Morphology Of Nanotubes Research Articles

Enhanced simazine herbicide degradation by optimized fluoride concentrations in TiO2 nanotubes growth

The performance of simazine degradation using TiO2 nanotubes is strongly influenced by the morphology and structure of the nanotubes. TiO2 nanotubes were synthesized from pristine titanium foil in EG/NH4F/KOH solution using anodic oxidation technique. This study investigates the effect of fluoride concentration in the electrolytes on the efficiency of Simazine photodegradation. We found that the optimum NH4F concentration was 0.5 wt% resulted in 57.4% degradation rate of simazine after 240 min of UV illumination. The result was attributed to the well separated, ordered and uniform structure of TiO2 nanotubes. Having the optimum fluoride concentration in electrolyte is crucial as the photodegradation performance depends on the crystal structure, surface morphology, and phase stability of the TiO2 nanotubes.

Magnetic carbon nanotube as a highly stable and retrievable support for the heterogenization of sulfonic acid and its application in the synthesis of 2‐(1H‐tetrazole‐5‐yl) acrylonitrile derivatives

AbstractIn the present study, a novel magnetic carbon nanotube functionalized by chlorosulfonicacid (Fe3O4‐CNT‐SO3H) with nanotube morphology decorated by the spherical nanoparticles was prepared, characterized and introduced as a retrievable magnetic heterogeneous nanocatalyst for green synthesis a variety of 2‐(1H‐tetrazole‐5‐yl) acrylonitrile via multicomponent domino Knoevenagel condensation/ 1,3‐dipolar cycloaddition reaction between aromatic aldehydes, malononitrile, and sodium azide under solvent free conditions. The catalyst was magnetically separated from the reaction system by an outer magnetic force and recycled up to five runs without a remarkable loss in its efficiency. The as‐preparedacidic magnetic nanocomposite was characterized by different techniques inclusive Fourier transform infrared, thermogravimetric analysis, energy dispersive X‐ray, field emission scanning electron microscopy, X‐ray diffraction, vibrating sample magnetometry, CHNS elemental analysis, and acid‐base titration. Easy workup, affordability, elimination of volatile and toxic solvents, and high yield of products are some merits of this protocol.

Adsorption capacity of different types of carbon nanotubes towards metronidazole and dimetridazole antibiotics from aqueous solutions: effect of morphology and surface chemistry.

The effect of surface chemistry and morphology of carbon nanotubes (CNTs) on their adsorption capacity towards dimetridazole (DTZ) and metronidazole (MNZ) antibiotics from water solutions was investigated in this work. The CNTs studied were single-walled carbon nanotubes (SWCNTs), CNTs doped with nitrogen (N-CNTs), multiwalled CNTs (MWCNTs), and MWCNTs functionalized with carboxylic groups (MWCNT-COOH). The experimental adsorption equilibrium data were best interpreted with the Redlich-Peterson (R-P) isotherm model. At T of 25°C and pH of 7, the capacities of adsorption decreased as follows: SWCNT>MWCNT>N-CNT ≈ MWCNT-COOH, and the maximum capacities of SWCNT towards MNZ and DTZ were 101mg/g and 84mg/g, correspondingly. The SWCNT had the highest adsorption capacity because SWCNT presented the largest surface area, and was the only nanomaterial with a basic surface. The adsorption of both antibiotics on the CNTs was predominantly ascribed to the π-π stacking. The basic groups promoted the π-π stacking interactions and favored the adsorption capacity towards MNZ and DTZ. The capacity of SWCNT for adsorbing MNZ was lessening substantially by reducing the pH from 11 to 2, and the electrostatic interactions caused this trend. The Sheindorf-Rebuhn-Sheintuch adsorption model interpreted the data for the competitive adsorption of DTZ and MNZ on SWCNT adequately.

Nanoscale morphological investigation into surface coverage of platinum catalysts by ionomers on vertically aligned carbon nanotube fuel cell catalyst layers

The nanoscale morphology and configuration of carbon nanotube supports and ionomers are investigated statistically, with the aim of improving catalyst utilization for advanced vertically aligned carbon nanotube (VACNT)–based fuel cell catalyst layers. A series of three-dimensional catalyst layers of resolution 4 nm are generated by a comprehensive stochastic modeling approach known as the quasi-random nano-structural modeling method, to reflect the anisotropy and irreproducibility of the catalyst layer structures. The statistical investigation reveals that the morphology and configuration of CNTs and the consequential formation of ionomer layers on the surface of CNTs significantly affect the surface coverage by ionomers and the utilization of Pt catalysts, implying the existence of the optimal weight ratio of ionomer to carbon. The formation of ion transport paths through ionomers is likely to improve the catalyst utilization of the VACNT catalyst layers. However, excessive formation of ionomer layers leads to poor catalyst utilization by reducing the amount of gas-exposed Pt catalysts that can be conveniently accessed by reactants. Furthermore, an increment in the CNT diameter can affect the catalyst utilization directly. This may result in undesirable excessive formation of ionomer layers and consequential underutilization of Pt catalysts.

Effect of Temperature and Anodizing Potential on the Photocatalytic Activity of TiO₂ Nanotubes.

In this research, the effect of temperature and anodizing voltage on the morphology and photocatalytic activity of TiO₂ nanotubes which were fabricated in the organic electrolyte containing sodium carbonate as an additive was investigated. The FESEM results indicate that by increasing temperature, the growth rate, wall thickness of nanotubes decreased and disordered nanotube was fabricated. Besides, the photocatalytic activity of nanotubes was decreased as well. Furthermore, enhancing the anodizing voltage from 30 to 50 V leads to improvement of morphology and photocatalytic activity of TiO₂ nanotubes.

Surfactant Free Synthesis of Magnesium Oxide Nanotubes by Simple Chemical Co-Precipitation Method

A simple cost effective preparation of Magnesium oxide nanoparticles in nanotube morphology is reported using Chemical co-precipitation method. As prepared magnesium oxide nanoparticles were characterized using UV-visible spectroscopy, X-ray Diffraction, Field Emission Scanning Electron Microscope and Energy dispersive X-ray spectroscopy. As prepared magnesium oxide nanoparticles were found in nanotube morphology whose inner and outer diameter were 31 nm and 78 nm. The band gap of as prepared nanotubes were found to be 5.37eV with maximum absorbance at 200 nm.

Modeling membrane nanotube morphology: the role of heterogeneity in composition and material properties

Membrane nanotubes are dynamic structures that may connect cells over long distances. Nanotubes are typically thin cylindrical tubes, but they may occasionally have a beaded architecture along the tube. In this paper, we study the role of membrane mechanics in governing the architecture of these tubes and show that the formation of bead-like structures along the nanotubes can result from local heterogeneities in the membrane either due to protein aggregation or due to membrane composition. We present numerical results that predict how membrane properties, protein density, and local tension compete to create a phase space that governs the morphology of a nanotube. We also find that there exists a discontinuity in the energy that impedes two beads from fusing. These results suggest that the membrane-protein interaction, membrane composition, and membrane tension closely govern the tube radius, number of beads, and the bead morphology.

Surfactants and amino acids in the control of nanotubular morphology of polypyrrole and their effect on the conductivity

Polypyrrole nanotubes were prepared by the oxidation of pyrrole in aqueous solutions of methyl orange and in the presence of 1–5 wt% of surface-active additives, surfactants, or amino acids. Three types of additives – anionic, non-ionic, and cationic – have been tested in the control of polypyrrole morphology and conductivity. The morphology of nanotubes was little dependent on surfactant type but the changes in size and aspect ratios were more pronounced with amino acids. Except for anionic surfactant, bis(2-ethylhexyl) sulfosuccinate, which behaved indifferently, all additives reduced the conductivity of polypyrrole, some even by four orders of magnitude. Based on FTIR spectroscopy, it is proposed that the hydrophobic interactions and/or hydrogen bonding between the additives and growing polypyrrole chains play the important role in reducing chain ordering, while the ionic interactions have limited effect.

Comprehensive Characterization of Titania Nanotubes Fabricated on Ti–Nb Alloys: Surface Topography, Structure, Physicomechanical Behavior, and a Cell Culture Assay

In this study, hybrid composites based on β-alloy Ti-xNb and oxide nanotubes (NTs) have been successfully prepared. NTs of different sizes were grown on Ti-Nb substrates with different Nb contents (5, 25, and 50 wt %) via electrochemical anodization at 30 and 60 V. Scanning electron microscopy imaging revealed that vertically aligned nanotubular structures form on the surface of Ti-Nb alloy substrates and influence Nb content in alloys based on NT length. X-ray diffraction analysis confirmed the formation of the anodized TiO2 layer and revealed several phases as the Nb content increased, starting with α' for low Nb content (5 wt %), the martensite α″ for intermediate Nb content (25 wt %), and the β phase for the highest Nb content (50 wt %). Nanoindentation testing was used to evaluate the changes in mechanical properties of oxide NTs grown on Ti-Nb alloys with different compositions. NT arrays showed wide variations in Young's modulus and hardness depending upon the anodization voltage and the Nb content. The hardness and Young's modulus strongly correlated with NT morphology and structure. The highly dense morphology formed at a lower anodization voltage results in increased elastic modulus and hardness values compared with the surfaces prepared at higher anodization voltages. The nanostructurization of Ti-Nb surface substrates favored improved surface properties for the enhanced adhesion and proliferation of human mesenchymal stem cells (hMSCs). In vitro adhesion, spreading, and proliferation of hMSCs revealed the improved surface properties of the NTs prepared at an anodization voltage of 30 V compared with the NTs prepared at 60 V. Thus it can be concluded that NTs with diameters of ∼50 nm (at 30 V) are more favorable for cell adhesion and growth compared with NTs with diameters of 80 ± 20 nm (at 60 V). The surfaces of Ti-25Nb substrates anodized at 30 V promoted enhanced cell growth, as the further increase in Nb content in Ti-Nb substrate (Ti-50Nb) led to reduced cell proliferation. The application of NTs on Ti-Nb substrates leads to significant reductions in mechanical properties compared with those on the Ti-Nb alloy and improves cell adhesion and proliferation, which is vitally important for successful application in regenerative medicine.

Hexagonal g-C3N4 nanotubes with Pt decorated surface towards enhanced photo- and electro-chemistry performance

Layered carbon nitride (g-C3N4), as a kind of organic semiconductor used in term of photocatalysis, has been a research hot topic. In this article, few layered hexagonal g-C3N4 nanotubes was synthesized using bulk g-C3N4 as a precursor, the morphology is uniform and reveals wonderful reproducibility. Furthermore, hexagonal nanotube morphology of g-C3N4 promotes the electron transform following z axis and effectively separates photogenerated electron and hole, resulting in an outstanding H2 evolution performance, which is about 14 times high compared with g-C3N4 under visible light. In addition, due to electron moved following z axis, electrocatalytic hydrogen evolution activities also have been improved, especially for Pt modified hexagonal g-C3N4 nanotubes, its enhancement is eye-catching. Furthermore, the O-doped hexagonal g-C3N4 nanostructure could also obtained by using O-doped bulk g-C3N4 as precursor, and the photo- and electro-catalysis performance was further improved.

Physicochemical Properties of a Highly Efficient Cu-Ion-Doped TiO₂ Nanotube Photocatalyst for the Degradation of Methyl Orange Under Sunlight.

In this study, a series of copper-ion-doped titanium dioxide (Cu-ion-doped TiO₂) nanotubes (NTs) were synthesized via a hydrothermal method by the concentration variation of doped Cu ions (0.00, 0.50, 1.00, 2.50, and 5.00 mmol). In addition, the samples were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), nitrogen gas adsorption measurements, and ultraviolet-visible (UV-Vis) diffuse-reflectance spectroscopy. The photocatalytic activity of the Cu-iondoped TiO₂ NTs was investigated for the degradation of methyl orange (MO) under sunlight. The results obtained from the structural and morphological studies revealed that, at low concentrations of Cu-doped TiO₂ NTs, Cu is incorporated into the interstitial positions of the TiO₂ lattice, affording a new phase of TiO₂ (hexagonal) instead of the anatase TiO₂ (tetragonal) observed for undoped TiO₂ NTs. EDX analysis confirmed the presence of Cu in the TiO₂-based photocatalyst. All of the investigated samples exhibited a hollow fibrous-like structure, indicative of an NT morphology. The inner and outer diameters of the NTs were 4 nm and 10 nm, respectively. The photocatalysts exhibited a large surface area due to the NT morphology and a type IV isotherm and H3 hysteresis, corresponding to the mesopores and slit-shaped pores. The Cu-ion-doped TiO₂ NTs were excited by sunlight because of their low bandgap energy; and after the incorporation of Cu ions into the interstitial positions of the TiO₂ lattice, the NTs exhibited high visible-light activity owing to the low bandgap.

Microstructural Investigation of Nanocrystalline Hydrogen-Storing Mg-Titanate Nanotube Composites Processed by High-Pressure Torsion

A high-energy ball milling and subsequent high-pressure torsion method was applied to synthesize nanocrystalline magnesium samples catalyzed by TiO2 or titanate nanotubes. The microstructure of the as-milled powders and the torqued bulk disks was characterized by X-ray diffraction. The recorded diffractograms have been evaluated by the convolutional multiple whole profile fitting algorithm, which provided microstructural parameters (average crystal size, crystallite size distribution, average dislocation density). The morphology of the nanotube-containing disks has been examined by high-resolution transmission electron microscopy. The effect of the different additives and preparation conditions on the hydrogen absorption behavior was investigated in a Sieverts’-type apparatus. It was found that the ball-milling route has a prominent effect on the dispersion and morphology of the titanate nanotubes, and the absorption capability of the Mg-based composite is highly dependent on these features.

Structural and catalytic properties of copper silicate nanomaterials

Nanosized copper silicates with three different structural morphology (amorphous, nanotubes and MEL) were prepared using different synthesis methods. The physico-chemical properties of copper silicates were characterized by XRD, FT-IR, SEM, HRTEM, N2-physisorption, XPS and H2-TPR techniques. The results indicated that the preparation conditions affect reduction behavior and textural properties of nanosized copper silicates. Hydrothermal synthesis method yielded chrysocolla-like CuSiO3 nanotubes, which possessed high surface area and pore volume with easy reducibility. The catalytic performances of synthesized copper silicate nanostructures were evaluated for dehydrogenation of methanol. It was found that dehydrogenation activity is depended on the structural properties of copper silicates. Highest activity was observed for copper silicates with nanotube morphology. Catalytic dehydrogenation activity of copper silicates was also related to presence of more number of Cu-O-Si species, easy reducibility and Lewis acid centers. The CuSiO3 nanotubes sample also exhibited good stability under investigated reaction conditions that deactivation was not detected for 48 h.

A systematic investigation of dispersion concentration and particle size distribution of multi-wall carbon nanotubes in aqueous solutions of various dispersants

Surfactant-assisted exfoliation of multi-walled carbon nanotubes (MWNTs) in aqueous solution have become a common procedure to generate high fraction of individualized nanotubes. Since well-controlled experimental methodologies and reliable comparative metrics are scarce, a systematic research was conducted in order to analyze the dispersibility and the dispersing mechanisms of MWNTs in aqueous solutions of various surfactants. The concentration of dispersed MWNTs was accurately measured for a wide range of surfactant concentration, using combined UV–vis spectroscopy and thermogravimetric analysis (TGA). The obtained dispersibility results indicated that the highest dispersion concentration and efficiency is achieved in the SDBS-assisted MWNTs dispersion. Furthermore, the nanotube morphology and surfactant properties can be evaluated and rationalized by analyzing the dispersed nanotube mass and the surfactant amount per nanotube surface area. The amount of dispersed MWNTs remaining after varying levels of sonication and centrifugation was investigated, and a controllable sonication-centrifugation method for the preparation of well-dispersed MWNTs was established. The experimental data of the concentration of MWNTs dispersions versus centrifugation speed (ω) are fitted reasonably well by a Boltzmann function. The SDBS-assisted MWNTs dispersion will be more susceptible to the high centrifugal speed,while PVP-assisted MWNTs dispersion will be sediment fast at the mild centrifugation. The distributions of diameter and length of MWNTs at maximum dispersibility show that the sizes for the MWNTs dispersed by SDBS are much more polydisperse. The results further suggest that preparation of controllable carbon nanotubes morphology and design of rational configuration of surfactants are the key factors for increasing the dispersion stability and maximum concentration of well-dispersed MWNT.

Study of self-organized structure in carbon nanotube forest by fractal dimension and lacunarity analysis

In this work, a fractal analysis of a morphology of carbon nanotube (CNT) forest was conducted. A self-similarity between the formation of catalyst nanoparticles, low and high-density CNT forest growth, and Raman mapping was investigated, for a catalyst thickness of 0.8, 1.0, and 1.2 nm. To explain reasons behind fluctuations of the CNT forest structure, a fractal dimension (Df) and lacunarity (Λ) were calculated, using a box-counting method. During the fractality analysis of catalyst particles, the highest Df was obtained for the 0.8-nm-thick film (Df = 1.91), while the lowest one was noted for the Fe catalyst thickness of 1.2 nm (Df = 1.72). The progressive increase of the catalyst thickness affected the dewetting, Ostwald ripening and diffusion processes, affecting the catalyst size distribution and arrangement. The same thickness variation led to a similar decreasing trend of Df changes, which was observed in the planar and linear analysis of the distribution of CNTs and in the IG/ID ratio distribution in Raman mapping, confirming the complexity and the self-organizing properties of CNT forest. The self-similarity and scaling of properties of self-organized CNT forest structure were proved by the analysis of fractal dimension and lacunarity analysis and revealed different stages of the catalyst annealing.

Enhanced photocatalytic activity in TiO2 mixed phase nanostructures

Titanium dioxide (TiO2) is one of the most effective n-type semiconductors for photocatalytic applications. Compared with the bulk TiO2 nanostructures, the one-dimensional (1D) TiO2 nanostructures have elicited great interest due to its various advantageous properties such as high surface-volume ratio, high chemical stability, strong oxidizing power, nontoxicity and low cost. TiO2exists mainly in two crystalline phases namely anatase and rutile. When different phases of TiO2are combined, they have better charge transport and light absorption properties than pristine nanotubes and nanorods. In reference to that, mixed phases play an important role in the modification of the photocatalytic properties.In the present work, three different nanostructures (TiO2 nanotubes, nanorods and mixed phase nanohybrids) are fabricated by electrochemical anodization and hydrothermal processes, respectively. TiO2 nanotubes are synthesized by electrochemical anodization of highly pure titanium foil in a solution containing ethylene glycol, ammonium fluoride and distilled water, TiO2 nanorods are grown on fluorine-doped tin oxide (FTO) using a hydrothermal method and hybrid TiO2 nanostructures consisting of rutile TiO2 nanorods synthesized by hydrothermal method on anodized TiO2 nanotubes in a high temperature and high-pressure condition with titanium-n-butoxide as the reaction precursor. The three different morphologies of nanotubes, nanorods and nanohybrids are investigated using scanning electron microscopy (SEM). The crystallinity of the TiO2 nanotubes, nanorods and nanohybrids are studied using Raman spectroscopy and X-ray diffraction (XRD) techniques. TiO2 nanotubes, nanorods and nanohybrids are crystalized in anatase, rutile and mixed phase (anatase and rutile), respectively. The structural transformation of the formed TiO2 nanohybrid is compared with TiO2 nanorods and nanotubes that further be explored for photocatalysis by degradation of methylene blue (10 μM) under xenon lamp in the presence of catalysts. It is observed that overall photocatalytic activity of mixed phase TiO2 nanohybrids is better than TiO2 nanotubes and nanorods owing to better electron hole separation and transportation.

Effect of the structure and morphology of carbon nanotubes on the vibration damping characteristics of polymer-based composites.

The structure and morphology of the reinforcing material play an important role in the vibration damping characteristics of polymer composites. In this work, multiwalled carbon nanotubes (MWCNTs) with different structures and morphologies are incorporated into a polymer matrix. The vibration damping characteristics of the nanocomposites, in Oberst beam configuration, are studied using a free vibration test in cantilever mode. Inner tube oscillation is established as the vibration damping mechanism by correlating the extent of the loss factor obtained from the two nanocomposites with the dissimilarities in the structure and morphology of the two varieties of MWCNTs. Inner tube oscillation is simulated using molecular dynamics (MD). Since the open-ended double walled CNT (DWCNT) models used in earlier studies over predict the damping, we propose a capped DWCNT model. This can simulate the atomic interactions at the end caps of the tube. This study indicates that the contributions to the observed damping have their origins in the interaction between atoms that constitute the inner and outer tubes rather than the inter-tube frictional energy loss.

Carbon nanotubes synthesized on the surface of recycled carbon fibers by catalytic chemical vapor deposition for revalorization of degraded composite materials

There is a clear need to develop a sustainable use of composite materials; high-performance composite materials like carbon-epoxy systems are of special interest because of their wide range of applications and their high intrinsical value. Even though the technology for recycling thermoset composite materials has been developed, and the recovery of carbon fibers from composite materials is feasible, there is still to some extent, a degradation of the recovered carbon fibers; thus, a revalidation of the recycled carbon fibers with improved properties is highly desirable for a new life cycle in high-performance composites and components; thereupon, revalorization of the recovered carbon fibers by anchorage and growth of carbon nanotubes directly on the surface of the fibers via assembly of graphene-cap mechanism on nickel nanoparticles is an attractive technological approach for integral recycling of composite materials. These revalorized carbon fibers with carbon nanotubes are potential candidates for novel composites with exceptional mechanical, thermal, and electrical properties. In this research, catalytic chemical vapor deposition method was used for the synthesis of carbon nanotubes on the recycled fibers under influence of carbon source, temperature. Carbon nanotubes were produced by decomposing whether ethanol or isopropanol as a carbon source at temperatures ranging from 800 to 600 °C in an inert atmosphere. Fibers used as a substrate in this research are actually recovered carbon fibers from a carbon-epoxy composite component reaching end-of-life via pyrolysis. All experimental results were characterized using scanning electron microscopy corroborating the synthesis and morphology of the carbon nanotubes on the carbon fibers; Raman spectroscopy corroborated synthesis of multiwall carbon nanotubes; pseudo-mechanical testing confirmed that the nanotubes have a good anchorage to the carbon fiber surface, making this novel revalorized fiber a potential reinforcement for new high-performance composite materials.

Superficial treatment by anodization in order to obtain titanium oxide nanotubes applicable in implantology

Titanium and its alloys are the most popular metals applied on end osseous implants manufacturing. Commercially pure titanium (Ti c.p.) has been successfully used as a biomaterial because of its mechanical and chemical properties, excellent corrosion resistance and biocompatibility. In order to improve and accelerate the osseointegration process after implantation, superficial treatments are performed aiming properties that stimulate the growth of the newly-formed bone. In this work, self organized titanium dioxide (TiO2) nanotubes were obtained by anodic oxidation on Ti c.p. (grade 2). Also, it has been shown that the process is industrially reproducible for this purpose. As parameters for the anodizing process, it was concluded that the optimal electrolyte was H3PO4 solution + 0.15% HF under potentiostatic mode for 30 minutes. Potentials of 1, 5, 10, 15 and 20 V were tested in order to verify the best conditions to obtain nanotubes. In this case, potential was set at 10V. The morphology of the samples was characterized by Scanning Electron Microscopy (SEM), Scanning Electron Microscopy with Field Emission (SEM-FEG) and Atomic Force Microscopy (AFM). The results showed the nanotubes formation throughout the titanium samples surface. In accordance to the obtained roughness, it was observed that the formed nanotubes film is thin, however, the literature indicates that the film thickness is not relevant on the performance of nanostructures as optimizers of the osseointegration process, unlike the nanotubes morphology and diameter. In the wettability analysis, the nanotubes behaved as hydrophilic. Therefore, it is possible to obtain TiO2 nanotubes for using in implants by a superficial treatment, allowing a better osseointegration quality. Keywords: Titanium, Nanotubes, Anodization, Implants, Osseointegration.

Effect of Processing Temperature on the Morphology and Crystal Structure of Anodic TiO2 Nanotubes

In the present work, we have investigated the influence of temperature on the morphology of anodically produced self-organized titanium oxide nanotubes (TiNTs). TiNTs are synthesized by two-step anodization in ethylene glycol-based electrolytes containing ammonium fluoride and deionized water. Experiments are performed at constant anodization voltage of 50 V for 2 h. An investigation by the SEM images reveals that if the temperature is kept constant during the anodizing experiment, variation in the average tube diameter is significantly reduced. Degree of pore arrangement, pore size and oxide thickness increased with the increase in temperature as observed at a range of electrolyte temperatures fixed between 5°C and 40°C. However, if the temperature is not controlled during the anodization experiment, then due to the exothermic nature of the reactions to the formation of TiNTs, the temperature of the electrolyte continues to increase. This variation in electrolyte bath temperature introduces strong variations in tube diameter (10–160 nm) along the length of the tubes. Current profiles, recorded during the anodization experiments, predict the effect of constant and varying experimental temperatures as well. In both cases, XRD results show the complete anatase crystal structure of nanotubes upon annealing at 450°C. The present work highlights the importance of fixed processing temperature during the anodization experiments in order to develop an ordered array of nanotubes with a uniform tube diameter.