has been widely used for medical applications due to its good compatibility. The roughness values of each of the coatings were also determined. It is concluded that there is a relationship between the topography of the surface and the roughness values of the films with respect to the concentration of the precursors, the number and the speed of centrifugation of the layers deposited on the substrate. High concentrations of titanium tetrabutoxide effect on the good densification characteristics of the coatings.