Hydrophobic Titanium Research Articles

A platinum-based fast-response pressure-sensitive paint containing hydrophobic titanium dioxide

A platinum-based fast-response pressure-sensitive paint containing hydrophobic titanium dioxide

The impact of electric field on the demulsification efficiency in an electro-coalescence process

In this study, the influence of the electric field and its determining parameters such as voltage, inter-electrode distance and frequency on the demulsification efficiency of a water-in-oil emulsion was studied. The numerical analysis showed that the water droplets trapped onto the hydrophobic titanium dioxide (TiO2) coated electrodes and at 2 mm inter-electrode distance can increase the electric field intensity above 300 kV/m, where droplet rupture takes place. Experimental study showed highest demulsification efficiency of 76% while applying AC voltage of 250 V, frequency of 200 kHz and inter-electrode distance of 4 mm.

UV light enhanced catalytic performance of heteropolyacid-TiO2 systems

A series of catalysts based on TiO2 polymorphs were designed with tungstophosphoric acid H3PW12O40 (HPW), either alone or with addition of Fe2O3. These HPW@Fe2O3@TiO2 nanocomposites showed satisfactory performance in the dehydration of n-butanol at 120 – 200 °C in gas-phase under both the thermocatalytic and the photothermocatalytic conditions. The highest catalytic activity in this reaction was achieved over HPW supported on the home-designed TiO2 (HPW/hp), on hp with the addition of Fe2O3 (HPW/Fe/hp) and on the hydrophobic titanium oxide T805 (HPW/T805). The main product turned out to be cis-butene, apart from trans-butene, di-n-butyl ether (DNBE) and butyraldehyde that have also been detected. The influence of the light on the course of the catalytic alcohol conversion was discussed. Basing on proposed energy diagram with electron and hole transfer paths for the HPW@Fe2O3@TiO2 catalysts the probable mechanism of charge transfer upon UV irradiation was proposed.

High-Speed Erosion Behavior of Hydrophobic Micro/Nanostructured Titanium Surfaces.

Ice accretion on aircrafts or their engines can cause serious problems and even accidents. Traditional anti-icing and de-icing systems reduce engine efficiency, which can be improved by the use of hydrophobic/icephobic coatings or surfaces that reduce the amount of bleed air or electric power needed. These hydrophobic/icephobic coatings or surfaces are eroded by high-speed air flow, water droplets, ice crystals, sand, and volcanic ash, resulting in the degradation, material loss, or deterioration of the coating’s waterproof and anti-icing properties. Thus, the durability of hydrophobic micro/nanostructured surfaces is a major concern in aircraft applications. However, the mechanism responsible for material loss in hydrophobic micro/nanostructured surfaces resulting from high-speed erosion remains unclear. In this paper, hydrophobic titanium alloy surfaces with cubic pit arrays are fabricated by photoetching and tested using a high-speed sand erosion rig. Under the same impact conditions, the erosion rates of the micro/nanostructured titanium surfaces were similar to those of smooth titanium alloy, implying that the hydrophobic surface fabricated on the bulk material had erosion-resistant capabilities. The material loss mechanisms of the micro/nanostructures under different impact angles were compared, providing useful information for the future optimization of micro/nanostructures with the goal of improved erosion resistance.

Analysis In Vivo of Bone Modulation in Hydrophilic and Hydrophobic Titanium Implant Surfaces.

To evaluate whether a hydrophilic surface treatment compared with a hydrophobic implant surface can enhance osseointegration by analysis of calcium deposition, bone-to-implant contact (BIC), bone volume (BV), and upregulation of genes involved in bone formation. Sixty implants (n = 60) with a hydrophobic (SAE) or hydrophilic (SAE-HD) surface treatment were placed bilaterally in each femur of 3-month-old male mice (n = 30). Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were utilized for quantifying the presence of calcium on the implant surface 7 days after implant placement. The specimens were analyzed after 14 and 21 days for BIC and BV by Nano CT scanning followed by histologic evaluation. Additionally, 1, 3, and 7 days postsurgery, femurs were harvested, implants were explanted, and gene expression (Sp7, Bsp, Sost, IL-1α, and IL-10) by quantitative real-time polymerase chain reaction was studied. Moreover, implants were characterized for surface roughness area. Data were statistically analyzed with two-way analysis of variance (ANOVA) followed by the Tukey test (P < .05). The amount of calcium on the surface was higher for SAE-HD after 7 days. Nano CT revealed significantly more BV in the SAE-HD than the SAE surface. The histologic assessment showed increased BIC in SAE-HD in comparison to SAE. SAEHD showed significantly increased levels of genes involved in bone formation. Both surfaces were able to modulate bone responses toward osteoblast differentiation. SAE-HD presented a better response compared with SAE.

Effectivity of homecare and professional biofilm removal procedures on initial supragingival biofilm on laser-microtextured implant surfaces in an ex vivo model

BackgroundThe aim of the current study was the evaluation of initial biofilm adhesion and development on laser-microtextured implant collar surfaces and the examination of effectivity of different biofilm management methods.MethodsInitial biofilm formation was investigated on hydrophobic machined and laser-microtextured (Laser-Lok) titanium surfaces and hydrophobic machined and laser-microtextured (Laser-Lok) titanium aluminium vanadium surfaces and compared to hydrophobic smooth pickled titanium surfaces, hydrophilic smooth and acid etched titanium surfaces, hydrophobic sandblasted large grid and acid etched titanium surfaces (titanium Promote) via erythrosine staining and subsequent histomorphometrical analysis and scanning electron microscopic investigations. After decontamination procedures, performed via tooth brushing and glycine powder blasting, clean implant surface was detected via histomorphometrical analysis.ResultsAfter 24 h mean initial plaque area was detected in the following descending order: smooth pickled titanium > titanium Promote > hydrophilic smooth and acid etched titanium > Laser-Lok titanium > Laser-Lok titanium aluminium vanadium. The same order was determined after 48 h of biofilm formation. After glycine powder blasting all samples depicted almost 100% clean implant surface. After tooth brushing, Laser-Lok titanium (67.19%) and Laser-Lok titanium aluminium vanadium (69.80%) showed significantly more clean implant surface than the other structured surfaces, hydrophilic smooth and acid etched titanium (50.34%) and titanium Promote (33.89%). Smooth pickled titanium showed almost complete clean implant surface (98.84%) after tooth brushing.ConclusionsBoth Laser-Lok surfaces showed less initial biofilm formation after 24 and 48 h than the other implant surfaces. In combination with the significant higher clean implant surfaces after domestic decontamination procedure via tooth brushing, both Laser-Lok surfaces could be a candidate for modified implant and abutment designs, especially in transmucosal areas.

Coating of a Sand-Blasted and Acid-Etched Implant Surface with a pH-Buffering Agent after Vacuum-UV Photofunctionalization

Ultraviolet (UV) photofunctionalization can reset the biological aging of titanium after the preparation and storage of dental implants by transforming hydrophobic titanium surfaces into superhydrophilic surfaces. Blood clot formation around the implant can initialize and promote the healing process at the bone–implant interface. The aim of this study is to evaluate and compare the capabilities of surface wettability and blood clotting of implants with a conventional sand-blasted and acid-etched surface (SA), a sand-blasted and acid-etched surface with vacuum-UV treatment (SA + VUV), and a sand-blasted and acid-etched surface coated with a pH-buffering agent after vacuum-UV treatment (SA + VUV + BS). Static and dynamic tests for surface wettability and blood clotting were performed in vitro for SA + VUV and SA + VUV + BS (n = 5), while hemostasis resulting from blood clotting was evaluated in vivo for SA, SA +VUV, and SA + VUV + BS (n = 4). A Kruskal–Wallis test showed statistically significant differences (p &lt; 0.05) in all tests, with the exception of in vitro test of static blood clotting. VUV treatment is therefore effective at making an SA surface superhydrophilic as an alternative to routine UV-C radiation. The addition of a pH-buffering agent to SA + VUV also improved surface wettability and blood clotting, which are crucial for successful osseointegration.

Investigating the Response of Human Neutrophils to Hydrophilic and Hydrophobic Micro-Rough Titanium Surfaces.

Various treatments have been used to change both the topography and chemistry of titanium surfaces, aiming to enhance tissue response and reduce healing times of endosseous implants. Most studies to date focused on bone healing around dental implants occurring later during the healing cascade. However, the impact of the initial inflammatory response in the surgical wound site on the success and healing time of dental implants is crucial for implant integration and success, yet it is still poorly understood. The purpose of this study was to investigate the effect of titanium surface hydrophilicity on the response of human neutrophils by monitoring oxygen radical production, which was measured as chemiluminescence activity. Materials and Methods: Neutrophils were isolated from human donors’ blood buffy coats using the double sucrose gradient method. Neutrophils were exposed to both hydrophilic and hydrophobic titanium surfaces with identical topographies in the presence and absence of human serum. This resulted in six experimental groups including two different implant surfaces, with and without exposure to human serum, and two control groups including an active control with cells alone and a passive control with no cells. Two samples from each group were fixed and analyzed by SEM. Comparisons between surface treatments for differences in chemiluminescence values were performed using analysis of variance ANOVA. Results and Conclusion: In the absence of exposure to serum, there was no significant difference noted between the reaction of neutrophils to hydrophilic and hydrophobic surfaces. However, there was a significant reduction in the mean and active chemiluminescence activity of neutrophils to serum-coated hydrophilic titanium surfaces than to serum-coated hydrophobic titanium surfaces. This suggests that surface hydrophilicity promotes enhanced adsorption of serum proteins, which leads to decreased provocation of initial immune cells and reduction of local oxygen radical production during wound healing. This can help explain the faster osseointegration demonstrated by hydrophilic titanium implants.

Femtosecond laser manipulating underoil surface wettability for water removal from oil

The oil containing a small amount of water droplets have induced serious operation malfunctions for precision industrial equipment and even brought fatal disasters, which have aroused widespread concern. However, developing an effective strategy for removal of water from oil is still an enormous challenge. Here, we present a rapid and facile method for fabricating underoil superhydrophilic surface by one-step femtosecond laser direct writing technology. Interestingly, two extreme underoil wettability statuses can be achieved through tuning the scanning velocity (V). Concretely, the pristine underoil hydrophobic titanium sheet will become underoil superhydrophilicity when V is 0.1 m/s, while it will exhibit underoil superhydrophobicity when V increases to 3 m/s. Moreover, the underoil superhydrophilic surface shows excellent water absorption, which could realize the purification of oil contains water droplets regardless of the oil types, and the corresponding mechanism is propounded. We believe that femtosecond laser micromachining has tremendous superiority in solving the problem of oil containing water droplets.

A Facile Approach of Thin Film Coating Consisted of Hydrophobic Titanium Dioxide over Polypropylene Membrane for Membrane Distillation

In this work, the hydrophobic modification of TiO2 nanoparticles (HTiO2) was carried out by reacting with dodecylphosphonic acid (DDPA) and hexylamine solution. A facile approach of the self-assembly technique was used for the coating of hydrophobic HTiO2 layer over the microporous polypropylene (PP) membrane. The self-assembled layer was formed between the interface of trimesoyl chloride (TMC) (in hexane) and trimethylamine (in water) solutions. The high porosity for the coated membranes ascribed to the selfassembled trimesic acid (TMA) layer and its potential to generate open and loosely packed, two-dimensional hydrogen-bond networks on the membrane surface. The dispersion of HTiO2 was accomplished in the TMC in hexane leading hydrophobic and porous surfaces than the neat PP membrane. The initial average pore size of the PP membrane was reduced from 0.4 μm to 0.2 μm with a coating of 2.0 wt% of HTiO2. The new membranes showed high reliability, high rejection, and water flux during the real seawater desalination tested in direct contact membrane distillation (DCMD) configuration. The maximum transmembrane permeate flux of 45.4 kg/m2h with >98% salt rejection was obtained for the coating layer with 2.0 wt% HTiO2 at 80oC demonstrating the future potential application towards seawater desalination.

A simple, rapid and single step method for fabricating superhydrophobic titanium surfaces with improved water bouncing and self cleaning properties

We report a simple, rapid, inexpensive and eco-friendly method for fabricating super hydrophobic (SHP) titanium surface using ethanolic solution of myristic acid and HCl through simultaneous anodization and adsorption. The coating performance is optimized by varying the anodization potential, acidic concentration and anodization duration. The prepared superhydrophobic surfaces are characterized using water contact angle (WCA), Fourier transform infrared (FTIR) spectroscopy, Laser Raman Spectroscopy (LRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX). At an optimal anodization potential, the coated surface is found to be densely populated with hierarchical micro-nanoclusters of titanium dioxide adsorbed with myristic acid, exhibiting a maximum WCA of 176.3°±1° with a sliding angle of 1°. SHP surface showed surface features with layered ridges decorated with submicron sized aggregates. The liquid-air area fraction on the prepared SHP surface is ~0.97, with an asperity slope ψ > 71°. SHP surface exposed to microbial cultures for 48 h showed 50% reduction in bacterial adhesion. Bouncing dirt removal and bouncing of drops suggest better cleaning efficacy and excellent water repellency of the SHP surface. The fast fabrication, excellent anti biofouling, chemical and mechanical stability of the SHP coating offer interesting applications, and also opens up new ways for creating stable superhydrophobic titanium surfaces with excellent self cleaning characteristics.

Experimental Investigation of Condensation and Freezing Phenomenon on Hydrophilic and Hydrophobic Titanium Nanopillared Glass Surfaces

Atmospheric condensation is very important for multiple practical applications such as heat transfer, thermal management, aerospace, and condensate harvesting. Water droplets heterogeneously nucleate on the surfaces when the temperature is below the dew point temperature. The nucleation energy barrier for a condensed droplet varies significantly with the humidity content in the operating environment. The freezing of this condensate is also dependent on the operating conditions and surface properties. This article presents an experimental study of condensation and freezing from humid air with the objective of understanding how the surface morphology and chemistry determines the droplet shape and wetting state. Hexagonal close-packed arrays of titanium (Ti) pillars are patterned using microsphere photolithography (MPL). The Ti nanostructured surface was tested with and without a Teflon© coating to reveal the condensate harvesting, passive freezing, and dropwise condensation applications, respectively. Condensation and freezing tests were conducted in the presence of non-condensable gases (air) with different relative humidity (RH) levels to control the nucleation site density. The experiments showed that droplet growth occurs in the following stages: initial nucleation, direct growth, and coalescence events. By pinning droplets, coalescence is suppressed for the Ti nanopillared surface altering the size distribution of droplets and significantly accelerating the freezing process.

A hydrophobic titanium doped zirconium-based metal organic framework for photocatalytic hydrogen peroxide production in a two-phase system

A hydrophobic Ti doped Zr-based MOF was synthesized and used for photocatalytic H2O2 production in a two-phase system (water/benzyl alcohol).

Mechanism investigation on the enhanced photocatalytic oxidation of nonylphenol on hydrophobic TiO2 nanotubes

Enhanced and selective photocatalytic oxidation of nonylphenol (NP), a typical hydrophobic endocrine disrupting chemicals (EDCs), was realized on hydrophobic titanium dioxide nanotubes (H-TiO2NTs), which was fabricated by an electrochemical anodization method, followed by grafting of perfluorooctyl groups. The water contact angle of catalyst surface changed from 21.1° to 128.4° after hydrophobic modification. H-TiO2NTs showed excellent photocatalytic oxidation performance for NP, that it was completely converted in 40 min under irradiation, which was improved for about 17% compared with the hydrophilic TiO2NTs. The enhanced photocatalytic performance of H-TiO2NTs was attributed to the stronger adsorption ability toward NP identified by ATR-FTIR, with an initial adsorption rate of 4 times as higher as that of bare TiO2NTs. Meanwhile, the hydrophobic surface of H-TiO2NTs was beneficial for generation of more hydroxyl radicals. The apparent rate constant of hydroxyl radicals’ generation on H-TiO2NTs, which was the main oxidizing species, could reach 1.83 times that of the hydrophilic TiO2NTs. Both the two factors contributed to the successful competition of NP against the coexistent hydrophilic contaminates in the adsorption and oxidation on the catalyst surface, leading to the selective removal of NP in mixed systems finally.

PR591: Pro‐osteogenic properties of hydrophilic and hydrophobic titanium surfaces. Crosstalk between signalling pathways in in vivo models

PR591: Pro‐osteogenic properties of hydrophilic and hydrophobic titanium surfaces. Crosstalk between signalling pathways in in vivo models

Pro-osteogenic properties of hydrophilic and hydrophobic titanium surfaces: Crosstalk between signalling pathways in in vivo models.

It is now generally accepted that the response to a particular signal, such as the surgical trauma following implant placement, is not the result of a single linear signalling pathway, but rather reflects pathway integration, which can occur at multiple levels. Although it is well documented that both SLA and SLActive surfaces are able to promote bone formation and osseointegration, it is still unclear which are the key signalling pathways involved and how surface hydrophilicity/hydrophobicity might affect pathway integration. To combine gene and protein data from in vivo studies applying titanium hydrophobic (Sandblasting, Large-grit, Acid-etching, SLA) and hydrophilic (SLActive) surfaces to understand the molecular mechanisms responsible for the pro-osteogenic properties of these surfaces. The Kyoto Encyclopedia of Genes and Genomes (KEGG® ) pathway database and the Ingenuity® Pathway Analysis (IPA® ) software were applied to the genomic and proteomic data of previous in vivo studies applying SLA and SLActive surfaces, with the specific aim to focus on bone formation-related signalling pathways. While gene data were derived from a human study on osseointegration, protein data originated from a preclinical study in rabbits. Data were available for the 4, 7 and 14days of healing periods. Both genomic and proteomic data showed that the osteogenesis process takes place mainly at 7 and 14days of healing on both SLA and SLActive surfaces. Surface hydrophilicity enhances bone formation at multiple levels, by directly promoting an earlier expression of pathways involved in cell proliferation and osteoblast precursor differentiation (eg, mitogen-activated protein kinase, phosphoinositide-3 kinase-AKT, Wnt, Notch, transforming growth factor-β), but also by positively regulating angiogenesis, bone mineralization and bone remodelling. This study combined, for the first time, different 'omics' outputs to get new insights on the molecular mechanisms behind the influence of surface hydrophilicity on osseointegration/bone formation. Specific signalling pathways, such as Wnt, vascular endothelial growth factor and mitogen-activated protein kinase, were identified as differentially modulated by titanium surface hydrophilicity both at a genomic and proteomic level. These findings may be used in the future to monitor/predict the bone formation/osseointegration process, or as a screening tool towards the manufacture of new pro-osteogenic implant surfaces. In order to take into account the full complexity and interplay of cell signalling during bone formation, powerful bioinformatics tools integrating different 'omics' data and predicting signalling pathways trends should be applied by future studies.

Methacrylate-Stitched β-Cyclodextrin Embedded with Nanogold/Nanotitania: A Skin Adhesive Device for Enhanced Transdermal Drug Delivery.

Transdermal (TD) drug delivery is a more attractive technique for drug delivery compared to oral and intravenous injection. However, the permeation of drug molecules across the skin is difficult due to the presence of highly ordered lipid barrier. This study details the development of a novel TD system, which has the potential to simultaneously enhance the skin permeability and adhesion behavior. Ibuprofen (IP) was selected as model drug. The ability of gold nanoparticle (AuNP) and hydrophobic titanium nanotube (TNT) to enhance the skin permeability was explored. Additionally, β-cyclodextrin (βCD), which can exceptionally encapsulate poorly water-soluble drugs, is grafted with methacrylates to improve the skin adhesion property. Finally, Au-TNT nanocomposite was deposited onto methacrylate-grafted βCD matrix. The developed material was characterized through NMR spectroscopy, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The characteristics of the film, including water vapor permeability (WVP), thermomechanical properties, etc., were examined in terms of Au-TNT content. The TD delivery of IP with different concentrations of Au-TNT was evaluated via an in vitro skin permeation study through rat skin. It is revealed that the prepared TD film exhibited an improved drug-delivery performance due to the synergistic action of AuNP and hydrophobic TNT. The cumulative percent of IP delivered across the skin is extremely depending on nanofiller content, lipophilicity, and thickness of the membrane, and the device incorporated with 4.0% Au-TNT displayed the best performance. In addition, a study on storage stability was performed by storing the films for 2 months at different temperatures. The study revealed that the device possessed excellent storage stability when stored at low temperature. The developed film offers excellent WVP, drug encapsulation efficiency, thermomechanical properties, and skin adhesion behavior. Moreover, the device was cosmetically attractive, noncytotoxic, and resistant to microbial growth and hence extremely reliable for skin application. The developed skin permeation strategy may open new avenues in TD drug delivery.

Using sewage sludge pyrolytic gas to modify titanium alloy to obtain high-performance anodes in bio-electrochemical systems

Titanium is under consideration as a potential stable bio-anode because of its high conductivity, suitable mechanical properties, and electrochemical inertness in the operating potential window of bio-electrochemical systems; however, its application is limited by its poor electron-transfer capacity with electroactive bacteria and weak ability to form biofilms on its hydrophobic surface. This study reports an effective and low-cost way to convert a hydrophobic titanium alloy surface into a hydrophilic surface that can be used as a bio-electrode with higher electron-transfer rates. Pyrolytic gas of sewage sludge is used to modify the titanium alloy. The current generation, anodic biofilm formation surface, and hydrophobicity are systematically investigated by comparing bare electrodes with three modified electrodes. Maximum current density (15.80 A/m2), achieved using a modified electrode, is 316-fold higher than that of the bare titanium alloy electrode (0.05 A/m2) and that achieved by titanium alloy electrodes modified by other methods (12.70 A/m2). The pyrolytic gas-modified titanium alloy electrode can be used as a high-performance and scalable bio-anode for bio-electrochemical systems because of its high electron-transfer rates, hydrophilic nature, and ability to achieve high current density.

Fabrication of hydrophobic coating on filter paper from self-emulsifying carnauba wax-alcohol emulsions with nano-TiO2 particles for water/diesel separation

Carnauba wax is a natural material with high hydrophobicity. In this study, molten carnauba wax was stably self-emulsified in ethanol without using additional emulsifiers. Hydrophobic titanium dioxide (TiO2) nanoparticles were dispersed into carnauba wax-ethanol emulsion to form a composite coating on filter paper. The results showed that immersion in the composite coating that contained wax and hydrophobic TiO2 conveyed to filter paper good hydrophobicity (water contact angle over 140°) and stability against acid or alkali solution. The scanning electron microscopy (SEM) images indicated the presence of micro bead/flake structures on the surface of filter paper. These obtained filter papers could effectively expel water from a water/diesel mixture. The water content in the water/diesel mixture decreased from 10% to 0.01% through the separation from the filter paper.

Composite anion exchange membranes with functionalized hydrophilic or hydrophobic titanium dioxide

Composite anion exchange membranes based on polysulfone with grafted 1,4-diazabicyclo[2.2.2]octane (DABCO) and surface functionalized TiO2 nanoparticles were prepared and characterized. Tri(hydroxymethyl)propane (TMP) was used for hydrophilic and polymethyl-hydrosiloxane (PMHS) for hydrophobic surface functionalization. Thermal analysis (TGA and DSC) showed water loss, the loss of quaternary ammonium groups around 300 °C and the backbone decomposition above 400 °C starting from the quaternary carbon. The decompositions were confirmed by temperature-dependent FTIR spectroscopy. The thermomechanical study (DMA) showed a secondary relaxation, probably due to DABCO side groups motions, around 130 °C followed by the glass transition around 250 °C and by a partial crystallization of the polymer, which is also observed by DSC. The increase of storage modulus observed for the composites is consistent with their reduced hydration, which is confirmed by water uptake measurements. Atomic Force Microscopy observations show a more homogeneous dispersion of hydrophobic TiO2 nanoparticles, which are also well embedded in the polymer, whereas agglomeration is evident for hydrophilic surface treatment. The contact angle with water decreases strongly in composites with TMP-TiO2. The ionic conductivity is higher for PMHS-TiO2, probably related to the more homogeneous filler distribution with lower agglomeration.