Weak Alkaline Solution Research Articles

Corrosion behavior of Laves precipitates in FeCrAl-1Nb alloy at 290 °C and 7 MPa: The size effect and critical role of pH

The corrosion behavior of Laves precipitates in FeCrAl-1Nb alloy was investigated in four different deoxygenated solutions at 290 °C and 7 MPa. The Laves precipitates exhibit potential size effect during corrosion in a weak alkaline solution: the microscale precipitates undergo oxidation with amorphization and element dissolution, and these phenomena are not observed in nanoscale precipitates. The corrosion of nanoscale precipitates is less insensitive to slight changes in pH; however, micro-galvanic corrosion was observed between some nanoscale precipitates and the ferrite phase. Deuterium isotope labeling experiments observed hydrogen enrichment in some oxidized precipitates.

Fluorinated PAMAM-Arginine Carrier Prodrugs for pH-Sensitive Sustained Ibuprofen Delivery

ObjectiveThe development of an efficient, multifunctional drug delivery system overcoming different obstacles generally associated with drug formulations, including the poor accumulation of the active principle in the target site and its sustained release for prolonged time.MethodsOur study proposes the development of a fluorinated poly(amidoamine) (PAMAM) carrier prodrug combining drug release boosted in alkaline environments with a possible implementation in 19F MRI applications. In particular, we functionalized the terminal primary amines of PAMAM G2 and G4 through an ad hoc designed fluorinated ibuprofen-arginine Michael acceptor to obtain multifunctional ibuprofen-PAMAM-Arg conjugates.ResultsThese carriers demonstrated pH-dependent and sustained ibuprofen release for more than 5 days. This advantage was observed in both weak alkaline and physiological buffer solutions, allowing to overcome the limits associated to the burst release from similar fluorinated Arg-PAMAM dendrimers with ibuprofen physically encapsulated.ConclusionThese findings, coupled to the high biocompatibility of the system, suggest a potential synergistic biomedical application of our conjugates, serving as vehicles for drug delivery and as 19F magnetic resonance imaging contrast agents.

INFLUENCE OF ACID-BASE ACTIVATION ON CHANGES IN THE SURFACE PROPERTIES OF ALUMINOSILICATES

The effect of activation with weak acids and weakly alkaline solutions on the change in the surface properties of natural materials, which are aluminosilicates, has been investigated. The use of natural sorbents has a wide range of practical applications, which actualizes the study of their physicochemical and adsorption properties. A comparative study of the native material - the flask of the Astrakhan region, as well as the material activated with a 6% solution of oxalic acid, and then activated with a solution of sodium bicarbonate of the same concentration was carried out. The study of the morphology of the obtained samples indicates a more developed surface of the native material. The presence of isometric open pores in the native material confirms the clay component. Moreover, activation with a weak acid leads to a decrease in the pore size and specific surface area by a factor of 1.3, and further exposure to a weakly alkaline solution causes the surface to become uniform (it decreases by a factor of 1.5 from the initial value). The results obtained are confirmed by the BET method. The specific surface of the material and porosity decrease by 23% upon activation with a weak acid and by 31% upon further activation with a weak alkaline solution, which also confirms the destruction of the structure. The data obtained on the change in the chemical composition during the activation process make it possible to classify the natural material as belonging to the class of montmorillonite (SiO2: 30 – 33%), and the presence of a clay component (Al2O3: 2 – 3%) indicates the destruction of the material upon activation not only with strong acids, but also with weak ones. A change in the Si/Al ratio, extraction of metal ions in the exchange region does not lead to the expected increase in the specific surface area and pore volume, which can be explained by surface recrystallization. The study of the acid-base characteristics of the surface by the pKa method indicates a wide variety of active centers on the surface and is inhomogeneous in nature, with the advantage of the cationic function. Upon activation, an increase in the anionic function of the surface is observed.

Hydrogen production from Al catalytic hydrolysis using highly active Nano composite CaO-AlOOH/Graphene oxide (GO) catalysts derived from eggshell and cauliflower stems

The hydrolysis of lightweight Al-based materials to produce hydrogen is a promising technology for compact hydrogen fuel cell production. However, developing nanostructures on a wide scale and at a low cost remains a major challenge. Herein, the high catalytic effect of CaO-γ-AlOOH/Graphene Oxide (GO) Nanocomposites (NCs) catalyst for hydrogen generation from Al and H2O reaction is discussed. These γ-phase aluminum oxyhydroxide Nanorods (NRs) (γ-AlOOH) on GO were synthesized through a simple hydrothermal method. High crystalline CaO-γ-AlOOH/GO NCs prepared bya mechanical grainingwithCaO nanoparticles (NPs). Experimental results show that small amounts of GO and CaO composite into γ-AlOOH NRs have high catalytic performance on the Al/H2O reaction for hydrogen generation at 25℃. In the catalysis process, the presence of oxygen on the catalyst surface promotes the formation of hydroxyl groups through a chemisorption process, further enhancing the catalytic activity. Because of high OH– concentrations in the local domain with a rise in the amount of Al(OH)3 precipitate byproduct, Al corrodes quickly and totally in a weak alkaline solution (pH < 8) after several contributions of Al batches. Accordingly, this research developed an excellent prediction for considering the Al reaction rate with H2O using CaO and/or GO composite crystalline γ-AlOOH catalyst.

The effect of sodium citrate on the photolytic reaction of catechin following the addition of aluminum chloride under alkaline conditions

Tea has an abundance of aluminum and catechins. As a food additive, citrate is often added to tea. An aluminum ionic species, including its amphoteric Al3+, can be either neutral or negatively charged and exist as intermediates simultaneously in weak alkaline solutions. This study is undertaken to investigate the photolytic processes of 290 mg/L catechin hydrate (CH) upon the addition of 133 mg/L AlCl3 (CHA) and CHA in the presence of 294 mg/L sodium citrate dihydrate (CHAS) to determine the structural changes in catechin and analyze its photoproducts after blue light irradiation at 20 W/m2 in H2O at pH 8 (BLIH) via high-performance liquid chromatography equipped with a diode array detector and mass spectrometry (HPLC-DAD-MS) system. The photolytic effect of blue light on sodium citrate was also determined. When CH is treated with BLIH, A-type and B-type proanthocyanidin dimers, AtPA and BtPA, respectively, are formed by a photochemically driven redox reaction. Relative percentages of the resultant catechin are 46.3, 98.1, and 46.9 for CH, CHA, and CHAS, respectively, after BLIH treatment, suggesting that the photolysis of catechin after BLIH is suppressed by AlCl3 and that sodium citrate restores the process of the catechin-aluminum system under BLIH in alkaline conditions. The addition of AlCl3 reduces the generation of proanthocyanidins during the photolysis of catechin after the dimeric molecule is disconnected by AlCl3, which acts as a catalyst after BLIH. However, under the same conditions, the addition of sodium citrate inhibits the catalytic capacity of AlCl3, and more proanthocyanidins are generated by the catechin-aluminum system under BLIH. Sodium citrate features an inherent reducing potential to maintain the photostability of the catechin-aluminum system and inhibits the catalysis of aluminum ions in alkaline conditions under BLIH.

Improvement of Eucalyptus urophylla wood permeability via urea treatment

To increase the loading amount of modifier in wood, a simple and universal approach was developed to improve its permeability. The generated pores in wood can be backfilled with modifiers, thereby improving the function of wood. This study aimed to improve the permeability of Eucalyptus urophylla wood using a urea solution. The wood was treated under different conditions, including urea concentration, treatment duration, and temperature, and the wood permeability before and after treatment was measured using water absorption as an indicator. The treatment temperature and solution concentration had considerable effects on the water absorption capacity of the treated wood. The treatment of eucalyptus wood with a 5% urea solution for 12 h, under normal pressure, resulted in the optimal effect; water absorption reached 40%, which was 78.9% higher than that of the untreated eucalyptus. Fourier-transform infrared spectroscopy, component analysis, and BET analysis were performed to examine the mechanism underlying the effect of urea treatment on eucalyptus, which is as follows: a weak alkaline solution can dissolve the internal components of wood, namely, hemicellulose, lignin, and alcohol-benzene, which leads to the destruction of the microstructure of the wood and increases the number of micropores and mesopores in the wood.

Pitting corrosion behavior of X70 steel in weakly alkaline solution under dynamic DC interference

Stray current discharged into the soil when subway trains operate will lead to fluctuation in the pipe-soil potential, which causes severe corrosion. In this work, the pitting corrosion behavior of X70 steel in a weakly alkaline simulated soil solution under different potential fluctuation ranges was studied. The influence of the fluctuation of the pipe-to-soil potential on the passivation film and pitting corrosion was studied using electrochemical measurement and surface characterization. X70 steel has passivation characteristics in the weakly alkaline solution. The passivation film is in a dynamic process of continuous growth or growth-dissolution due to the alternating polarization. The critical factor in inducing pitting corrosion is the failure to produce stable and dense passivation film or the instantaneous polarization potential exceeding the range of passivation potential. The passivation film's density determines the pitting's initiation and development trend. It is preliminarily found that the charge transfer resistance at the initiation stage of pitting has a good exponential function relationship with the pitting rate at the stable development stage, which is of great significance for the qualitative evaluation of the pitting rate.

Mussel – Inspired biosorbent combined with graphene oxide for removal of organic pollutants from aqueous solutions

In this work, we develop a mussel-inspired biosorbent combined with graphene oxide for removal of organic dyes in water sources. The composite was prepared via self-polymerization of dopamine in weak alkaline solution containing graphene oxide at ambient condition. Morphological and structural studies revealed that polydopamine has gradually grown to cover the surface of graphene oxide flakes, partially reduced these flakes, and somehow form many grains (size around 20 nm) on the flakes instead of making very large aggregates as usual. The mass ratio between two components of the composite was also investigated to find the optimal one which provides enough surface area (20 m2.g−1) and maintain adhesive sites in order to ensure high-efficiency removal of organic molecules. The adsorption kinetics and isotherms of as-prepared adsorbent towards methylene blue were found to fit well with pseudo-first order kinetics model and Langmuir isotherm. The maximum adsorption capacity (qm) and Langmuir constant (kL) were estimated to be 270 mg.g−1 and 0.49 L. mg−1. The as-prepared bio-sorbent is very promising for remediation of water sources contaminated with cationic organic molecules and heavy metal ions.

Deep separation of critical metals of Mo and Re from waste solution by stepwise precipitation flotation: Selective chelation underlying separation mechanism

Conventional selective precipitation method has disadvantage in the low-efficiency filtration of fine precipitated particles during the treatment of waste solutions. To overcome this shortcoming, a stepwise precipitation flotation process was proposed to deeply separate Mo and Re from Mo-Re mixing waste solution with low concentrations in this work. Chelating agents are critical for the selective separation of Mo and Re. Experimental results show that the rhenate can be firstly separated from mixing solution by the synergistic effect of cetyl trimethyl ammonium bromide (CTAB) and dodecyl trimethyl ammonium bromide (DTAB). In the weak alkaline solutions with pH range of 6–10, CTAB shows a stronger competitive adsorption capacity with rhenate than molybdate through electrostatic interactions and coordination reactions. Meanwhile, DTAB has a great inhibition effect on the chelation of molybdate by CTAB in this pH range, which can further enhance the selective chelation of rhenate by CTAB. After Re separation, molybdate can be further recovered by CTAB from the residual solution with pH range of 3–5. In this pH range, Mo mainly exists in the form of isopolymolybdates acid, and molybdate shows a stronger competitive adsorption ability with CTAB than DTAB. Molybdate reacts with CTAB to form precipitate, and the fine precipitated particles are readily separated via flotation. The turbidity of the residual liquid after flotation is less than 5 NTU, meeting the wastewater discharge standard. In the Re precipitation flotation procedure, the comprehensive efficiencies of Re and Mo are 96.6% and 0.14% under the main conditions of temperature of 25°C, n(CTAB)/n(Re) molar ratio of 2:1, n(DTAB)/n(CTAB) molar ratio of 2:1, and pH of 6. In the further Mo flotation separation, Mo comprehensive recovery of 97.9% is achieved by using CTAB and KH2PO4 as chelation agent and flocculant, respectively. The technological parameters of the conventional selective precipitation method and precipitation flotation method as well as the Mo and Re distributions in these two processes were compared in this study. Moreover, compared with the conventional selective precipitation method using inorganic precipitators, the precipitation flotation process shows a unique advantage in the easy purification of obtained products due to the utilization of organic agents.

Electrospun nanofibres containing Zn-MOF for electrochemiluminescent determination of fenpropathrin residues in fruit juices

In this work, Zn-MOF electrospun nanofibres (Zn-MOF NFs), CdTe and Au@Pt-rGo were applied to Ru(bpy)32+/tri-n-propylamine electrochemiluminescence (ECL) system. And a novel ECL sensor for the determination of fenpropathrin was constructed for the first time. Due to the large surface area and pores, Zn-MOF NFs can both carry CdTe and Au@Pt-rGo and promote luminescence by facilitating electron transfer and reducing electron transport paths. CdTe participated in the luminescence reaction and improved the system’s sensitivity together with Ru(bpy)32+. Au@Pt-rGo can promote electron transport in the system. Under the synergistic effect of the three, the ECL sensor had achieved satisfactory results in weak alkaline solution. The constructed ECL sensor can detect fenpropathrin in the range of 4 × 10−11–4 × 10−6 M, and the detection limit was 1.33 × 10−11 M (S/N = 3). It can be used to detect fenpropathrin in juice samples, which provided a new idea for determining fenpropathrin.

Fabrication of a robust superhydrophobic coating from the aqueous self-assembly of perfluoropolyether-based triblock copolymers

Five types of poly(hydroxyethyl methacrylate)m-perfluoropolyether-poly(hydroxyethyl methacrylate)m triblock copolymers (HFHm) with different poly(hydroxyethyl methacrylate) chain lengths were synthesized successfully. The as-synthesized HFHm can self-assemble into micelles in water with perfluoropolyether core surrounded by poly(hydroxyethyl methacrylate) corona under a dilute concentration. By casting the mixture of the HFHm micelles in water, hydrophilic silica nanoparticles and hydrophilic polyisocyanates as a cross-linking agent, a robust superhydrophobic surface can be obtained on smooth substrates. The addition of silica nanoparticles and polyisocyanates enhances the surface roughness and mechanical durability of the coatings. Due to the high surface roughness (Ra = 889 nm) and the high surface fluorine content (41.9 wt%), the cross-linked HFHm superhydrophobic coating can reach a water contact angle of 157.8 ± 0.7° and a water sliding angle of 3.5 ± 0.6°. After 30 abrasion cycles or immersion for 22 h in strong acid (pH 2) and weak alkaline (pH 9) solutions, the coating still maintains its superhydrophobicity. These phenomena indicate that the HFHm can be used as a kind of environment-friendly coatings with superhydrophobicity.

Evaluation of aroma characteristics in grass carp mince as affected by different washing processes using an E-nose, HS-SPME-GC-MS, HS-GC-IMS, and sensory analysis

The aroma characteristics of grass carp mince washed in four processes were analyzed via electronic nose (E-nose), headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), and sensory analysis techniques. Significant differences were revealed in the E-nose and sensory analysis results of the aroma characteristics of grass carp mince samples washed via different washing processes, while fifty-seven volatile compounds (thirteen aldehydes, eighteen alcohols, two ketones, eighteen hydrocarbons, two aromatic compounds, one furan, and two other compounds) and twenty volatile compounds (five aldehydes, four ketones, six alcohols, four esters, and one acid) were identified via HS-SPME-GC-MS and HS-GC-IMS of the Raw and washed grass carp mince samples, respectively. All these techniques revealed that the types and relative contents of volatile compounds in the grass carp mince decreased significantly and differently after each of the four washing processes. Moreover, compared with the water and saline solution washing processes, washing with weak alkaline solution processes exhibited the most significant removal effect on the volatile compounds of grass carp mince. Besides, the sensory analysis results also showed that weak alkaline solution washing processes (washing twice with pure water and once with 0.3% sodium bicarbonate solution) may be most effective in removing fishy off-odor compounds and contributing to a better overall aroma profile in grass carp mince. The findings of this study may provide some basic knowledge for the rational screening of washing methods in the production of high-quality grass carp surimi.

Measurement of the concentration of hydrogen ions in the mucous membranes of the upper respiratory tract. Mittermaier and Marchionini (Zeitschrift f. Hals-NasenOhren-Heilkunde, 1928. B. 20)

Mittermaier and Marchionini (Zeitschrift f. Hals-NasenOhren-Heilkunde, 1928. B. 20) investigated the state of the mucous membranes and secretions in acute inflammation of the paranasal sinuses, and found a displacement of Pu towards the acidic reaction; so, with acute inflammation of the frontal sinus, Rn 6.63; with severe acute and purulent sinusitis Pn 6.4. With the transition of an acute process into a chronic one, the pH also shifts towards alkalinity; so. polypoidly degenerated mucosa in chronic sinusitis gave Pn = 7.9; These studies have, in addition to the theoretical and practical result, the widely practiced washing of the inflamed sinuses with various solutions receive certain indications, namely: in acute inflammations, the lavages should be performed with weakly alkaline solutions, and for chronic inflammations, with weakly acidic solutions.

Improved clearing method contributes to deep imaging of plant organs

Tissue clearing methods are increasingly essential for the microscopic observation of internal tissues of thick biological organs. We previously developed TOMEI, a clearing method for plant tissues; however, it could not entirely remove chlorophylls nor reduce the fluorescent signal of fluorescent proteins. Here, we developed an improved TOMEI method (iTOMEI) to overcome these limitations. First, a caprylyl sulfobetaine was determined to efficiently remove chlorophylls from Arabidopsis thaliana seedlings without GFP quenching. Next, a weak alkaline solution restored GFP fluorescence, which was mainly lost during fixation, and an iohexol solution with a high refractive index increased sample transparency. These procedures were integrated to form iTOMEI. iTOMEI enables the detection of much brighter fluorescence than previous methods in tissues of A. thaliana, Oryza sativa, and Marchantia polymorpha. Moreover, a mouse brain was also efficiently cleared by the iTOMEI-Brain method within 48 h, and strong fluorescent signals were detected in the cleared brain.

Experimental Study on Dynamic Compression Mechanics of Sandstone after Coupled Alkali‐Chemical‐Dynamic Interaction

For the purpose of analyzing the effect of the alkaline solutions on the mechanical property of sandstone impact compression, the sandstone specimens of coal mine roadway were corroded in NaOH solution with pH 7 (neutral pure water solution) and pH = 8, 9, 10, 11, and 12 for 28 d, followed by dynamic compression tests using a separated Hopkinson compression bar test device, and the microstructural changes of the specimens were measured by SEM electron microscope scanning equipment. The studies indicate that the degree of damage to the dynamic properties of a sandstone specimen is tightly correlated with the variation of the pH value of the corrosion solution. The corrosion deterioration effect of the strong alkaline solution is most obvious, followed by the weak alkaline solution, and the mechanical properties of the sandstone are relatively stable under a neutral solution. The dynamic compressive strength and dynamic modulus of elasticity of specimens decrease as a quadratic and cubic function, respectively, with the rising pH of the solution. The dynamic peak strain and average strain rate tend to increase with the increase in pH, and they are larger than those of the uncorroded specimens. As the pH of the solution rises, the impact damage of the sandstone specimens intensifies, and the average particle size of the fragments tends to decrease in a quadratic polynomial.

Biomimetic mineralization and characterization of hierarchically structured hydrated magnesium carbonates: The effects of sodium alginate

Recently, CO2 mineralization involving magnesium salt provides a feasible way for carbon sequestration. The produced hydrated magnesium carbonates (HMCs) can be used as functional materials and will bring huge economic benefits. Inspired by the mineralization in biological organisms, the indirect CO2 mineralization process involving NH4HCO3-MgCl2 in the presence of sodium alginate (SA) was systematically investigated. XRD, SEM, FTIR, TG and XPS were used to characterize the crystal phase, morphology, structure and surface of HMCs. By the regulation of temperature, HMCs with a complex hierarchical structure were successfully synthesized, i.e., sea urchin-like nesquehonite assembled by nanorods and 3D spiderweb-like hydromagnesite assembled by nanosheets. The presence of SA inhibits the phase transition from nesquehonite to hydromagnesite, and the inhibitory effect increases as the concentration of SA increases. By decreasing the molar ratio of Mg2+/HCO3−, the shape of nesquehonite particle changes from a sphere to an ellipsoid or a gourd. The spherical structure of nesquehonite is destroyed in a weak alkaline solution and the crystalline product is flower-like hydromagnesite in a strong alkaline solution. The decomposition process of HMCs is composed of dehydration (or dehydration and dehydroxylation) stage and decarbonation stage. XPS results for nesquehonite and hydromagnesite are quite different due to their different surface structure. This study will provide insights into the preparation of hierarchically structured HMCs by indirect CO2 mineralization and promote added values of HMCs by biomimetic mineralization method.

Selective leaching of vanadium from vanadium-molybdenum residue based on carbonation transformation at ambient temperature

A novel process is proposed to selectively leach vanadium and separate molybdenum from the vanadium-molybdenum residue (VMR) in the weakly alkaline solution, which is built on carbonation leaching. The optimal leaching conditions of the 16 wt% sodium carbonate, leaching temperature of 25℃, leaching time of 4 h, and liquid-solid ratio of 1.5:1 mL/g were systematically researched. And the leaching efficiency of vanadium and molybdenum were 86.85% and 7.73%. The equilibrium constant K was calculated from the solubility product Ksp of the calcium-based compounds, and it was found that calcium vanadate was considerably preferred to the transformation of calcium molybdate and sodium carbonate. Calcium vanadate was simpler to dissolve than calcium molybdate, simultaneously vanadium and molybdenum were separated. XRD and XPS analysis confirmed that vanadium was leached while molybdenum remained in the leaching residue. One of the reasons why a small amount of vanadium was not leached was that calcium sulfate participated in the carbonation transformation and consumed sodium carbonate. The other reason is that part of V(III) stably existed in the (Cr, Fe)2O3 spinel. The whole process of carbonation leaching is carried out at ambient temperature, which is a process of clean separation of vanadium and molybdenum.

Selective Separation and Analysis of Catecholamines in Urine Based on Magnetic Solid Phase Extraction by Mercaptophenylboronic Acid Functionalized Fe3O4-NH2@Au Magnetic Nanoparticles Coupled with HPLC

A novel magnetic solid phase extraction based on mercaptophenylboronic acid (MPBA)-functionalized Fe3O4-NH2@Au nanomaterial (Fe3O4-NH2@Au-MPBA) was developed for selective separation and enrichment of catecholamines (including dopamine, norepinephrine and adrenaline). Fe3O4-NH2@Au-MPBA nanoparticles were achieved by self-assembly-anchoring MPBA molecules on the surface of Fe3O4-NH2@Au nanocomposites, which were synthesized via a facial ultrasonic auxiliary in situ reduction process. The interaction between cis-diol from catecholamines and boronic acid was reversible and could be flexibly controlled by adjusting pH value. The catecholamines could be quickly adsorbed by Fe3O4-NH2@Au-MPBA in weak alkaline solution (pH 8.0–9.0) and subsequently released in acid solution (pH 1.0–2.0). The process of adsorption and dissociation was very fast. Furthermore, the three catecholamines could be detected in urine from children by high performance liquid chromatography (HPLC) with electrochemical detector. Under optimal conditions, norepinephrine (NE), epinephrine (EP) and dopamine (DA) were separated very well from internal standard and exhibited a good linearity in the range of 2.5–500.0 ng mL−1, with correlation coefficients of r2 &gt; 0.9907. Limits of detection (LOD) (signal to noise = 3) were 0.39, 0.27 and 0.60 ng mL−1 for NE, EP and DA, respectively. Recoveries for the spiked catecholamines were in the range of 85.4–105.2% with the relative standard deviation (RSD) &lt; 11.5%.

Dopamine-assisted co-deposition of hydroxyapatite-functionalised nanoparticles of polydopamine on implant surfaces to promote osteogenesis in environments with high ROS levels

Environments with high reactive oxygen species (ROS) levels, which are common in patients with diseases such as diabetes, periodontitis, and osteoporosis, impair the osseointegration of implants. To address this issue, by using a one-pot dopamine-assisted co-deposition method, we constructed a three-dimensional coating of hydroxyapatite-functionalised nanoparticles of polydopamine (HA/nPDAs) on implant surfaces, where polydopamine is designed to protect cells via scavenging excessive ROS and HA facilitates osteogenesis. First, nanoparticles of polydopamine (nPDAs) were prepared by self-polymerization and assembly of dopamine under alkaline conditions, and HA/nPDAs were obtained by incubating nPDAs in simulated body fluid (SBF) due to metal chelation and ionic interactions triggered by the catechol moieties of PDA. Thereafter, HA/nPDAs with thickness of ~4 μm were constructed on titanium surfaces by immersing titanium discs in a weak alkaline solution of HA/nPDAs and dopamine through interface interactions driven by catechol chemistry. The properties of coatings (e.g., thickness, composition, hydrophilia and morphology) can be controlled by preparation conditions such as mineralization time and reactant concentration. The coatings display efficient ROS-scavenging ability, promote cell proliferation, and upregulate the activity of alkaline phosphatase and the expression of osteogenesis-related genes in environments with high or normal ROS levels, demonstrating the great promise of such coatings for osseointegration promotion, especially in the state of high ROS in diseases. This study provides a facile, efficient, mild, and universal strategy in engineering functional surfaces on any substrates for diversified applications by simple variation of co-deposited components, through taking advantages of versatile catechol chemistry and nanoparticles with stereo structure and great specific surface area.

Magnetic Properties of Electrodeposited Cobalt-Platinum (CoPt) and Cobalt-Platinum-Phosphide (CoPtP) Thin Films.

CoPt and CoPtP thin films were synthesized using direct current (DC) aqueous electrodeposition from weak alkaline solutions. The basic plating solutions of binary CoPt thin films consisted of cobalt pyrophosphate [Co2P2O7] and chloroplatinic acid [H2PtCl6]. Various amounts of sodium hypophosphite [NaH2PO2] was added to deposit ternary CoPtP thin films. The film composition was adjusted by varying the several electrodeposition parameters including electrolyte composition, solution pH, and current density and correlated to their microstructure and magnetic property (i.e. coercivity and squareness). For the binary CoPt thin films, the maximum coercivities [in-plane coercivity (Hc,//) = ∼1,600 Oe, and perpendicular coercivity (Hc,⊥) = ∼2,500 Oe] were obtained from electrolytes containing 0.01 M H2PtCl6 + 0.04 M Co2P2O7 at current density (CD) of 7.5 mA cm−2. In the case of ternary CoPtP electrodeposits, the maximum coercivities (Hc,// = ∼2,600 Oe, and Hc,⊥ = ∼3,800 Oe) were achieved from baths containing 0.015 M H2PtCl6, 0.07 M Co2P2O7, 0.8 M NaH2PO2 at CD of 7.5 mA cm− 2 and solution pH 9. It was suggested that microstructure and magnetic properties are affected not only by the type of substrate but also by chemical compositions and electrodeposition conditions.