Anodic Titania Nanotube Research Articles

Large-Scale, Uniform, and Superhydrophobic Titania Nanotubes at the Inner Surface of 1000 mm Long Titanium Tubes

Large-scale and mass production of uniform nanostructured materials has been a growing challenge. Anodic titania nanotubes have been widely employed in various applications, which are usually demonstrated with limited size and planar geometry. In this study, a coaxial electrochemical anodization approach is explored and reported. With this method, uniform titania nanotube arrays are produced at the inner surface of titanium tubular electrodes of 1000 mm in length and 10 mm in diameter, in good contrast to the nonuniform nanotubes attained with a conventional anodizing scheme. Such an approach is cost-effective and energy-efficient. It is also capable of processing other valve metals possible for anodization and even longer tubular substrates. The wetting property of the resulting nanotube arrays is further tailored, with a maximum contact angle of 166° for water and 163° for glycerol, exhibiting a superhydrophobic feature. An equation is derived to compute the intrinsic contact angle of a spherical drople...

Glypican-based drug releasing titania implants to regulate BMP2 bioactivity as a potential approach for craniosynostosis therapy

Advances in molecular biology and nanomedicine based therapies hold promise to obviate the need of multiple surgical interventions (associated with current management) in craniosynostosis by preventing bone re-ossification. One such adjunctive therapy involves application of glypicans 1 and 3 (GPC1 and GPC3) that are BMP inhibitors implicated in downregulating the BMP2 activity in prematurely fusing sutures. Electrochemically anodized Titania nanotube (TNT) arrays have been recognized as a promising localized, long-term drug delivery platform for bone-related therapies. This study presents the application of nanoengineered TNT/Ti implants loaded with recombinant glypicans for craniosynostosis therapy. By using Dual luciferase Reporter assay, we tested the biofunctionality of eluted glypicans from the TNT/Ti implants for BMP2 bioactivity regulation in C2C12 murine myoblast cell line. BMP2 activity was inhibited significantly for up to 15days by the glypicans released from polymer-coated TNT/Ti implants, indicating their potential application in adjunctive craniosynostosis treatment.

Characterization of Pulse Anodized Titanium Dioxide Nanotubes

TiO2 nanotubes with a highly ordered structure were grown by a self-organized electrochemical anodization in the viscous organic electrolyte. The alteration pulse anodization waveforms were applied. The applied potentials were between positive of 20 V 10 min and a reverse voltage of 0 V or -5 V 20 sec. The morphologies of samples were examined using a field emission scanning electron microscope and focused ion beam field emission scanning electron microscopes (FIB-FESEM). The crystalline structures of the TiO2 nanotubes were confirmed by X-ray diffraction. The UV–Vis diffuse reflection absorption were recorded by a UV–vis spectrometer. All TiO2 nanotube samples prepared by pulse anodization technique were anatase phase and responded to UV region. The best-defined TiO2 nanotube morphology was obtained from the anodization condition: 20 V 10 min/-5 V 20 sec for 1 h. The thickness of the oxide layer increased with the increasing anodization time. All eight TiO2 nanotube samples responded to the light in the wavelength ranging from 190-360 nm which was UV region indicated the good photocatalytic property of these materials. Properties of anodized titanium dioxide nanotube from this work can be the useful indicators for the responsiveness of ultraviolet light which enhances the good property in photocatalytic process.

A Study on Homocysteine Biosensors Completely Constructed on Anodized Titania Nanotubes

Homocysteine biosensors, based on titania nanotubes as a two-electrode system, were studied herein. The working electrode used was an immobilization of a D-amino acid oxidase enzyme by glutaraldehyde on titania nanotubes, and the reference electrode was a titania nanotube. The structure showed a reversible reaction in an electrochemical analysis. Similar cyclic voltammetry indicated that the sensitivity was 53.4 nA/μM, the corresponding correlation coefficient of linearity R 2 was 0.998 in a detecting range from 0 and 70 μM, and the limit of detection was about 1.5 μM.

Hierarchical in Situ functionalized TiO2 Nanotubular Substrate for Sensing Volatile Organic Compounds Associated with Tuberculosis

Mycobacterium tuberculosis (MTB) is a devastating disease that effects over 10 million people worldwide with approximately 1.8 million deaths1. One major issue contributing to this wide spread disease is lack of low cost point-of-care methods for screening/diagnosis of the disease. One method that has gained a significant amount of attention is the use of volatile organic compounds (VOCs) found in the breath of patients as a biomarker for the disease. These VOCs include methyl nicotinate and methyl p-anisate which are unique metabolic byproducts of the microorganism. To take advantage of the presence of these VOCs, a hierarchical in situ functionalized TiO2 nanotubular substrate has been synthesized to specifically detect methyl nicotinate and methyl p-anisate in a complex sample. These VOCs can be detected at very low levels using a solid-state sensor based on metal-functionalized 3D titanium dioxide (TiO2) nanotube arrays that bind the biomarkers at a specifically applied voltage. When a VOC of interest approaches the sensing substrate, it binds preferentially with the metal on the surface of the TiO2 nanotubes causing a large change in current (from nanoamp to microamp range). Our previous research has shown that a TiO2 nanotube array substrate functionalized with cobalt using wet incipient methods is capable of specifically detecting the MTB VOCs2-4. However, the sensor performance in this prior work, while promising, can be improved in terms of reliability, response time, and signal to noise ratio. The structure and consistency of the TiO2 sensing substrate is extremely important and methods for its improvement are constantly explored. In this work, we improve the MTB VOC sensors response time and accuracy by using a two-step method in the anodization process to create a hierarchical in situ functionalized TiO2 nanotubular substrate. In the first step, titanium metal was anodized for 30 minutes at 60V. In the second step the substrate was anodized at 30 V for 60 minutes. This process results in a hierarchical nanostructure composed of nanotubular and honey comb shapes (Figure 1). The smaller nanotubes inside each honeycomb shape structure are the result of anodizing at lower voltage. The two-step method of anodizing makes highly organized interconnected nanotubes and allows for improved sensor reliability when measuring current. In addition, we can improve our sensor respond to methyl nicotinate and methyl p-anisate by functionalizing the sensor while anodizing it (in situ functionalization). In this work cobalt was added to the anodizing solution resulting in the cobalt metal being integrated into the hierarchical nanostructure. The advantage of this approach is the reduction in sensor synthesis steps when compared to our previous work, and improved sensor response. Detailed analysis of nanostructured synthesis and sensor performance will be presented. 1. Tuberculosis (TB) Data and Statistics. https://www.cdc.gov/tb/statistics/ Accessed 12/16/2016, 2016. 2. Bhattacharyya D, Smith YR, Misra M, Mohanty SK. Electrochemical detection of methyl nicotinate biomarker using functionalized anodized titania nanotube arrays. Materials Research Express 2015;2(2):025002. 3. Bhattacharyya D, Smith YR, Mohanty SK, Misra M. Titania Nanotube Array Sensor for Electrochemical Detection of Four Predominate Tuberculosis Volatile Biomarkers. Journal of The Electrochemical Society 2016;163(6):B206-B214. 4. Smith YR, Bhattacharyya D, Mohanty SK, Misra M. Anodic functionalization of Titania nanotube arrays for the electrochemical detection of tuberculosis biomarker vapors. Journal of The Electrochemical Society 2016;163(3):B83-B89. Figure 1

Improved performance of anodic titanium oxide nanotube arrays synthesized by sonoelectrochemical anodization method for dye-sensitized solar cells

With rising demand for using solar cell systems for energy and environmental applications, considerable interest in anode materials of these cells has dramatically emerged. In this work, TiO2 nanotubular electrodes of varying thicknesses as anode were fabricated using effective process in a short time by sonoelectrochemical anodizing of Ti using an organic electrolyte, containing Na2[H2EDTA]. Long TiO2 nanotubes about 30–40 μm thick containing ordered hexagonal TiO2 were achieved through manipulating anodization parameters. Dye-sensitized solar cells (DSSCs) with different TiO2 electrode morphologies of varying thicknesses were compared to DSSCs based on TiO2 Nanoparticle electrodes. The effect of controlling parameters of the sonoelectrochemical process including surface preparation and anodizing time was investigated. This report brings to attention the desirable properties of the structurally oriented TiO2 for dye-sensitized solar cell applications. It found that the best cell performance was achieved about 3.14% in the case of using TiO2 NT layers that were treated by TiCl4 treatment.

Improved in vitro angiogenic behavior on anodized titanium dioxide nanotubes

BackgroundNeovascularization over dental implants is an imperative requisite to achieve successful osseointegration onto implanted materials. The aim of this study was to investigate the effects on in vitro angiogenesis of anodized 70 nm diameter TiO2 nanotubes (NTs) on Ti6Al4V alloy synthesized and disinfected by means of a novel, facile, antibacterial and cost-effective method using super oxidized water (SOW). We also evaluated the role of the surface roughness and chemical composition of materials of materials on angiogenesis.MethodsThe Ti6Al4V alloy and a commercially pure Ti were anodized using a solution constituted by SOW and fluoride as electrolyte. An acid-etched Ti6Al4V was evaluated to compare the effect of micro-surface roughness. Mirror-polished materials were used as control. Morphology, roughness, chemistry and wettability were assessed by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy, atomic force microscopy, energy dispersive X-ray spectroscopy (EDX) and using a professional digital camera. Bovine coronary artery endothelial cells (BCAECs) were seeded over the experimental surfaces for several incubation times. Cellular adhesion, proliferation and monolayer formation were evaluated by means of SEM. BCAEC viability, actin stress fibers and vinculin cellular organization, as well as the angiogenic receptors vascular endothelial growth factor 2 (VEGFR2) and endothelial nitric oxide synthase (eNOS) were measured using fluorescence microscopy.ResultsThe anodization process significantly increased the roughness, wettability and thickness of the oxidized coating. EDX analysis demonstrated an increased oxygen (O) and decreased carbon (C) content on the NTs of both materials. Endothelial behavior was solidly supported and improved by the NTs (without significant differences between Ti and alloy), showing that endothelial viability, adhesion, proliferation, actin arrangement with vinculin expression and monolayer development were evidently stimulated on the nanostructured surface, also leading to increased activation of VEGFR2 and eNOS on Ti6Al4V-NTs compared to the control Ti6Al4V alloy. Although the rougher alloy promoted BCAECs viability and proliferation, filopodia formation was poor.ConclusionThe in vitro results suggest that 70 nm diameter NTs manufactured by anodization and cleaned using SOW promotes in vitro endothelial activity, which may improve in vivo angiogenesis supporting a faster clinical osseointegration process.

Influence of Formation Conditions on the Level of Arrays Ordering of Anodic Titanium Oxide Nanotubes

Nanotubular titanium oxide coatings with different morphology and dimensional parameters are formed by anodic oxidation under different voltage and time modes in fluorine aqueous-nonaqueous electrolytes containing glycerin as well as several surface-active agents (SAA). Their morphological peculiarities are examined and qualitative and quantitative analysis of obtained types of ordering is carried out, geometric configuration entropy are calculated on the base of analysis SEM images and theory of self-organization.

Fabrication and Characterization of Front-Illuminated Dye-Sensitized Solar Cells with Anodic Titanium Oxide Nanotubes

We have fabricated front-side illuminated dye-sensitized solar cells (DSSCs) with a thin film of vertically oriented TiO2 nanotubes used as the negative electrode. The TiO2 nanotube film was formed by anodizing a metallic titanium thin film that was deposited on a transparent conductive oxide (TCO) layer with an intermediate, protective TiO2 layer. We characterized the structural and electronic properties of the formed TiO2 nanotube films. Titanium tetrachloride (TiCl4) treatment was applied on the TiO2 nanotube film to improve the performance of the DSSCs. We have investigated effects of TiCl4 treatment on the solar cell parameters of the DSSCs: short-circuit current density (ISC), open-circuit voltage (Voc), ideal factor (n), series resistance (Rs) and shunt resistance (Rsh). The parameters have been derived by analyzing measured I-V characteristic of the DSSCs on the basis of the method we have previously proposed. We demonstrate that the performance of the DSSCs is improved by TiCl4 treatment. We discuss the effects of TiCl4 treatment on the performance on the basis of the derived cell parameters.

Nano-structural variation of highly aligned anodic Titania nanotube arrays for gas phase photocatalytic application

Abstract Highly aligned titania (TiO 2 ) nanotube (NT) arrays have been grown on titanium sheet by using a self organized anodic oxidation method at different potentials (34–74 V) in a NH 4 F and ethylene glycol based electrolyte. Two sets of TiO 2 NT arrays have been fabricated with and without using cooling systems. Without cooling system, the solution temperature is increased from 25 °C (room temperature) to 63 °C with increase of anodization potential from 34 to 74 V. The temperature has been maintained to 25 °C by using water based cooling system. In both sets of samples, the pore diameter of TiO 2 NT arrays increases with increase of anodization potential. The maximum pore diameter has been (outer: 224 nm, inner: 172 nm) achieved with TiO 2 NT arrays (at 74 V) without using cooling system. The photocatalytic activity of the TiO 2 NT arrays is evaluated by the decomposition of methanol by the use of Fourier transform infrared spectrophotometer. The TiO 2 NT (at 44 V) sample has been fabricated without using cooling system, which shows the higher photocatalytic activity than the sample at other potentials. Using cooling system, the TiO 2 NT (at 54 V) sample shows the higher photo-decomposing property than the sample at other potentials. The TiO 2 NT (at 54 V) sample with cooling system shows the higher rate (photocatalytic activity) constant ( k = 0.0216) than the TiO 2 NT (at 44 V) sample without using cooling system ( k = 0.0186). The photocatalytic activity has been correlated with the nanostructural variation of TiO 2 NT arrays at different potentials without (self-grown solution temperature) and with water based cooling systems.

Effect of silane-coupling modification on bioactivity and in vitro properties of anodized titania nanotube arrays

Titanium dioxide nanotube arrays (TNTs) were fabricated by anodization method on Titanium (Ti) substrate then hydrothermally functionalized with γ-glycidoxypropyltrimethoxysilane (GPTMS) to study the synergetic effect of both nanotopography and chemical cues of TiO2 based nanotubes on the cellular behavior and bioactivity property. As a result, the bare anatase TNT and functionalized with GPTMS demonstrated great potential in promoting the proliferation, adhesion of osteoblast cells with excellent biocompatibility and enhanced the bioactivity than conventional and polished Ti surface.

Improved photoanode structure based on anodic titania nanotube array covered by TiO2-NPs/nanographite composite layer for ETA-cells

This work is devoted to the morphology and electrical properties optimization of flexible photoanodes based on anodic titanium oxide nanotubular arrays (TiO2-NTAs) for solar cells with extremely thin absorbing layer (ETA-cells) by TiO2-nanographite thin composite layer formation on the TiO2-NTAs surface. First, the carbon doped TiO2-NTAs were synthesized by annealing of the as-anodized TiO2-NTAs in argon without foreign carbonaceous precursor. The residual ethylene glycol absorbed on the nanotube wall during anodization serves as the carbon source and the C species are uniformly distributed along the entire nanotube to form the C-TiO2 NTAs. Further decorating of C-TiO2-NTAs surface by TiO2 nanoparticles to form the TiO2-nanographite (NG) composite layer with high conductivity and increased photoanode effective area showed improved ETA-cells performance.

The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

Anodic titanium dioxide nanotube (TNT) arrays have wide applications in photocatalytic, catalysis, electronics, solar cells and biomedical implants. When TNT coatings are combined with severe plastic deformation (SPD), metal processing techniques which efficiently improve the strength of metals, a new generation of biomedical implant is made possible with both improved bulk and surface properties. This work investigated the effect of processing by high pressure torsion (HPT) and different mechanical preparations on the substrate and subsequently on the morphology of TNT layers. HPT processing was applied to refine the grain size of commercially pure titanium samples and substantially improved their strength and hardness. Subsequent anodization at 30V in 0.25wt.% NH4F for 2h to form TNT layers on sample surfaces prepared with different mechanical preparation methods was carried out. It appeared that the local roughness of the titanium surface on a microscopic level affected the TNT morphology more than the macroscopic surface roughness. For HPT-processed sample, the substrate has to be pre-treated by a mechanical preparation finer than 4000 grit for HPT to have a significant influence on TNTs. During the formation of TNT layers the oxide dissolution rate was increased for the ultrafine-grained microstructure formed due to HPT processing.

Enhanced electrochemical performance of TiO2 nanotube array electrodes by controlling the introduction of substoichiometric titanium oxides

Although anodized titania nanotubes (TNTs) possess unique advantages as an electrode material, the poor electrical conductivity limits their practical application. We herein report a facile route to enhance electrical conductivity and improve electrochemical behavior by controlling the introduction of substoichiometric titanium oxides (TinO2n-1), which can facilitate charge propagation in TNTs and improve kinetics of ions and electron transport in the electrode. Specific capacitance is as high as 3.77 mF cm−2, which is about 47 times higher than that of the untreated samples (0.08 mF cm−2). Galvanostatic charge-discharge results show TNT arrays-based electrode stable capacitance behavior with excellent capacitance retention even after 1000 continuous charge-discharge cycles at a current density of 50 μA cm−2 in Li2SO4 electrolyte. The ease of synthesis and the superior electrochemical performance suggest a promising application for the TNT arrays-based material in energy storage field.

Interdigitated CuS/TiO2 Nanotube Bulk Heterojunctions Achieved via Ion Exchange

In photovoltaic and optoelectronic applications, a three-dimensional bulk heterojunction is highly desirable in view of the large interfacial area for rapid charge separation. An additional benefit of oriented charge transport is furnished when using anodized titania nanotube arrays as the substrates. However, filling the nanotubes with another p-type semiconductor integrate film, rather than discrete nanoparticles, is difficult with solution-based process. In this study, an interdigitated CuS/TiO2 bulk heterojunction was achieved by filling up TiO2 nanotube arrays with ZnS nanoparticles, and subsequently converting the ZnS nanoparticles into CuS film. Such a combination of pre-filling and post-exchanging process is essential in formation of the interdigitated structure. The rational design of the unique architecture demonstrated in this work provides a facile and general approach to fabricate bulk heterojunctions with other potential semiconductors.

Wettability Switch of Anodic Titanium Dioxide Nanotubes with Various Diameters

Surface topography and physicochemical properties such as adhesion, cohesion and wettability is presumed to alter/facilitate the protein binding, cell adhesion and proliferation, thereby reducing post-operative complications with increased lifespan of biomedical implants.1 Current study examines the ageing behaviour of titanium dioxide (TiO2) nanotubes with various diameters and their switch in wettability by gaseous plasma treatment.Self-organized TiO2 nanotube layers were fabricated according to the electrochemical anodization method published earlier.2 The ethylene glycol based electrolytes were used for growing the nanostructures which contains specific amount of water and specific concentration of hydrofluoric acid. Anodization parameters such as applied voltage as well as experimental time were optimized to get desired diameters (15nm, 50nm and 100nm) of TiO2 nanotubes. As-anodized surfaces are hydrophilic and tend to age with time to more hydrophobic. Water contact angle measurements were performed during seven weeks period to study ageing behaviour as well as switch in wettability after gaseous plasma treatment. All the contact angle measurements were performed with demineralized water. The contact angle was measured by fitting the water drop on the surface. Surface wettability indeed switched after plasma treatment as the surface became hydrophilic. Changes in wettability after ageing were explained by organic contamination from ambient atmosphere, while hydrophilic character was obtained after plasma treatment due to removal of these contaminants. Moreover storing the samples in sealed container also influenced on their ageing profile.This current work provides solution and guidelines by which switch in wettability of TiO2 nanotubes can be achieved and can be employed in medical applications where hydrophilic character is desired for specific application, such as orthopedic implants.

Communication—Ultrafast Anodized Titania Nanotube Arrays Loaded with Quantum Dots via Ultrasonic Assistance

Self-aligned and firmly-structured titania nanotube arrays (TNAs) with excellent photoelectric response were fabricated by anodization in tens of seconds. Furthermore, TNAs were decorated with CdS quantum dots by ultrasonic-assisted successive ionic layer adsorption and reaction (U-SILAR) method. The resulted CdS/TNAs hybrid shows higher visible light absorption, stronger photo current and stable structure than those of the sample by traditional SILAR method.

Electrochemical preparation of tin–titania nanocomposite arrays

The first successful electrodeposition of Sn inside self-organized anodic titania nanotubes.

Anodic Functionalization of Titania Nanotube Arrays for the Electrochemical Detection of Tuberculosis Biomarker Vapors

Anodic titania nanotube arrays have been extensively explored for gas sensing applications due to their high chemical and thermal stability and robust synthesis method. In this study, we explore the use of functionalized titania nanotube arrays for the electrochemical detection of gaseous volatile organic biomarkers associated with tuberculosis. The synthesis method developed allows for in situ functionalization of titania nanotubes with oxygen containing metal species (i.e., Co(OH)2) during anodization. Amperometric detection of volatile organic biomarkers with concentrations of 275 ∼ 360 ppm using next generation titania nanotubes functionalized with Co(OH)2 where compared with Co(OH)2 functionalized titania nanotubes via a wet incipient method. Improved sensor response and sensitivity was observed with next generation titania nanotubes, which can be attributed to homogeneous distribution of reactive sites directly in contact with the parent titania. A mechanism for sensor response and in situ functionalization is presented.

Hydroxyapatite based and anodic Titania nanotube biocomposite coatings: Fabrication, characterization and electrochemical behavior

The main challenges of biological implants are suitable strength, adhesion, biocompatibility and corrosion resistance. This paper discusses fabrication, characterization and electrochemical investigation of anodized Ti6Al4V without and with a hydroxyapatite (HA) layer, HA/TiO2 nanoparticles (NPs) and HA/TiO2 nanotubes (HA/anodized). X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS) were used to characterize and compare properties of different samples. Dense HA with uniform distribution and 12.8 ± 2 MPa adhesive strength enhanced to 19.2 ± 4 MPa by the addition of TiO2 nanoparticles and enhanced to 23.1 ± 4 MPa by the deposition of a TNT interlayer was fabricated by an anodic oxidation process. EIS analysis divulged the polarization behavior of various layers formed on a Ti6Al4V substrate. Electrochemical measurements indicated polarization passivation due to incorporation of TiO2 nanoparticles to HA. Hydroxyapatite on a TNT layer revealed lower corrosion resistance than a HA/TiO2 nanoparticle sample due to the vacuolar nature of TNT conformation. The passivation current density of the Ti6Al4V alloy coated with a HA/TiO2 nanocomposite (0.125 μA/cm2) was less than 1% of the bare substrate.