Nanotubular Films Research Articles

Stabilized Brookite Nanotube Array Films Grown on Transparent Substrates for Photoelectrochemical Water Splitting

Photoelectrochemical water splitting is a promising route to realizing a clean energy economy. Herein, we report on the ability to selectively fabricate optimized Ni-doped brookite nanotube array films on fluorine-doped tin oxide (FTO) substrate using ultrarapid radio frequency sputtering followed by electrochemical anodization and thermal annealing under ambient air. Ni doping promotes photocatalytic performance by introducing impurity bands within the TiO2 bandgap. Further, annealing at various temperatures helps to tune the photoactivity of the fabricated photoelectrodes, which is in agreement with the nature of the trap states. The nanotubes enjoy high crystallinity and enhanced photoresponse with a noticeable bandgap of 2.7 eV. The Mott–Schottky analysis reveals the variation in the charge carriers density of the fabricated nanotubes. Most importantly, the electrochemical impedance spectroscopy (EIS) analysis unravels the involved kinetics and helps to determine the charge transfer properties of the annealed nanotubular films under open-circuit voltage (OCV) and with applied potential under dark and illumination conditions. EIS analysis reveals decreased charge transfer resistance under illumination, in agreement with the obtained photocurrent, electron lifetime, and density of trap states.

Removal of Persistent Acid Pharmaceuticals by a Biological-Photocatalytic Sequential Process: Clofibric Acid, Diclofenac, and Indomethacin

The removal of three acid pharmaceuticals—clofibric acid (CLA), diclofenac (DCL), and indomethacin (IND)—by a biological-photocatalytic sequential system was studied. These pharmaceutical active compounds (PhACs) are considered to persist in the environment and have been found in water and sewage, producing adverse effects on the aquatic environment. For the biological process, in batch experiments, a fixed bed bioreactor and activated sludge (hybrid bioreactor), under aerobic conditions, was used as pretreatment. The pretreated effluent was exposed to a photocatalytic process employing TiO2 nanotubular films (NTF-TiO2) with the following characteristics: an internal diameter of 112 nm, a wall thickness of 26 nm, nanotube length of 15 µm, a roughness factor of 1840 points, and an anatase-rutile crystalline structure. In the hybrid bioreactor, 39% IND and 50% ACL and DCL were removed. The biological-photocatalysis sequential system achieved the degradation of up to 90% of the initial concentrations of the three acid pharmaceuticals studied. This approach appears to be a viable alternative for the treatment of these non-biodegradable effluents.

Use of nanotubular TiO2 films for the photo-degradation of emerging contaminants (drugs) in water


 Provide in a single paragraph of 300 words maximum an overview of the work, including background, methodology, main results, and conclusions. One of the biggest problems of the 21st century is perhaps the need to provide water for the growing world population. Faced with this global problem around water, pollution is a factor of great importance, since the pollutants generated by industrial and domestic activity can be accumulated and transported by both surface and underground waters, deteriorating their quality. Therefore, it is necessary to study the behavior of these pollutants in water and propose treatment techniques that can eliminate them.
 
 
 Regarding water treatment techniques, it has been shown that heterogeneous photocatalysis with TiO2 is a clearly effective and environmentally an advantageous alternative for the removal of organic substances in aqueous media. In photocatalysis degradation processes, the analysis of the influence of the surface phenomena on the degradation reactions is of special interest.
 
 
 In the present work, the preparation of TiO2 self-ordered nanotubular films was carried out by means of the electrochemical anodization technique using the electrolyte: 50% Vol. Glycerol + 50% Vol. H2O + NH4F [0.27M), to be utilized in a Photocatalytic Reactor (FR) for the photodegradation of Metoprolol in order to evaluate the efficiency of the heterogeneous photocatalytic as an Advanced Oxidation Processes (AOP) through the photodegradation of the emerging pollutant under study and determine the efficiency of the photodegradation through the technique of gas chromatography coupled to mass spectrometry (GC-MS).

Zirconia nanotube coatings - UV-resistant superhydrophobic surfaces

Surface modifications influence material interactions such as wettability, imparting hydrophobicity or hydrophilicity. Mainstream research focused on enhancing product shelf-life directs attention towards superhydrophobic surfaces (SHS). SHS offer several benefits for out-door applications such as self-cleaning, anti-soiling, anti-mist etc. Recently, such surfaces were created by hydrophobization of anodized titania, which although effective lacked a long-term stability of their hydrophobic modifications due to it being susceptible to UV-mitigated degradation. In light of this situation, ZrO2-nanotubes are evaluated with regard to their application as transparent UV-stable superhydrophobic coatings. Nanostructured oxide surfaces are created via single-step electrochemical anodization. The absence of HF acid-based pre-etching steps offer a safe and alternatively a green synthesis route. Anodized oxides are modified using octadecylphosphonic acid (OPA) self-assembled monolayers, demonstrate superhydrophobicity and are at par with conventionally employed coatings such as PTFE, PFDPA and PTES. The OPA-coatings are evaluated for their mechanical stability under a jet of water, chemical stability under indirect sunlight irradiation in air/water and direct UV exposure. Zirconia nanotubular films were evaluated for optical transparency using light microscopy and surface wettability of the different zirconia-composites was compared to the model system - titania. Structural and compositional differences of the SAM layer upon time dependent decay were analyzed with X-ray photoelectron spectroscopy.

Synthesis and Attestation of Titanium Dioxide Nanotubes Based Photocatalyst for Water and Air Purification out of Harmful Organic Impurities

In the present work we have synthesized nanotubular TiO2 film with a nonstoichiometric layer in the vicinity of titanium foil by anodization during 120 min. The catalytic activity of nanotubular titanium dioxide films formed during the oxidation of acetone to carbon dioxide under the action of visible light with a wavelength of 450 nm was found to be approximately 2 times higher compared to standard titanium dioxide (Degussa P25). Such a pronounced enhancement of activity may be attributed to a more efficient absorption of visible light by the films due to narrowing of the optical gap because of difference in the nonstoichiometry of titanium dioxide near the interface between nanotubular film and the titanium foil substrate.
 Keywords: photocatalysis, nonstoichiometric titanium dioxide, purification of water

Formation of quasi-spherical Au48-198 clusters in anodic titania nanotubes grown on Ti-Au alloys

The effect of alloying sputter-deposited Ti with 2 at.% of Au on the growth of anodic nanotubes was studied in monoethylene glycol electrolyte containing 1.0 mol dm−3 of water and 0.1 mol dm−3 of ammonium fluoride. The classic shape of nanotubes modified with quasi-spherical clusters of Au48-198 was obtained on Ti-Au (2 at.%). The results were compared to the formation of a barrier-type anodic film which suggested that gold located at the alloy/anodic film interface is enriched as a consequence of the preferential oxidation of titanium during the prior anodizing period and transported to the cell boundary region of the nanotubular film in the form of quasi-spherical clusters of Au48-198. A consequence of the inclusion of Au48-198 in the structure of the nanotubes was a reduction in the rate of nanotubular film growth due to the generation of oxygen catalysed on the clusters. A further increase in gold content up to 8 at.% in the alloy resulted in the formation of sponge-like or nanoporous anodic layers, with the structure depending on electrolyte composition.

Sn-doped TiO2 nanotubular thin film for photocatalytic degradation of methyl orange dye

We fabricated Sn-doped TiO2 nanotubular film via annealing of anodized TiO2 nanotubes grown on F–SnO2 (FTO) glass. Annealing was carried out at 500 °C in ambient air. Anatase crystal structure was achieved with no change in nanotubular morphology in respect to as-anodized amorphous TiO2 nanotubes. The X-ray photoelectron spectroscopy analysis revealed Sn on the surface of TiO2 film, following the thermal treatment, probably caused by the diffusion from FTO glass. Depth profile examination of the film chemical composition was conducted by elastic recoil detection analysis, which showed that in addition to the diffusion of Sn from FTO, diffusion of Ti to FTO concurrently occurred. Thus, a higher concentration of Sn was found at the bottom of the tubes, while a lower concentration was present on the tubes’ surface top. This explains the improved optical response revealed by a diffuse reflectance spectroscopy. The absorption enhancement demonstrated that Sn-doped TiO2 film was efficient in the degradation of methyl orange dye under visible light.

Influence of Anodization-Electrolyte Aging on the Photocatalytic Activity of TiO2 Nanotube Arrays.

TiO2 nanotubular films prepared using the anodic oxidation process applied to various forms of metal titanium are promising materials for photocatalytic applications. However, during successive anodizations in batch-anodization cells, the chemical composition of the NH4F- and water-based ethylene glycol electrolyte changes with each subsequent anodization, which greatly affects the final photocatalytic properties of the annealed TiO2 nanotubular films. In the present study, 20 titanium discs (Φ 90 mm) were sequentially anodized in the same anodization electrolyte. The chemical composition of the electrolyte was measured after each anodization and correlated with the anodization current density, temperature, electrical conductivity, and pH of the electrolyte and with the morphology, structure, composition, and photocatalytic activity of the resulting TiO2 nanotube films. It was found that the length of the TiO2 nanotubes decreased with the age of the electrolyte due to its lower conductivity. The subsurface chemical composition was evaluated by time of flight secondary ion mass spectrometry (ToF SIMS) analyses, and the integrated ToF SIMS signals over a depth of 250 nm for the TiO2 nanotube films showed that the concentration of F– in the annealed TiO2 film increased with each subsequent anodization due to the increased pH value of the electrolyte. As a consequence, the concentration of the OH– and O2– species decreased, which is a major reason for the reduced photocatalytic activity of the TiO2 films. It is proposed that the length of the TiO2 nanotubes does not play a decisive role in determining the photocatalytic activity of the TiO2 nanotube films. Finally, the best measured degradation results of 60% for caffeine were thus achieved for the first anodized titanium discs. After that the efficiency gradually decreased for each subsequent anodized disc.

(Invited) Formation, Characterization and Applications of Nanowire Films Formed By Anodizing of Metals

Anodizing of metals and alloys is a simple electrochemical process to form various nano-structured oxide films, including self-ordered nanoporous and nanotubular films. Typical examples are nanoporous alumina films with honeycomb morphology and nanotubular array of anodic titanium oxide. Recently, several nanowire-type anodic films have been prepared on metals, including aluminum, copper and zinc. The formation mechanism of of the nanowire films may be different from those of the nanoporous and nanotubular anodic films. Here, our recent studies on the formation, characterization and applications of the anodic nanowire films on metals are presented. When zinc plate was anodized at a constant voltage in KHCO3 aqueous electrolytes, nanowires were covered on the entire zinc surface. From the SEM observations, it was found that pits were initially formed on zinc surface. The low-voltage SEM observations disclosed that some small pits were covered with a thin passive film, and in such pits nanowires were preferentially nucleated probably because of the increased concentration of dissolved Zn2+ ions in the pits. Then, the nanowires were grown radially over the pits and covered the entire zinc surface. The nanowires were not composed of ZnO. XPS and FT-IR analyses of the nanowire films indicated the presence of carbonate and hydroxide species; the nanowire consisted of basic zinc carbonate. TEM observations confirmed the single crystalline nature of the as-formed nanowires. The basic zinc carbonate was converted to ZnO without changing the nanowire morphology by heat treatment in air, although single crystalline nanowires changed to polycrystalline one. In addition, slit-type nanopores were introduced into the nanowires so that the specific surface area of the nanowire films was highly enhanced by the heat treatment. The nanowire films exhibits unique wettability to liquids. The as formed nanowire films showed superhydrophilicity with a water contact angle close to 0o and after organic coating the surface changed to superhydrophobic with a water contact angle greater than 150o. Such surface may have many potential applications.

ITUG and TUG with dual task for falls risk in stroke patients

The synthesis of TiO2 nanotubular films is presented together with their physical, chemical, electrochemical and photoelectrochemical characterization in order to assess their use as photocatalyst. The synthesis was made through the anodic oxidation procedure using an inorganic fluoride based electrolyte. The nanotubes presented an inner diameter of 54 nm, a wall thickness of 18 nm and a length of 570 nm in amorphous condition. After annealing at 500 °C the alignment and definition of the nanotubes were improved observing more space between the nanotubes, contrary to that observed at 700 °C, in which a detrimental morphology was seen, presenting a disruption of a little portion of the superior edge of the nanotubes. The electrochemical characterization was made for four samples: the amorphous one and two crystallized samples at 500 (TNTC-5) and 700 °C (TNTC-7) and for Ti. The TNTC-5 (constituted by anatase-rutile) which improved its morphology and kept its mechanical strength after annealing, presented the best electrochemical stability after 5 days of exposure. In conclusion, TNTC-5 sample showed to be a good candidate for photocatalysis processes due to: (i) its better ordered 1D nanostructure geometry with longer nanotubes after annealing compared to that of the TNTC-7 sample, which conferred an increase of surface area, (ii) due to short length nanotubes, since better efficient light absorption and fast carrier transport is expected, and thus less unwanted recombination losses, (iii) its chemical structure composition of anatase-rutile in comparison to that at 700 °C that transformed completely in rutile, (iv) a clean top surface, (v) the preservation of stable morphology after exposing to corrosive electrolytes in long term showing a high corrosion stability and (vi) its major and stable photocurrent density.

Influence of calcination on photocatalytic properties of nonstoichiometric titanium dioxide nanotubes

The nonstoichiometric titanium dioxide nanotubular films were synthesized by the anodization of titanium foil in a solution of ethylene glycol and ammonium fluoride. The calcination of films at the temperatures of 200–600 °C led to the changes in their morphology, structure, phase composition, and properties. During the calcination, amorphous phase of titanium oxide in the prepared films was converted into anatase (space group I41/amd) at ca. 300 °C followed by the transformation of anatase to rutile (space group P42/mnm) at the temperatures above 500 °C. The optical band gap was decreased as the calcination temperature was increased due to the changes in stoichiometry and phase composition of nanotubular films. A complete mineralization of acetone vapor in a continuous-flow reactor using the nanotubular films was carried out for the first time. The photocatalytic activity of the film calcined at 500 °C in the reaction of acetone oxidation to carbon dioxide under visible light (λmax = 450 nm) was found to be 4 times higher than the activity of commercially available TiO2 P25. A high defectiveness and an extended surface were the reasons for an enhanced photocatalytic activity of the synthesized nanotubular films under visible light.

Synthesis of TiO2 nanotubular arrays and their electrochemical and photoelectrochemical properties to determine their use in photodegradation processes

The synthesis of TiO2 nanotubular films is presented together with their physical, chemical, electrochemical and photoelectrochemical characterization in order to assess their use as photocatalyst. The synthesis was made through the anodic oxidation procedure using an inorganic fluoride based electrolyte. The nanotubes presented an inner diameter of 54 nm, a wall thickness of 18 nm and a length of 570 nm in amorphous condition. After annealing at 500 °C the alignment and definition of the nanotubes were improved observing more space between the nanotubes, contrary to that observed at 700 °C, in which a detrimental morphology was seen, presenting a disruption of a little portion of the superior edge of the nanotubes. The electrochemical characterization was made for four samples: the amorphous one and two crystallized samples at 500 (TNTC-5) and 700 °C (TNTC-7) and for Ti. The TNTC-5 (constituted by anatase-rutile) which improved its morphology and kept its mechanical strength after annealing, presented the best electrochemical stability after 5 days of exposure. In conclusion, TNTC-5 sample showed to be a good candidate for photocatalysis processes due to: (i) its better ordered 1D nanostructure geometry with longer nanotubes after annealing compared to that of the TNTC-7 sample, which conferred an increase of surface area, (ii) due to short length nanotubes, since better efficient light absorption and fast carrier transport is expected, and thus less unwanted recombination losses, (iii) its chemical structure composition of anatase-rutile in comparison to that at 700 °C that transformed completely in rutile, (iv) a clean top surface, (v) the preservation of stable morphology after exposing to corrosive electrolytes in long term showing a high corrosion stability and (vi) its major and stable photocurrent density.

Formation of Nanotubular Films Based on Anodization of Ti and Ti Alloys

Formation of Nanotubular Films Based on Anodization of Ti and Ti Alloys

Nonstoichiometric titanium dioxide nanotubes with enhanced catalytical activity under visible light

The catalytic activity of nanotubular titanium dioxide films formed during the oxidation of acetone to carbon dioxide under the action of visible light with a wavelength of 450 nm was found to be approximately 2 times higher compared to standard titanium dioxide (Degussa P25). The nanotubular films were grown by the anodization of titanium foil using an original technique. Diffuse reflectance spectra of the films are attributed to enhanced activity in the visible spectrum by the nonstoichiometry of titanium dioxide near the interface between the nanotubular film and the titanium foil substrate.

Oriented Multiwalled Organic–Co(OH)2 Nanotubes for Energy Storage

AbstractIn energy storage materials, large surface areas and oriented structures are key architecture design features for improving performance through enhanced electrolyte access and efficient electron conduction pathways. Layered hydroxides provide a tunable materials platform with opportunities for achieving such nanostructures via bottom‐up syntheses. These nanostructures, however, can degrade in the presence of the alkaline electrolytes required for their redox‐based energy storage. A layered Co(OH)2–organic hybrid material that forms a hierarchical structure consisting of micrometer‐long, 30 nm diameter tubes with concentric curved layers of Co(OH)2 and 1‐pyrenebutyric acid is reported. The nanotubular structure offers high surface area as well as macroscopic orientation perpendicular to the substrate for efficient electron transfer. Using a comparison with flat films of the same composition, it is demonstrated that the superior performance of the nanotubular films is the result of a large accessible surface area for redox activity. It is found that the organic molecules used to template nanotubular growth also impart stability to the hybrid when present in the alkaline environments necessary for redox function.

Electrochemical Characterization of TiO2 Nanotubular Films Exposed in an Aqueous Solution with a pH = 3.2

ABSTRACTTiO2 nanotubular structures were fabricated on Ti polished and unpolished foils exposed to H2O-Glycerol (50-50Vol.%)+0.27 M NH4F at 20V. The obtained TiO2 nanostructures were analyzed by SEM obtaining the morphological characterization, from which the roughness factors were calculated. Crystalline phases of both TiO2 nanotubular films were obtained by XRD after annealing at 450 °C and 600 °C for 2 h. The electrochemical stability of the TiO2 nanotubular films was obtained from the potentiodynamic polarization curves (PC) and the linear polarization resistance (Lpr) techniques, exposing the samples in 1M Na2SO4 + H2SO4 solution (pH = 3.2), such pH is in accordance with the acidic wastewater containing sulfur compounds coming from the industries or acid waters of the aquifers, which have been contaminated from the volcanoes nearby. It was concluded that the electrochemical stability of the crystallized nanotubular films is improved with the increase of the annealing temperature of the amorphous TiO2 arrays, which is associated to the higher composition of anatase and rutile, observing that the major amount of rutile improved the corrosion performance. The photoelectrochemical measurements were carried out in 0.5 M Na2SO4 solution using an 8 W UV lamp at a λ= 365 nm, whose results were recorded at zero bias during 10 min under darkness and illumination intervals of 1 min each. The obtained results were in agreement with the necessary features for being used in photocatalytic water remediation.

TiO2 nanotubular films obtained in mixed organic-inorganic electrolyte and their photoelectrochemical and photocatalytic behavior

ABSTRACTTiO2 nanotubular structures were formed on titanium foils through anodic oxidation using an electrolyte of Ethyleneglycol-H2O (97:3 Vol %)+0.25 M NH4F at a constant voltage of 60V. The anodized samples were analyzed in a FE-SEM obtaining the geometric parameters of the nanotubular arrays. The diameter and the length of the nanotubes were 112 nm and 65µm |respectively, whereas the wall thickness was 44 nm. Crystalline phase of TiO2 nanotubular films (TNTF) were determined by XRD after annealing at 500°C for 2 h, resulting high intensity peaks of anatase and low intensity peaks of rutile. Then, the crystallized samples were characterized from an optical, photoelectrochemical and photocatalytic point of view. The photoelectrochemical measurements were carried out in 0.5 M Na2SO4 solution using an 8 W UV lamp at a λ= 365 nm, which results were recorded at 0 bias during 10 min under darkness and illumination intervals of 1 min each. Photocatalytic performance of the TNTF was explored with a 10 mg/L methyl orange solution using an UV light at a wavelength of 365 nm. The changes in the concentration of the MO solution was determined from the calibration curve determined from the absorption spectra at different concentrations of MO (from 0.1 mg/L to 20 mg/L). It was observed an efficiency yield of 99.8% in the photocatalytic performance in presence of the TNTF.

A first insight on the bio-functionalization mechanisms of TiO2 nanotubes with calcium, phosphorous and zinc by reverse polarization anodization

The decoration of titanium (Ti) implant surfaces with TiO2 nanotubes has emerged as a promising strategy to improve osseointegration and avoid infection. Nevertheless, it has been reported that nanotubular films are prone to peeling off from the Ti substrate due to the poor interfacial adhesion. The knowledge on the interfacial properties of such interface, although not well explored, is crucial for understanding the mechanisms behind the poor adhesion problem of these films and to further achieve an easy and effective solution to solve it.This paper is focused on the bio-functionalization of TiO2 nanotubular films with zinc (Zn) as an antimicrobial and bone healing agent, together with two major components of bone matrix, namely calcium (Ca) and phosphorous (P). The main aim is, for the first time, the thorough characterization of the interface between TiO2 nanotubes and the Ti substrate, along with the better understanding of the bio-functionalization mechanisms of TiO2 nanotubes and their influence on the interfacial features of the films.TiO2 nanotubes were successfully synthesized by two-step anodization and their bio-functionalization with Ca, P and Zn was achieved by reverse polarization anodization treatments. The in-depth characterization of the morphological and chemical features of TiO2 nanotubes was carried out along their length by scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDS), before and after bio-functionalization treatments. STEM images showed that the interface between conventional TiO2 nanotubes and Ti is non-continuous due to the existence of a hollow space. However, bio-functionalized TiO2 nanotubes evidenced an interface with different features, due to the formation of an interfacial oxide film as a consequence of anodization, with a thickness comprised between 230 and 250nm.The results presented in this work may inspire the emergence of novel surface treatment strategies seeking the long-term performance of metallic-modified osseointegrated implants.

Tribo-electrochemical behavior of bio-functionalized TiO2 nanotubes in artificial saliva: Understanding of degradation mechanisms

It has been shown that the synthesis of TiO2 nanotubes by anodization provides outstanding properties to Ti surfaces intended for dental and orthopedic implants applications. Beyond the very well-known potential of these surfaces to improve osseointegration and avoid infection, the knowledge on the adhesion and degradation behavior of TiO2 nanotubes under the simultaneous action of wear and corrosion is still poorly understood and these are issues of tremendous importance. The main aim of this work is to investigate, for the first time, the tribo-electrochemical degradation behavior of Ti surfaces decorated with TiO2 nanotubes before and after bio-functionalization treatments.Well-aligned TiO2 nanotubes (NTs) were produced containing elements natively present in bone such as calcium (Ca) and phosphorous (P), in addition of zinc (Zn) as an antimicrobial agent and stimulator of bone formation. The synthesis of Ca/P/Zn-doped nanotubes (NT-Ca/P/Zn) was achieved by reverse polarization and anodization treatments applied to conventional TiO2 nanotubes grown by two-step anodization. The nanotube surfaces were analyzed by scanning electron microscopy (SEM) while dark-field scanning transmission electron microscopy (STEM-DF) was used to characterize the Ti/TiO2 nanotubular films interfaces. Tribo-electrochemical tests were conducted under reciprocating sliding conditions in artificial saliva. The open circuit potential (OCP) was monitored before, during and after sliding tests, and the coefficient of friction (COF) values were registered during rubbing action. The wear tracks resulting from sliding tests were characterized by SEM and wear volume measurements were carried out by 2D profilometry.The results show that the tribo-electrochemical behavior of TiO2 nanotubes was significantly improved after bio-functionalization treatments. The higher electrochemical stability and lower mechanical degradation of these films was correlated with their improved adhesion strength to Ti substrate, which is granted by the nano-thick oxide film formed at the interface region, during bio-functionalization processes. A first insight on the degradation mechanisms taking place during tribo-electrochemical action is proposed. The outcomes of this study may contribute in a great extent for the development of new implant surfaces with improved biomechanical stability and thus contribute for the long term success of dental implants.

Investigation of the mechanical and chemical characteristics of nanotubular and nano-pitted anodic films on grade 2 titanium dental implant materials

ObjectiveThe objective of this study was to investigate the reproducibility, mechanical integrity, surface characteristics and corrosion behavior of nanotubular (NT) titanium oxide arrays in comparison with a novel nano-pitted (NP) anodic film. MethodsSurface treatment processes were developed to grow homogenous NT and NP anodic films on the surface of grade 2 titanium discs and dental implants. The effect of process parameters on the surface characteristics and reproducibility of the anodic films was investigated and optimized. The mechanical integrity of the NT and NP anodic films were investigated by scanning electron microscopy, surface roughness measurement, scratch resistance and screwing tests, while the chemical and physicochemical properties were investigated in corrosion tests, contact angle measurement and X-ray photoelectron spectroscopy (XPS). Results and discussionThe growth of NT anodic films was highly affected by process parameters, especially by temperature, and they were apt to corrosion and exfoliation. In contrast, the anodic growth of NP film showed high reproducibility even on the surface of 3-dimensional screw dental implants and they did not show signs of corrosion and exfoliation. The underlying reason of the difference in the tendency for exfoliation of the NT and NP anodic films is unclear; however the XPS analysis revealed fluorine dopants in a magnitude larger concentration on NT anodic film than on NP surface, which was identified as a possible causative. Concerning other surface characteristics that are supposed to affect the biological behavior of titanium implants, surface roughness values were found to be similar, whereas considerable differences were revealed in the wettability of the NT and NP anodic films. ConclusionOur findings suggest that the applicability of NT anodic films on the surface of titanium bone implants may be limited because of mechanical considerations. In contrast, it is worth to consider the applicability of nano-pitted anodic films over nanotubular arrays for the enhancement of the biological properties of titanium implants.