Liquid Phase Deposition Research Articles

Titanium Dioxide Covalently Immobilized Citric Acid (TiO2‐CA) Nanohybrid Coating of Neurovascular Flow Diverter to Improve Antithrombogenic and Pro‐Endothelialization Properties

AbstractBraided neurovascular flow diverters (FDs) have revolutionized the treatment of aneurysms. However, dual antiplatelet therapy is mandatory for patients with FDs, which increases the risk of adverse side effects like bleeding complications. Surface modification would be of critical relevance to improve the biocompatibility and therefore clinical performance of FDs. Herein, a titanium dioxide (TiO2) covalently immobilized citric acid (CA) nanohybrid coating is fabricated on nitinol (NiTi) braided FDs by liquid phase deposition and dip‐coating, to inhibit thrombosis and promote re‐endothelialization. The CA molecules are covalently bound onto the pre‐deposited TiO2 nanoparticulate coating. The coating has a unique homogenously nanostructured morphology as well as super‐hydrophilicity. Both in vitro and in vivo results verify that the coated samples inhibit platelets and fibrinogen adhesion, delay coagulation time, and concomitantly promote re‐endothelialization. Such appealing properties are ascribed to the nature of CA and TiO2 per se as well as the nanostructured morphology. The present strategy may not only provide a new avenue to surface‐modify braided neurovascular FDs but also shed light on advanced nanohybrid materials for biomedical applications among others.

In situ construction of Co@nitrogen-doped carbon/Ni nanocomposite for broadband electromagnetic wave absorption

The tunable multicomponent synergistic loss mechanism and multiple heterogeneous interfaces of magnetic carbon-based composites have emerged as the efficient electromagnetic wave absorbing (EMWA) materials. Herein, the Ni(OH)2/ZIF-67 precursors were synthesized via the hydrothermal and liquid-phase deposition methods, and then carbonized at different temperature under N2 atmosphere to obtain Co@nitrogen-doped carbon/Ni (Co@NC/Ni) nanocomposites. The metallic components with good dispersion property provided magnetic loss and improved impedance matching. Meanwhile, they also acted as catalysts to induce the formation of graphitized carbon, enhancing the conductive loss. Furthermore, more heterogeneous interfaces and defects were generated inside the sample, which promotes dielectric loss. Therefore, the Co@NC/Ni nanocomposite (carbonized at 600 °C) exhibited excellent EMWA performance with a minimum reflection loss (RL) of −47.10 dB, and the effective absorption bandwidth (RL ≤ −10 dB) can reach 6.84 GHz at 2.5 mm with a filling ratio of 30%. This work provides a heterogeneous interface construction strategy for the future application of high-performance magnetic carbon based EMWA materials.

Synthesis and Electrochemical Performance of V6O13 Nanosheets Film Cathodes for LIBs

V6O13 thin films were deposited on indium-doped tin oxide (ITO) conductive glass by a concise low-temperature liquid-phase deposition method and through heat treatment. The obtained films were directly used as electrodes without adding any other media. The results indicate that the film annealed at 400 °C exhibited an excellent cycling performance, which remained at 82.7% of capacity after 100 cycles. The film annealed at 400 °C with diffusion coefficients of 6.08 × 10-12 cm2·s-1 (Li+ insertion) and 5.46 × 10-12 cm2·s-1 (Li+ extraction) in the V6O13 film electrode. The high diffusion coefficients could be ascribed to the porous morphology composed of ultrathin nanosheets. Moreover, the film endured phase transitions during electrochemical cycling, the V6O13 partially transformed to Li0.6V1.67O3.67, Li3VO4, and VO2 with the insertion of Li+ into the lattice, and Li0.6V1.67O3.67, Li3VO4, and VO2 partially reversibly transformed backwards to V6O13 with the extraction of Li+ from the lattice. The phase transition can be attributed to the unique structure and morphology with enough active sites and ions diffusion channels during cycles. Such findings reveal a bright idea to prepare high-performance cathode materials for LIBs.

Terahertz Enhanced Sensing of Uric Acid Based on Metallic Slot Array Metamaterial.

An enzyme-free terahertz uric acid sensor based on a metallic slot array metamaterial was proposed and realized both theoretically and experimentally. The sensing model was verified in simulation and femtosecond laser processing technology was employed to ablate slots in the copper plate to fabricate metamaterials. Analytes were tested with liquid phase deposition on the metamaterial by a terahertz frequency domain spectroscopy system. Gradient concentrations of uric acid, ascorbic acid, and a mixture of them were measured separately with a good linear response. A significant decrease in sensitivity was observed in the ascorbic acid assay compared with the uric acid assay. The test results of the mixture also proved that our device is resistant to ascorbic acid. It is a simple and effective method for monitoring uric acid concentrations and the strategy of eliminating interference while modulating the resonance peak location mentioned here can be rationally projected for the development of other sensors.

Silicone Nanofilament Coatings as Flexible Catalyst Supports for a Knoevenagel Condensation Reaction in Batch and Flow Systems.

In this work, silicone nanofilament (SNF) coatings were prepared via a droplet-assisted growth and shaping (DAGS) approach, where the preparation of the coatings is allowed under ambient conditions. The application of SNF coatings as catalyst supports for amino moieties from (3-aminopropyl)triethoxysilane (APTES) was investigated. With the optimized coating conditions identified, the Brunauer-Emmett-Teller surface areas of a bare glass filter substrate and bare glass beads after the coating have increased by 5-fold and 16-fold, respectively. The SNF-coated filters were readily functionalized with amino groups via a liquid-phase deposition process, and their catalytic activities for a Knoevenagel reaction were evaluated using a batch reactor and a packed bed reactor. In both reactors, the as-prepared filters demonstrated superior catalytic performance over the functionalized filters without SNF coatings. Notably, the unique flexibility of the SNF coatings allowed the facile preparation of a packed bed reactor and a scalable catalytic system. It is expected that the packed bed system established in this study will support the development and the use of various SNF-supported organocatalysts and catalytic materials.

Assessing advanced methods in XPS and HAXPES for determining the thicknesses of high-k oxide materials: From ultra-thin layers to deeply buried interfaces

We assess advanced XPS-based methods in determining depth distribution in alumina and hafnia ALD samples of increasing thicknesses and buried layer depths. First, dose quantification of Al in ultrathin alumina is achieved through non-destructive wavelength dispersive X-ray fluorescence (WDXRF), which is confirmed by comparison to destructive liquid-phase deposition inductively coupled plasma mass spectrometry (LPD-ICPMS) (uncertainty 10 %). Second, we compare WDXRF to parallel ARXPS (pARXPS) in precise dose and thickness quantification in ultrathin alumina, and present the ability of pARXPS to accurately track linear growth during the deposition. Thickness determination of an intermediate ALD stack of silicon dioxide, hafnia, and alumina layers of 1–2 nm by pARXPS is evaluated against quantitative, reference-free grazing incidence X-ray fluorescence (GIXRF) (uncertainty 8–9 %). An alternative technique employing inelastic background analysis (IBA) is introduced as a fast and accurate method and subsequently compared with pARXPS and GIXRF thickness determinations. Finally, in thicker multilayer systems, hard X-ray photoelectron spectroscopy (HAXPES) combined with IBA is proposed for an in-depth analysis for thicknesses up to 28 nm, with generated interface locations and layer thicknesses well-aligned to nominal values. This study is a novel application of lab-based Cr-Kα HAXPES spectra for inelastic background analysis in thick metal-oxide multilayer materials.

The Combined Action of Organic Inhibitors on Copper and Aluminium Metals and Aluminium Alloy Containing Copper

The approach used in the present work involves investigating the corrosion protection properties of mixed inhibitors for copper and aluminium substrates in chloride-containing solutions, which serve as a benchmark for studies of the alloy AA2024, with Cu and Al being the main culprits for localized corrosion. A synergistic mixture of inhibitors could find potential applications in novel blending combinations, such as in cooling water as an inhibitor in closed systems or incorporated in various protective coatings as additives, nano-containers, etc. If possible, the protective inhibitor film should show irreversibility of inhibition which can be defined as the ability to, once formed, retains its protective properties when the concentration of the corrosion inhibitor decreases. This irreversibility of the protective properties is essential for long-term protection.Inhibitory action of organic molecules, 2-mercaptobenzimidazole (MBI) and octylphosphonic acid (OPA) and their binary combinations on aluminium, copper and aluminium alloy 2024-T3 was investigated in chloride environments by conventional electrochemical methods and surface-analytical techniques [1,2]. In addition, the influence of pre-treatment of the metal surface and the choice of solvent for liquid-phase deposition on adsorption of MBI and OPA was studied on individual metals, Al and Cu [3]. Although OPA is not an inhibitor for Cu, it can synergistically boost corrosion inhibition of copper when added to MBI. In contrast, a synergistic effect between MBI and OPA as corrosion inhibitors was not observed for AA2024-T3. The mechanism was proposed where the thickness and structure of the surface layer are dependent on the pH. For the sample exposed to MBI at pH 5.5, where the Cu2O is stable, a thin Cu(I)MBI film is formed.In contrast, when exposed to the mixture of MBI and OPA at a pH of 4, the amount of produced Cu+ ions is boosted, and a much thicker Cu(I)MBI film forms by dissolution-precipitation mechanism. This layer exhibits high inhibitory effectiveness on copper substrate. At even lower pH, the thick compact Cu(I)MBI film does not form due to intensive dissolution of the Cu2O underlayer, resulting in a voluminous product. The postulated mechanism is confirmed by electrochemical data and composition of the layer by X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectroscopy and focused-ion beam scanning electron microscopy with chemical analysis.Immersion of AA2024 in an OPA-containing solution caused significant localized corrosion, while no local electrochemical activity on AA2024 was detected in an MBI-containing solution, indicating that the MBI inhibitor was very effective against pitting corrosion. Figure shows FIB/SEM (cross-section) analysis of local corrosion induced by Al2CuMg phase after 24 h immersion of AA2024 in 3 wt.% NaCl containing 1 mM MBI. The chemical analysis employed at the cross-section (yellow rectangles) of the Al2CuMg revealed that the MBI layer reduces the dissolution rate of dealloying of this phase and the rate of oxygen reduction on the copper remnant sites.This study shows that the behaviour of each combination of inhibitor and metal substrate is unique and cannot be translated to the more complex system such as alloy. Therefore, a profound understanding of the inhibition mechanism of individual metals is a prerequisite for further investigation of the corrosion inhibition of aluminium alloys. Acknowledgements: The financial support of the project by the Slovenian Research Agency is acknowledged (grants No. P1-0134, P2-0393 and BI-US/22-24-140) is acknowledged. Barbara Kapun, BSc, is acknowledged for FIB-SEM-EDS analysis.

One-Stage Femtosecond Laser-Assisted Deposition of Gold Micropatterns on Dielectric Substrate.

In this study, a simple one-stage laser-assisted metallization technique based on laser-induced backside wet etching and laser-induced chemical liquid-phase deposition is proposed. It allows for the fabrication of gold micropatterns inside the laser-written trace on a glass substrate. The reduction and deposition of gold inside and outside the laser-ablated channel were confirmed. The presence of Au nanoparticles on the surface of the laser-written micropattern is revealed by atomic force microscopy. The specific resistivity of the gold trace formed by ultrafast light-assisted metal micropatterning on a dielectric glass substrate is estimated as 0.04 ± 0.02 mΩ·cm. The obtained results empower the method of the selective laser-assisted deposition of metals on dielectrics and are of interest for the development of microelectronic components and catalysts, heaters, and sensors for lab-on-a-chip devices.

Fabrication of flower-like Ag/lignin composites and application in antibacterial fabrics

The bacterial infection and its transmission pose a great threat to life and health, which leads to the urgent development of efficient and broad-spectrum antibacterial agents. Herein, Ag/lignin layered nanoflower (Ag/EHL-CM-0.05) was synthesized by using biomass lignin as reducing and capping agents and silver nitrate as precursor. The study showed that the size distribution of Ag NPs was uniform distribution and about 20–40 nm. The crystal surface of Ag NPs was Ag (111) surface. The minimum inhibitory concentration of Ag/EHL-CM-0.05 against E. coli and S. aureus was all 7.8 μg/mL, which was the lowest of other Ag/lignin antibacterial materials and reached a level nearly as polycationic antibacterial agents. The antibacterial mechanism suggested that Ag/EHL-CM-0.05 could release OH and Ag+, which could cause bacterial death. Finally, Ag/EHL-CM-0.05 was sprayed onto the viscose fabrics by liquid-phase spray deposition method. It was found that the inhibition zone diameter of modified viscose fabrics against E. coli and S. aureus only dropped about 0.16 cm on average after friction treatment and 0.32 cm on average after washing treatment. This work provides a new idea for the design and synthesize of efficient, broad-spectrum, and bio-compatible antibacterial agents, which has important social, economic, and environmental significance.

Intelligent Coatings with Controlled Wettability for Oil-Water Separation.

Intelligent surfaces with controlled wettability have caught much attention in industrial oily wastewater treatment. In this study, a hygro-responsive superhydrophilic/underwater superoleophobic coating was fabricated by the liquid-phase deposition of SiO2 grafted with perfluorooctanoic acid. The wettability of the surface could realize the transformation from superhydrophilicity/underwater superoleophobicity (SHI/USOB) to superhydrophobicity/superoleophilicity (SHB/SOI), both of which exhibited excellent separation performance towards different types of oil–water mixtures with the separation efficiency higher than 99%. Furthermore, the long-chain perfluoroakyl substances on the surface could be decomposed by mixing SiO2 with TiO2 nanoparticles under UV irradiation, which could reduce the pollution to human beings and environment. It is anticipated that the prepared coating with controlled wettability could provide a feasible solution for oil–water separation.

Synthesis of Ti6Al4V/SrFHA Composites by Microwave-Assisted Liquid Phase Deposition and Calcination.

The feasibility of synthesis of Ti6Al4V/SrFHA (Ca9.37Sr0.63(PO4)6F2) composites via coating strontium and fluorine co-doped HA to Ti6Al4V substrate by microwave-assisted liquid phase deposition and calcination was evaluated, with a focus on the effect of the deposition temperature from 30 °C to 70 °C. The outcomes demonstrate that strontium and fluorine can be successfully doped into HA to form a SrFHA coating with modified micromorphology which is deposited on the alloy. When the deposition temperature was 50 °C, the coating with the largest uniform continuous SrFHA coverage was obtained. After calcination, the adhesion strength and Vickers microhardness of the Ti6Al4V/SrFHA composite increased from 0.68 MPa and 323 HV to 2.41 MPa and 329 HV, respectively, with a decrease in the water contact angle from 10.88° to 7.24°, exhibiting enhancement of both mechanical properties and wettability. Moreover, the composite obtained at the deposition temperature of 50 °C exhibited good bioactivity based on the simulate body fluid (SBF) test. On account of the above features primarily as a result of the combined effect of the co-doping of strontium and fluorine, high crystallinity of SrFHA, large surface roughness, and formation of the titanium oxide transition layer, the Ti6Al4V/SrFHA composite shows great potential in dental implantology.

Corrosion inhibition of copper and aluminium by 2-mercaptobenzimidazole and octylphosphonic acid—Surface pre-treatment and method of film preparation

The optimal surface pre-treatment conditions for improved adsorption of 2-mercaptobenzimidazole (MBI) and octylphosphonic acid (OPA) on copper and aluminium substrates are presented. For this purpose, mechanical and chemical pre-treatments were employed, which included grinding/polishing and etching/desmutting, respectively. In addition, organic films for both pre-treated samples were prepared by liquid-phase deposition from ethanol or an aqueous solution containing MBI and OPA inhibitors. The mechanism of formation and degradation of the films on Cu and Al samples in 3 wt.% NaCl were investigated by electrochemical methods, whereas morphology and bonding of inhibitors were studied by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. It was shown that the surface pre-treatment did not significantly influence the chemistries of Cu and Al. However, the method of film formation, including the use of two different solvents, was crucial. The inhibitor films on Cu and Al were not formed in an ethanol solution but only deposited from aqueous solutions. A significant reduction in corrosion current density revealed that MBI is an effective inhibitor for Cu, while this characteristic is absent for Al. On the other hand, OPA behaves the other way around.

Novel synthesis of SiC coating by liquid phase deposition

ABSTRACT In this study, SiC coating was prepared on carbon fibres from solution at ambient temperatures for the first time. The thickness of the coating was ∼85 nm. Analysis of the coatings revealed the presence of only SiC in the coating. The initial oxidation temperature of the SiC-coated carbon fibres increased by ∼50°C and the complete oxidation temperature was increased by ∼167°C, indicating excellent oxidation resistance owing to the presence of the SiC coating. We believe that the excellent properties and easy preparation process of SiC coating reported in this paper would provide us with a new way to produce SiC coating on carbon substrates.

Aqueous solution reaction during liquid-phase deposition and its application in electrochemical materials

Aqueous solution reaction during liquid-phase deposition and its application in electrochemical materials

Designing Highly Efficient Cu2O-CuO Heterojunction CO Oxidation Catalysts: The Roles of the Support Type and Cu2O-CuO Interface Effect.

In this work, a series of Cu2O/S (S = α-MnO2, CeO2, ZSM-5, and Fe2O3) supported catalysts with a Cu2O loading amount of 15% were prepared by the facile liquid-phase reduction deposition–precipitation strategy and investigated as CO oxidation catalysts. It was found that the Cu2O/α-MnO2 catalyst exhibits the best catalytic activity for CO oxidation. Additionally, a series of Cu2O-CuO/α-MnO2 heterojunctions with varied proportion of Cu+/Cu2+ were synthesized by further calcining the pristine Cu2O/α-MnO2 catalyst. The ratio of the Cu+/Cu2+ could be facilely regulated by controlling the calcination temperature. It is worth noting that the Cu2O-CuO/α-MnO2-260 catalyst displays the best catalytic performance. Moreover, the kinetic studies manifest that the apparent activation energy could be greatly reduced owing to the excellent redox property and the Cu2O-CuO interface effect. Therefore, the Cu2O-CuO heterojunction catalysts supported on α-MnO2 nanotubes are believed to be the potential catalyst candidates for CO oxidation with advanced performance.

Deposit Formation in a Coal-Fired Rotary Kiln for Fluxed Iron Ore Pellet Production: Effect of MgO Content

During the roasting process of fluxed pellets in a coal-fired rotary kiln, the incomplete combustion of pulverized coal injection accelerates deposit formation, which further limits the production efficiency of fluxed pellets. In order to eliminate the above problem, this study investigated the influence of MgO on deposit formation mechanism. The thermodynamic analysis revealed that MgO could increase the melting temperature of silicates in fluxed pellets with 0.8–1.2 basicity (CaO/SiO2) when roasted at 1200–1250 °C, thereby decreasing the amount of liquid phase that formed initial deposits. XRD and SEM analyses of deposit simulants demonstrated that the addition of MgO was conducive to form magnesium magnetite and ferri-diopside, thereby avoiding the formation of hedenbergite with lower melting temperature. Moreover, the softening-melting performance and adhesivity tests confirmed that MgO had a positive effect on reducing liquid-phase deposition and inhibiting the adhesion of deposits on refractory bricks below 1250 °C. The above studies indicated that the addition of MgO helped to slow down the deposit formation of fluxed pellets prepared by coal-fired rotary kiln.

Effect of deposition time toward surface morphological and optical properties of silicon dioxide thin films on black silicon by liquid-phase deposition

Effect of deposition time toward surface morphological and optical properties of silicon dioxide thin films on black silicon by liquid-phase deposition

Effect of ZnO seed layer annealing temperature on the growth of ZnO nanorods and its catalytic application

This paper reports the effect of ZnO seed layer annealing temperature on the growth of ZnO nanorods. ZnO nanorods were grown on fluorine-tin oxide (FTO) substrate via simple and facile liquid phase deposition (LPD) at low temperature. High density homogeneous ZnO nanorods have successfully been synthesized directly on the substrate at 60 °C for 4 h reaction time. It was observed that average diameter and length of ZnO nanorod increased, when the annealing temperature increased from 300 °C to 500 °C. Field emission scanning electron microscope (FESEM) images reveal that by increasing the annealing temperature, the homogeneity, particle size, orientation and morphological shape of ZnO nanostructure have been modified. The photoluminescence (PL) spectra reveal the decrease in green emission as the annealing temperature was increased. The UV–Visible characterization confirms the decrease in the transmittance as the annealing temperature was increased.

Optimization of hydrolysis temperature in liquid phase deposition for TiO2 photocatalysis

TiO2 nanostructure could be produced at below 100 °C by means of liquid phase deposition (LPD), which is a green approach with low cost and low impact on the environment. The improvement of crystallinity is one of the main challenges toward efficient photocatalysis. Herein, we investigated the dependence of synthesis temperature on the crystal structure of TiO2 photocatalysts to provide higher photocatalytic efficiency. Scanning electron microscopy, X-ray diffraction, and Raman spectroscopy analysis confirmed the formation of waxberry-like TiO2 with an anatase phase with a synthetic temperature up to 80 °C. Both reaction temperature and time are found to dictate the crystallinity, structure, and size of the products, which could be attributed to the hydrolysis of a precursor (ammonium hexafluoro titanate), as well as the aggregation and coagulation of primary particles. The product synthesized at 70 °C for 3 h exhibited higher crystallinity, which led to higher photocatalytic efficiency observed based on the decomposition of methylene blue.

Evaluation of the long-term anticorrosion behavior of (OCP + Ca-P)/MAO coated magnesium in simulated body fluids

Magnesium has attracted wide interest as a biodegradable metal implant. However, the weak corrosion resistance restricts its practical applications. A CaP sealing coating was prepared on the surface of microarc-oxidation coating (MAO)-coated Mg via a liquid-phase deposition. The liquid-phase deposition time affects not only the microstructure and phase composition of CaP coating, but also the long-term anti-corrosion and biodegradability of the MAO coated Mg. The phase composition of the CaP coating evolves from octacalcium phosphate (OCP) + Ca-P compound (Mg-containing) to Ca2.86Mg0.14(PO4)2 with increasing deposition temperature. Mg with (OCP + Ca-P compound)/MAO coating exhibits outstanding anti-corrosion property during 60 days of immersion in simulated body fluids. Meanwhile, the OCP + Ca-P compound coating can facilitate the deposition of osteoconductive minerals, i.e., the hydroxyapatite layer, on the OCP coating during immersion in SBF solution. A rational model for the anticorrosion procedure of the Mg with (OCP + Ca-P)/MAO coating in SBF solution for a long-time immersion is proposed.