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Objective: The aim of this in vitro study was to evaluate the effect of an oxide nanocoating to prevent colour degradation of maxillofacial silicone elastomers following accelerated ageing. Material and methods: Specimens (N = 40) of specified dimensions were fabricated in Factor II room temperature vulcanizing (RTV) silicone and processed according to the manufacturer's instructions. Two groups were classified with 20 specimens each. Specimens in the first group were coated with titanium dioxide (TiO2) by atomic layer deposition technology. The colour stability test was conducted with a UV–VIS spectrometer (Schimadzu) for both titanium dioxide nanocoated and uncoated specimen groups after subjecting them to accelerated ageing. It was analysed using the CIE L*a*b method. Results: The average colour change was highest for uncoated specimens (2.868), and the average colour change for titanium dioxide-coated specimens was significantly low (1.774). The average colour change of uncoated specimens (2.868) was close to the acceptable threshold value (3), and that of coated specimens (1.774) was far below the acceptable threshold (3). Conclusions: The colour change that occurred in titanium dioxide nanocoated specimens following accelerated ageing was significantly lower than that in the uncoated group, showing that the TiO2 nanocoating was effective in reducing the colour degradation of silicone elastomers. Clinical relevance: Maxillofacial prostheses fabricated from silicone elastomers go through undesirable colour degradation over time. The development of a scientific technique that retards the colour deterioration of silicone prostheses would be of great clinical significance. [ABSTRACT FROM AUTHOR]

Acacia mangium requires the addition of a finishing material to increase its resistance to weathering. Herein, the effectiveness of a nanocoating containing titanium dioxide nanoparticles (TiO2-NPs) as a finishing material for mangium wood was investigated. The coating material formulations used were oil-based (V1) and water-based (V2) varnishes with TiO2-NP concentrations of 1% (CT1), 5% (CT5), and 10% (CT10) (w/v). The uncoated and coated samples were subjected to weathering periods of 0, 2, and 4 months. The results showed that the addition of TiO2 nanoparticles to the V1 and V2 varnishes resulted in more gradual colour changes after the weathering period. The surface of the mangium wood also became smoother after being coated. However, the surface roughness increased with the duration of the weathering period. The wettability (K-value) of the sample decreased after coating, indicating that the coated sample was more hydrophobic than the uncoated sample. The results of a photocatalyst test, which analysed the effectiveness of the coatings, showed that the best coating material formulas were V1-CT10 and V2-CT10, as they degraded 75.21% and 71.03% of methylene blue content, respectively. Fourier transform infrared analysis showed that mangium wood did not undergo rapid weathering after the nanocoating treatment, as indicated by an insignificant decrease in the peak absorption intensity of the main structural functional groups of wood. [ABSTRACT FROM AUTHOR]

This comprehensive review examines the current state of self-cleaning nanocoatings for building surfaces. Nanocoatings are a form of nano-structured materials that contain active components, such as photocatalysts, that provide superior self-cleaning properties when exposed to light. This review discusses the various materials and methods used in the development of selfcleaning nanocoatings, including titanium dioxide, zinc oxide, and other metal oxide. The properties of these materials, such as photocatalytic activity, durability, and water repellency are described in detail. The review also provides a comprehensive overview of the preparation methods for nanocoatings, including physical vapor deposition, chemical vapor deposition, and sol-gel processing. Finally, the review concludes with a discussion of the potential applications of self-cleaning nanocoatings for building surfaces, such as reducing maintenance costs, improving aesthetics, and increasing energy efficiency. [ABSTRACT FROM AUTHOR]

In this study, we developed novel bionanocomposites consisting of chitosan (CS), poly (vinyl alcohol) (PVA), trans -cinnamaldehyde (CIN), and nano-titanium dioxide (TiO 2) using a blending method. The results demonstrated that the addition of TiO 2 and CIN significantly enhanced the films' light transmittance, mechanical, antimicrobial, and antioxidant properties. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) observations revealed that the nanocomposite films were dense and intact. We also investigated, the effect of nanocomposite coating on storage of button mushrooms at 4 °C for 10 d. The results indicated that the nanocomposite coating maintained the hardness and total polyphenol content of the mushrooms and inhibited the growth of malondialdehyde and reducing the browning index compared with the control groups. Additionally, the nanocomposite-coated mushrooms exhibited higher 3-octanone, a key flavor compound, than the control, thus preserving post-harvest flavor and texture. This study provides valuable insights into developing effective bionanocomposite coatings to extend the shelf life and maintain the quality of postharvest fruits and vegetables. [Display omitted] • TiO 2 and CIN greatly enhance the properties of CS/PVA film in various ways. • The bio-nanocomposites improved the antioxidant property and quality of mushroom. • CS/PVA/CIN/TiO2 coating maintained the unique flavor of button mushroom. • CS, PVA, CIN and TiO 2 nanocoating can prolong the shelf life of mushroom. [ABSTRACT FROM AUTHOR]

With increasing urbanization and industrialization there is an upsurge in air pollution that demands immediate attention. The use of nanomaterials to alleviate air pollution is gaining importance. Certain nanomaterials can photocatalytically act on air pollutants such as oxides of nitrogen (N0x), sulfur (SOX), and carbon (CO2), thereby bringing down their concentration locally. Titanium Dioxide (TiO2), its composites, and TiO2 based Z/S scheme heterojunction photocatalysts are a few such nanomaterials. The band-gap of TiO2 in solid-state (3.2 eV) makes it a good photocatalyst in the ultraviolet region and its composites in the visible light region of the spectrum. Metropolitan cities are densely filled with high-rise buildings and the exteriors of these buildings, which are largely exposed to the atmosphere, can be utilized to coat these nano materials to enable photocatalytic reduction of air pollutants in the surrounding atmosphere. The nano photocatalysts can either be applied as coatings on the existing buildings or incorporated into the construction materials during construction. In this review article, an attempt is made to cover the application of photocatalysts in the construction industry starting from the working principle (mechanism) of heterogeneous and heterojunction photocatalysts, their advantages and disadvantages, methods of synthesis, pollution control applications, with emphasis on the methods of incorporating the photocatalysts into construction materials and also as a coating on existing buildings, the set up required to evaluate NOX reduction and the factors that affect the NOX reduction. The current status of pollution control applications in the construction industry and the authors perspective on the application of heterojunction photocatalysts in construction industry are highlighted. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to evaluate the possibility of using titanium dioxide coating in the field of architectural heritage. Design/methodology/approach: In this research, a titanium dioxide coating was prepared and then applied to the travertine stone surfaces. The nature of the coating was determined through various observations and analyses. Moreover, the effect of photocatalytic self-cleaning was evaluated using an organic dye (Rhodamine B). Findings: The results of XRD, DLS and SEM confirmed the formation of small anatase crystals. The hydrophilic behavior on the surface was observed by coatings based on titanium dioxide. Research limitations/implications: The self-cleaning ability of titanium dioxide is due to the synergistic effect of its optical inductive property, which is activated with sunlight. Practical implications: The self-cleaning coatings are interested for many industries. The reported data can be used by the formulators working in the research and development departments. Social implications: Self-cleaning systems are considered as smart coatings. Therefore, the developing of its knowledge can help to extend its usage to different applications. Originality/value: The application of titanium dioxide coating in the field of architectural heritage is a great challenge. Therefore, in this research, a titanium dioxide coating was prepared by sol-gel method and then applied on travertine surfaces and its properties were studied. [ABSTRACT FROM AUTHOR]

Existing industrial titania production lines and their intermediate products are economically attractive precursors for synthesis of highly concentrated TiO2 coating sols and soluble nanopowders. Refluxing of aliphatic alcoholic TiOCl2 solutions (with up to 500 g TiO2/L) allows straightforward formation of nonaggregated anatase nanocrystals with size between 5 and 8 nm. Surface modification of these nanoparticles with organosilanes shifts the pH value of point of zero charge from initially 5.3 down to around 2.8. At appropriate Ti/Si ratios, complete suppression of the anatase ultraviolet (UV) photoactivity is possible. Furthermore, we address the optical and photocatalytic data of transparent nanocrystalline layers produced from superconcentrated ZnxTiyOz heterosols. Depending on the Zn/Ti ratio and processing temperature, colorless cubic c-ZnTiO3 and c-Zn2TiO4 spinel nanophases or coupled r-ZnTiO3-ilmenite/r-TiO2-rutile heterojunctions (Zn/Ti = 2/3) can be produced. The cubic spinel films are indirect semiconductors showing band gap transition of around 3.7 eV. In contrast, r-ZnTiO3-ilmenite films have slightly lower band gap of around 3.6 eV. Organic dye photodegradation studies reveal the highest catalytic activity for the coupled r-ZnTiO3-ilmenite/r-TiO2-rutile systems compared with colored (nitridated) or colorless cubic spinel film samples. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The need to overcome the failure of orthodontic micro-implants which might reach to 30% has led to the development of different methods, one of which is nanoparticle deposition. AIM OF STUDY: To evaluate the anti-microbial efficiency of TiO2 and ZnO nanoparticles (NP) when used as a coating for orthodontic micro-implants. METHODS: Thirty titanium alloy micro-implants were used in the presented study. They were divided into three groups according to the coating method and the coating materials used: the control group without surface coating; the titanium dioxide (TiO2)-coated group, in which direct current (DC) spattering was used to coat the micro-implants with a TiO2 layer; and the TiO2 and zinc oxide (TiO2ZnO)-coated group, in which the micro-implants were coated with a TiO2 layer via direct current (DC) spattering and a zinc oxide (ZnO) layer via laser vacuum. The micro-implant surfaces were characterized using scanning electron microscopy (SEM) and an energy-dispersive spectrometer (EDS). The antibacterial susceptibility was assessed using gram-positive and gram-negative bacteria. RESULTS: SEM and EDS tests confirmed the coating of the micro-implants in the TiO2- and TiO2ZnO-coated groups. The micro-implants in the TiO2- and TiO2ZnO-coated groups demonstrated higher antibacterial ability than the control group. CONCLUSION: This study demonstrated the significance of improving the surface of orthodontic micro-implants by coating them with TiO2 and ZnO nanoparticles to improve osseointegration and prevent biofilm formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Continuous nano-TiO 2 coating was in situ deposited onto PTFE membrane. • The TiO 2 deposition was bridged by an intermediate layer PFSS. • Oil/water separation efficiency was 99.3% with a permeance of 18,700 LMH/bar. • The TiO 2 /PTFE membrane was stable with high resistance to strong acid and alkali. Treating oily wastewater is of great importance and urgency worldwide. The superhydrophilic and underwater superoleophobic (SUS) membrane is an effective alternative to realize such a goal. However, most SUS membranes are vulnerable in harsh environments, such as strong acidic/alkaline solutions or physical abrasion, resulting in a limited lifespan. In this work, a robust SUS membrane was developed by depositing in situ a TiO 2 nanocoating onto the polytetrafluoroethylene (PTFE) porous membrane with (3-[(perfluorohexyl sulfonyl) amino] propyltriethoxy silane) (PFSS) as an intermediate layer. In the preparation process, the fibrils and nodes of the PTFE membrane were integrally enclosed with the chemical networks generated by hydrolysis and self-condensation of the PFSS. Then, the nano-TiO 2 was in situ bonded with the sulfonyl amide group of the PFSS via bidentate coordination. As a result, an ultrathin and continuous nano-TiO 2 coating (∼20 nm) was created, and the coating covered throughout the porous PTFE matrix. The resultant PTFE membranes demonstrated typical SUS characteristics, while their pore structure was almost unchanged. The PTFE SUS membranes exhibited a high emulsion permeance (up to 18,700 L m–2h−1 bar−1) with a separation efficiency above 99.3%. Attributed to the soldering effect of the PFSS between TiO 2 nanoparticles and the PTFE membrane, the developed SUS membranes exhibited excellent stability against strong acid/alkali washing and hydraulic shearing, all of which outperformed the majority of current SUS membranes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Preparation of superhydrophobic coatings on carbon steel by one-step method. • Using TiO 2 nanofluids instead of lubricating oil to reduce oil phase leaching. • Stable coating with long-term anti-corrosion. Marine corrosion has been a global problem with the damage on environment, and economy. With the development, traditional coating technology is difficult to meet the current demands of applications. In this study, TiO 2 nanoparticles were modified and dispersed in silicone oil to form TiO 2 nanofluid. And, the nanofluid was infused into hierarchical structure to produce the SLIPS which is obtained by spraying with the solution of Al 2 O 3 , which significantly reduce the lubricant leaching. As synthesized coating shows the good performance in corrosion resistance. The coating prepared by this novel method show the great potential applications in different marine environments. [ABSTRACT FROM AUTHOR]

Our whole-cell biocatalyst with a polydopamine nanocoating shows high catalytic activity (5 times better productivity than the native cell) and reusability (84% of the initial yield after 5 batches, 8 times higher than the native cell) in asymmetric reduction. It also integrates with titania, silica, and magnetic nanoparticles for multi-functionalization. [ABSTRACT FROM AUTHOR]

TiO 2 -based nanocoatings have been applied in practice application of solar cell devices, windows, optical devices, etc., due to their excellent photocatalytic self-cleaning property. However, due to high refractive index of TiO 2 , it is still a challenge to balance the transmittance, photocatalytic and robust properties of TiO 2 -based nanocoatings. In this work, we successfully fabricated SiO 2 @TiO 2 composite nanocoating with mechanical robustness, antireflection (enhanced transmittance) and photocatalytic self-cleaning properties by introducing commercial Degussa P25-type titania nanoparticles (P25) into the system of small solid silica nanoparticles (SSNs) as a building block and acid-catalyzed silica sol (ACSS) as a crosslinking agent, via a simple dip-coating strategy without any post-treatment. The weight ratios of SSNs to P25 were tuned to realize the balance of optical and photocatalytic properties. The optimized nanocoating exhibits a maximum transmittance of ca. 96.5 % at the wavelength of 552 nm, minimum reflectivity of ca. 1.6 % at the wavelength of ca. 600 nm, good hydrophilicity (14.2° of WCAs), high photocatalytic activity of degrading the pollutants, and high mechanical robustness of 3 H pencil hardness test and 5 A tape adhesion test. This work provides a simple and feasible design idea for low-cost and facile fabrication of robust anti-reflection self-cleaning nanocoating. [Display omitted] • Cheap commercial P25-type TiO 2 nanoparticles was introduced into small SiO 2 nanoparticles and acid-catalyzed SiO 2 sol. • The weight ratios of SSNs to P25 were tuned to realize the balance of optical and photocatalytic properties. • Simple dip-coating, low cost and no post-treatment facilitated potential practice application • Robust SiO 2 @TiO 2 nanocoatings with antireflection and photocatalytic self-cleaning properties were fabricated. [ABSTRACT FROM AUTHOR]

From the advent of nanotechnologies in building constructions, many materials were functionalized to create composite material with new properties. Titania (TiO 2 ) is actually the most promising nanotechnology to create composite materials with self-cleaning and anti-microbial properties. TiO 2 was able to limit algae adhesion and their growth, even if, in case of high porous and rough substrata, their inhibitory effect seems to be limited. This way, in this study, silver and copper nano-particulate enhanced an aqueous nano-titania solution were applied on brick specimens and their inhibitory effects were tested during accelerated laboratory tests. Extent of biofouling on specimens’ surface was assessed by measuring the aesthetical alteration and correlations between algal growth and key parameters of substrata were discussed. Results confirm the key role of porosity and roughness on the biofouling process on untreated specimens, and their effect on the photocatalytic power of the tested nano-coatings toward algal adhesion. Results from this study were compared with previous findings in the literature on the same types of specimens only treated with the same aqueous nano-titania solution. No significant improvements were detected by the addition of metal nanoparticles. Experimental curves were overlapped to analytical model calculated by Avrami’s law, and its validity was confirmed where latency time could be observed. Whereas no latency time was detected, that is a very fast adhesion of algal cells occurred, the experimental curves were modelled by using a four parametric logistic model that was able to describe numerically the biofouling process. [ABSTRACT FROM AUTHOR]

Although the superhydrophobicity and transparence are generally two contradictory characters as the roughness factor, it is literature abundant for achieving both of these two purposes. To our knowledge, the integration multipurpose (transparent, superhydrophobic, superhydrophilic, underwater superoleophobicity, anti-fogging, and photo-controllable ability) in one has not been reported so far and these are vital for their promising applications in various aspects which can attract broad attention from scholars to engineers. In this work, we are successful to bio-inspired design of a kind versatile transparent nanocoating with superhydrophobic or superhydrophilic/underwater superoleophobic properties. The TiO/SiO nanocoatings can be transformed from superhydrophobicity into superhydrophilicity and underwater superoleophobicity after heat treatment (450 °C and 2 h). If it was coated on conductive glass, the electrical conductivity was impervious, while the wettability can be manipulated. Importantly, both these superhydrophobic and superhydrophilic TiO/SiO composite nanocoatings were endowed with photo-induced self-cleaning nature and these antifouling coatings could prolong their service life. [ABSTRACT FROM AUTHOR]

A new photocatalyst of sodium humate (HA-Na)/Nano-TiO2 coating on the glass spheres for flue gas denitrification (DeNO x) was prepared using the impregnation method. The HA-Na/TiO2 is characterized by Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The photocatalytic activity of HA-Na/TiO2 on removing NO x was investigated in a self-designed photocatalytic reactor. The synergistic mechanism of HA-Na and TiO2 on DeNO x is also proposed and demonstrated. The experimental results indicate that specific surface area and average pore size of HA-Na are improved owing to the mixed TiO2 nanoparticles. The crystal structure of TiO2 has little change after mixing with HA-Na. Due to high photocatalytic performance of TiO2, NO was oxidized to NO2 and HNO3 eventually. On the other hand, HA-Na support can absorb and react with HNO3, which accelerates 10% of the catalytic reaction of TiO2 and the utilization of light source. The chemical and physiological activity of oxidized HA-Na are improved than the original humate. The HA-Na/TiO2 photocatalysts show great property on eliminating NO x because of the promoting effect between HA-Na and TiO2, and the NO removal efficiency can reach to 80% at the optimum condition. A new photocatalyst of HA-Na/TiO2 coating on the glass spheres for flue gas denitrification was prepared. There is a synergistic reaction mechanism between the TiO2 and HA-Na on DeNO x. TiO2 nanoparticles may improve HA-Na in the specific surface area, pore structure, and catalytic oxidation of NO. The NO removal efficiency of TiO2 is increased by 10% with HA-Na, indicating that HA-Na plays a key role in decreasing NO emission in this photocatalystic process. [ABSTRACT FROM AUTHOR]

TiO 2 is a promising photocatalyst for use in food processing environment as an antimicrobial coating. The purpose of this study was to determine the effect of different binding agents on the physical stability and bactericidal property of TiO 2 nanocoatings created on stainless steel surfaces. A total of six different coating suspensions were prepared by mixing TiO 2 (Aeroxide ® P-25) nanoparticles (NPs) with three different types of binders (Shellac (A), polyuretahne (B), and polycrylic (C)) at a 1:4 to 1:16 NP to binder weight ratio. Bactericidal activity of these TiO 2 coatings against Escherichia coli O157:H7 (5-strain) was determined at three different UV-A light intensities (0.25, 0.50 and 0.75 mW/cm 2 ) for 3 h. The type of binder used in the coating had a significant effect on the log reduction of E . coli O157:H7. TiO 2 coatings with binder C showed highest reduction (>4 log CFU/cm 2 ) followed by TiO 2 coating with binder B and A. Increasing the binder concentration in the formulation from a 1:4 to 1:16 weight ratio decreased the log reduction of E . coli O157:H7. Increasing the UV-A light intensity from 0.25 to 0.75 mW/cm 2 increased the log reduction of bacteria for all the TiO 2 coatings. The physical stability of the TiO 2 coatings was determined using ASTM procedures. TiO 2 coatings with binder B showed highest adhesion strength and scratch hardness when compared to coatings with other binders. However, on repeated use experiments (1, 3, 5, and 10 times), TiO 2 coatings with binder C were found to be physically more stable and able to retain their original bactericidal property. The results of this study showed promise in developing durable TiO 2 coatings with strong photocatalytic bactericidal property on food contact surfaces using appropriate binding agents to help ensure safe food processing environment. [ABSTRACT FROM AUTHOR]

Purpose: Titanium dioxide nanoparticles (TiO2-NPs) have been widely developed for versatile use, but the potential risk form their skin exposure is still unclear. To evaluate this risk, the skin penetration of TiO2-NPs is necessary to be understood first. The aims of this study are to investigated the penetration of TiO2-NPs through slightly damaged skin and intact skin in vitro and in vivo. Methods: TiO2-NPs with a diameter of 20 nm was labeled with 125I.The skin of rat was treated with 2% SLS solution and obtained as slightly damaged skin. The 125I labeled TiO2-NPs (125I-TiO2-NPs)solution and 0.9% PS solution were added into the donor chamber and receptor chamber of static diffusion cells which clamped the skin at the middle of two half-cells, respectively. During 24 hours, samples were extracted from the receptor chamber and counted for 1 min using γ-counter to detect the radioactivity. The skin penetration of TiO2-NPs in vitro was expressed as the percentage of radioactivity of receptor chamber solution compared with total radioactivity in the donor chamber. Thereafter, the 125I-TiO2-NPs was exposed to the rats. After 1 day and 3 days, the blood and tissues of rats were harvested, weighed and counted for 1 min using γ-counter to detect the tissue radioactivity. The skin penetration of TiO2-NPs in vivo was expressed as the percentage dose per gram tissue (% dose/g). Results: In the skin penetration experiment in vitro, the radioactivity of receptor chamber solution through damaged skin was higher than that of through intact skin and was about 2% radioactivity of donor chamber on 24 h. In the skin penetration experiment in vivo, the radioactivity of blood and tissues of rats after exposing to 125I-TiO2-NPs solution though damaged skin or intact skin were less than 0.05% dose/g on 1 d and quickly declined on 3 d. The skin penetration rates of TiO2-NPs through slightly damaged skin and intact skin in vitro and vivo were lower than the rate of free 125I in the TiO2-NPs solution. Conclusions: The TiO2-NPs could not penetrate through the damaged skin or intact skin both in vitro and in vivo. It suggested that the TiO2-NPs should be safe when it was applied and contacted with skin. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) is a well-known photocatalyst for its excellent bactericidal property under UVA light. The purpose of this study was to develop physically stable TiO2 coatings on food contact surfaces using different binding agents and develop methods to evaluate their durability and microbicidal property. Several types of organic and inorganic binders such as polyvinyl alcohol, polyethylene glycol, polyurethane, polycrylic, sodium and potassium silicates, shellac resin, and other commercial binders were used at 1:1 to 1:16 nanoparticle to binder weight ratios to develop a formulation for TiO2 coating on stainless steel surfaces. Among the tested binders, polyurethane, polycrylic, and shellac resin were found to be physically more stable when used in TiO2 coating at 1:4 to 1:16 weight ratio. The physical stability of TiO2 coatings was determined using adhesion strength and scratch hardness tests by following standard ASTM procedures. Further, wear resistance of the coatings was evaluated based on a simulated cleaning procedure used in food processing environments. TiO2 coating with polyurethane at a 1:8 nanoparticle to binder weight ratio showed the highest scratch hardness (1.08 GPa) followed by coating with polycrylic (0.68 GPa) and shellac (0.14 GPa) binders. Three different techniques, namely direct spreading, glass cover-slip, and indented coupon were compared to determine the photocatalytic bactericidal property of TiO2 coatings against Escherichia coli 0157:H7 at 2 mW/cm2 UVA light intensity. Under the tested conditions, the indented coupon technique was found to be the most appropriate method to determine the bactericidal property of TiO2 coatings and showed a reduction of 3.5 log CFU/cm2 in 2 h. [ABSTRACT FROM AUTHOR]

Titanium dioxide has been recently used in its nanometric form to develop smart products and coatings on several building components so as to better preserve their visual aspect, mainly by way of its very efficient photocatalytic function. The integration of further nanostructured materials with titanium dioxide may enhance its features or add new properties to these products. The aim of this review is to provide a report on the latest developments in a specific area of the maintenance of architectural surfaces: the use of multifunctional (self-cleaning, de-polluting, biocidal) nanocoatings based on titanium dioxide on architectural stone surfaces. The results of several studies concerning different products containing TiO 2 nanoparticles, potentially added with other nanometric elements, have been summarised and compared from several points of view focused on their compatibility with treated substrates and their effectiveness against diverse degrading agents (soil, pollution and microorganisms). From the discussed works, the application of TiO 2 -based products on several architectural stones seems to be feasible and valuable; however several features are in need of deeper analyses before real large-scale use. In addition, possible future developments by scientific research may provide further increased performances and additional features and functions to these treatments. [ABSTRACT FROM AUTHOR]

We proposed the application of titanium dioxide (TiO2) for the preservation of historical (architectural, monumental, archaeological) stone surfaces. Solar light can activate the photocatalytic effect of TiO2 nanoparticles: heterogeneous photocatalysis is the key factor for the development of self-cleaning, depolluting and biocidal treatments able to photochemically degrade external damaging materials and prolong the durability of treated substrates, maintaining their original aspect and limiting ordinary cleaning activities. In this study, TiO2 nanoparticles dispersed in an aqueous colloidal suspension were applied directly on travertine, a light-colored limestone, by spray-coating in order to obtain a nanometric film on stone samples. To assess the feasibility of use of TiO2, we studied the characteristics of the nanocoating-stone system by monitoring the microscopic features of the coatings, the aesthetical changes induced to coated surfaces and the self-cleaning efficiency. We also monitored the self-cleaning ability over time during an accelerated ageing process to evaluate the durability of TiO2-based treatments. We confirmed both compatibility and effectiveness of TiO2 coating in the short term, anyway its efficiency decreased after artificial ageing. Further studies are necessary to better evaluate and eventually improve the stability of self-cleaning efficiency over prolonged time for outdoor stone surfaces. [ABSTRACT FROM AUTHOR]

This article describes a photocatalytic nanostructured anatase coating deposited by cold gas spray (CGS) supported on titanium sub-oxide (TiO) coatings obtained by atmospheric plasma spray (APS) onto stainless steel cylinders. The photocatalytic coating was homogeneous and preserved the composition and nanostructure of the starting powder. The inner titanium sub-oxide coating favored the deposition of anatase particles in the solid state. Agglomerated nano-TiO particles fragmented when impacting onto the hard surface of the APS TiO bond coat. The rough surface provided by APS provided an ideal scenario for entrapping the nanostructured particles, which may be adhered onto the bond coat due to chemical bonding; a possible bonding mechanism is described. Photocatalytic experiments showed that CGS nano-TiO coating was active for photodegrading phenol and formic acid under aqueous conditions. The results were similar to the performance obtained by competitor technologies and materials such as dip-coating P25 photocatalysts. Disparity in the final performance of the photoactive materials may have been caused by differences in grain size and the crystalline composition of titanium dioxide. [ABSTRACT FROM AUTHOR]

Highlights: [•] TiO2-coated LTO was in-situ prepared via a microemulsion-assisted hydrothermal route. [•] Anatase-TiO2 coating layer enhances the electrochemical performance of Li4Ti5O12. [•] The as-prepared sample presents high-rate capability and cyclic stability. [Copyright &y& Elsevier]

Highlights: [•] Permanent superhydrophobic properties on injection-molded polypropylene substrates can be obtained by a simple dip-nanocoating process. [•] At Ti–OH surface relative concentrations higher than about 25%, the surface kept a superhydrophobic static state but lost its self-cleaning properties. [•] Precise tuning on the superhydrophobic dynamic component can be obtained by the control of the roughness together with the chemical surface composition of polar groups. [ABSTRACT FROM AUTHOR]

Highlights: [•] Direct ceramization of textile substrates with commercial derived TiO2 nanosols. [•] Five nanosols, differing for starting pH and relative aggregates size. [•] Correlations between physico-chemical nano-macro scale properties and performances. [•] Industrially scalable application. [•] Inputs for the control of material performance by design experiments. [Copyright &y& Elsevier]

Abstract: Microalgal growth largely affects the aesthetical properties of building façades worldwide. It causes biodeterioration of building materials and, in a later stage, it can compromise integrity of the elements and their durability. Recently, the use of nanotechnology to prevent the growth of microalgae is rising. One of the most widespread and promising material is titanium dioxide (TiO2). Photocatalytic properties of TiO2 inhibit biofouling of microalgae when this coating is stimulated by UV radiation coming from the sun or from artificial light. In this study, the biocide effect of TiO2 coatings applied on clay brick specimens under weak UV radiation was assessed. Results revealed that TiO2 nanocoating was not able to fully prevent microalgal biofouling, but under optimal UV exposure conditions for the growth of microalgae it efficaciously prevented the adhesion of these microorganisms on the treated substrates through the formation of a superficial water film. This property resulted in a good self-cleaning efficiency of TiO2. [Copyright &y& Elsevier]

Attempts have been made to improve the performance of dye-sensitized solar cells by forming metal-oxide nanocoating layers on ZnO electrodes by a sol-gel transformation. SiO2, Nb2O5, TiO2, or ZrO2 nanocoating layers could be formed by dipping ZnO films into metal alkoxide solutions of low concentrations and subsequent heat treatments. The performance of DSSCs using the coated ZnO electrodes depends strongly on the structure of coating layers such as the thickness and the surface coverage, which are significantly influenced by the coating conditions. In particular, SiO2 and Nb2O5 coating layers are effective to suppress the recombination by constructing the energy barrier at the ZnO/electrolyte interface and enhance energy conversion efficiency. It is found that the coating layers also hinder the grain growth of ZnO, contributing to the enhanced cell performance as well. [ABSTRACT FROM AUTHOR]

The UV protective coatings were developed by incorporating triazine derivative organic UV stabilizers into inorganic titania particles which were produced by sol-gel method. The objective of this study is to delay the color change of heat-treated wood subjected to outdoor conditions. The protective coatings were prepared in air at room temperature. The coatings were not further treated thermally after their application to heat-sensitive materials. Coatings were applied to heat-treated jack pine wood. Subsequently, accelerated aging tests were carried out using coated and uncoated jack pine samples. The color change of the wood samples was studied, and the results were compared. Also, the morphological analyses were done using XPS after having weathered the wood at different times. [ABSTRACT FROM AUTHOR]

We describe the use of benzyl alcohols in a solvothermal/alcoholysis reaction to form nanocrystalline sheets of anatase titania. By tuning the reaction conditions, we adjust the size of the nanosheets. The type and density of benzyl groups that decorate the basal plane of the titania sheets control the self-assembly into layered structures. These layered materials can be grown from solid substrates to create iridescent thin films that reflect specific wavelengths of visible light. [ABSTRACT FROM AUTHOR]

Graphite felt (GF) is a multi-functional material and is widely used as electrodes of electrochemical devices for energy and environmental applications. However, due to the inherent hydrophobicity of graphite felt, it must be hydrophilically pretreated to obtain good electrochemical activity. Metal oxides coating is one of the feasible methods to modify the surface of GF, and in order to ensure that the metal oxides have a better conductivity for obtaining higher electrochemical activity, a subsequent H2 heat-treatment process is usually adopted. In this study, atomic layer deposition (ALD) is used to deposit TiO2 nanocoating on graphite felt (GF) for surface modification without any H2 thermal post-treatment. The results show that the ALD-TiO2-modified GF (ALD-TiO2/GF) owns excellent hydrophilicity. Moreover, the ALD-TiO2/GF exhibits excellent electrochemical properties of low equivalent series resistance (Rs), low charge-transfer resistance (Rct), and high electrochemical activity. It demonstrates that ALD is an applicable technique for modifying the GF surface. In addition, it can be reasonably imagined that not only TiO2 film can effectively modify the GF surface, but also other metal oxides grown by ALD with nanoscale-thickness can also obtain the same benefits. We anticipate this work to be a starting point for modifying GF surface by using ALD with metal oxides nanocoating. [ABSTRACT FROM AUTHOR]

The last twenty years have been a period of intense investigations of materials based on titanium dioxide, which have unique properties and functionalities, and which can be used in various areas of medicine. As a part of this issue, the results of our works for the assessment of the photocatalytic activity of titanium dioxide nanocoatings of different nanoarchitecture (nanoporous, nanotubular, nanosponge-like and nanofibrous examples), which were earlier checked in terms of their biocompatibility and usability for the modification of medical devices' surfaces, are presented. The studied materials were produced on the surface of Ti6Al4V substrates using electrochemical and chemical oxidation methods. The activity of produced titania materials was studied on the base of the methylene blue (MB) degradation effect, in accordance to ISO 10678:2010. In our works, we have focused on the analysis of the correlation between the photocatalytic activity of nanoarchitecturally different TiO2 coatings, their morphology and structure. The obtained results prove that all studied coatings, both amorphous and amorphous containing crystalline domains, revealed photocatalytic activity in the photoinduced degradation of the organic pollution standard. This activity may be an additional advantage of medical device coatings, being adequate for use in sterilization processes applying UVA light. [ABSTRACT FROM AUTHOR]

Objective To determine in vitro the loss of integrity caused on photocatalytic anatase coated implant surfaces by clinical instrumentation through changes in surface topography and loss of functionality. Methods Anatase-coated titanium discs were treated with diamond burs, polishers, plastic and metal hand instruments, air scaler and air flow devices. The pressure exerted through instrumentation was measured online. Surface topography was evaluated through scanning electron microscopy and contact profilometry, surface function through hydrophilization capacity upon UV-A activation. Results Treatment with diamond burs and instruments with metal tips resulted in an increase of roughness. Use of silicone polishers led to smoothening, which was more pronounced on the anatase surface. Plastic instruments, the air abrasive system and rubber cups left the surfaces intact. Functionality was partially lost on surfaces subjected to hand instruments and completely lost upon diamond burs and silicone polishers. Significance The integrity of functional nanocoatings depends on the applied instrumentation. Air flow device, rubber cup with polishing paste and plastic tipped instruments prevent damage on these nanosurfaces and may be preferably used when decontaminating anatase and other nanocoatings in a clinical setting. [ABSTRACT FROM AUTHOR]

A titanium dioxide (TiO2) interconnected porous structure has been fabricated by means of atomic layer deposition of TiO2 onto a reticular sponge template. The obtained freestanding TiO2 with large surface area can be easily taken out of the water to solve a complex separation procedure. A compact and conformal nanocoating was evidenced by morphologic characterization. A phase transition, as well as production of oxygen vacancies with increasing annealing temperature, was detected by x-ray diffraction and x-ray photoelectron spectroscopy, respectively. The photocatalytic experimental results demonstrated that the powder with appropriate annealing treatment possessed excellent photocatalytic ability due to the co-action of high surface area, oxygen vacancies and the optimal crystal structure. [ABSTRACT FROM AUTHOR]

In this paper we report on the photocatalytic behavior in gas phase propane oxidation of well-defined TiO 2 nanoparticle (NP) coatings prepared via Supersonic Cluster Beam Deposition (SCBD) on Si-wafers and quartz substrates. The temperature dependent crystal phase of the coatings was analyzed by Raman spectroscopy, and the morphology by High Resolution-Scanning Electron Microscopy. SCBD deposition in the presence of oxygen enables the in situ synthesis of TiO 2 layers of amorphous NP at room temperature. Adapting the deposition temperature to 500 °C or 650 °C leads to Anatase crystals of variable size ranges, and layers showing significant porosity. At 800 °C mainly Rutile is formed. Post annealing by wafer heating of the amorphous NP prepared at room temperature results in comparable temperature dependent phases and morphologies. Photocatalytic activity in propane oxidation was dependent on the morphology of the samples: the activity decreases as a function of increasing particle size. The presence of water vapor in the propane feed generally increased the activity of the wafer-heated samples, suggesting OH groups are not profoundly present on SCBD synthesized layers. In addition, a remarkable effect of the substrate (Si or Quartz) was observed: strong interaction between Si and TiO 2 is largely detrimental for photocatalytic activity. The consequences of these findings for the application of SCBD to synthesize samples for fundamental (spectroscopic) study of photocatalysis are discussed. [ABSTRACT FROM AUTHOR]

Li4Ti5O12 nanorods coated by anatase-TiO2 is prepared via a microemulsion consisting of cetyltrimethylammonium bromide, cyclohexane, BuOH, and LiOH to which Ti(OBu)4 is added followed by hydrothermal treatment (autoclave, 180 °C) and calcination at 550 °C in air. [ABSTRACT FROM AUTHOR]