Cathodic Electrophoretic Deposition Research Articles

Piezoelectric barium titanate/hydroxyapatite composite coatings on Ti-6Al-4V alloy via electrophoretic deposition

Electrophoretic deposition (EPD) is a widely accepted, cost-effective and simple method to obtain conformal coatings of dense nanoparticles via application of a DC voltage. This paper reports the physical and mechanical properties of nanostructured barium titanate/hydroxyapatite (BT/HA) ceramic composites coated onto Ti-6Al-4V alloy via cathodic EPD in various ratios of 40:60, 50:50 and 60:40 (HB4, HB5 and HB6) respectively. Homogenous BT/HA coatings were obtained at a notably low voltage of 10 V. The crystallinity and phase analysis confirmed the formation of tetragonal phase of BT indicating the piezoelectric property. HB6 exhibits maximum piezoelectric coefficient (d33) of 159 pC/N and Vicker's hardness of 242.31 HV. The cross-sectional electron micrographs show well connected and homogeneous coatings with increasing amounts of BT. Human mesenchymal stem cell lines were utilized in biocompatibility experiments, which revealed that HB composites had greater viability of HW-MSCs cells than pure BT, with HB6 exhibiting a maximum cell viability of more than 90 %.

The Effect of Marginal Zn2+ Excess Released from Titanium Coating on Differentiation of Human Osteoblastic Cells.

Composite coatings based on chitosan and zinc nanoparticles (ZnNPs) were successfully produced on Ti13Zr13Nb substrates by cathodic electrophoretic deposition (EPD). The unfavorable phenomenon of water electrolysis-induced nonuniformity was reduced by applying a low voltage (20 V) and a short deposition time (1 min). Surface analysis (roughness and hydrophilicity) reveals the potential of these coatings for enhancing cell attachment and bone-implant integration. However, there is a concern about adhesion and strength; therefore, incorporating ZnNPs shows promise for enhancing mechanical properties, suggesting opportunities for further optimization of the process. The aim of this work was to investigate whether Zn2+ released from coating yields overt cellular impairment. hFOB1.19 osteoblastic cells were used as a model in this study. A subtoxic, 0.125 mmol/L, Zn concentration did not cause significant negative changes in cultured osteoblastic cells, as there was no significant change in their viability and their mitochondrial metabolism. Moreover, the alkaline phosphatase and lactate dehydrogenase activities were aggravated. However, a high, over 0.175 mmol/L, Zn2+ concentration caused total cell death. This was caused by the inhibition of mitochondrial enzymes' activities. Our data indicate that composite coatings releasing Zn2+ may be used as the differentiating factor toward osteoblastic cells.

Strategies for alkali-free synthesis, surface modification, and electrophoretic deposition of composite films for biomedical applications

This investigation addresses increasing interest in composites for biomedical applications and advanced methods for their synthesis and electrophoretic deposition (EPD). The feasibility of preparation of hydroxyapatite (HA), titania and zirconia particles using branched polyethylenimine polymer (BPEI) or L-arginine amino acid as organic alkalizers is demonstrated. In this new approach, BPEI and L-arginine are used as alkalizers-capping agents instead of inorganic alkalis. The use of BPEI facilitates synthesis of HA nanorods with reduced size. This approach opens an avenue for the fabrication of nanoparticles of other functional inorganic materials using alkalizers-capping agents. It offers advantages of simple procedure, environmental benefits and improved control of particle size. Composite films are obtained by cathodic EPD using linear polyethylenimine (LPEI) as a charging and film-forming agent. A conceptually new approach is developed for anodic EPD of alginic acid polymer (AlgH) and composite films containing drug molecules in AlgH matrix. This strategy involves the use of L-arginine as an alkalizer for solubilization of drugs, which exhibit poor solubility in water. AlgH and drug molecules are solubilized in water and deposited by anodic EPD. Testing results confirm the fabrication of composite films, containing drug molecules. This method allows reduced gas evolution at the electrode, elimination of film porosity, improved stabilization of bioceramic particles in polymer solutions and facilitates composite film formation from stable suspensions. The deposition methods developed in this investigation can be used for deposition of other cationic and anionic polymers and their co-EPD with bioceramics, drugs and other functional materials.

Corrosion behavior of ternary HA-NrGO-CS composite coatings via cathodic electrophoretic deposited on ZK60 Mg alloy combining with thermal annealing

In this paper, effect of various contents of chitosan (1.0, 1.5 and 2.0 wt%) on corrosion/degradation behavior of ternary HA-NrGO-CS prepared on ZK60 alloy substrates were investigated. The samples were prepared by combining cathodic electrophoretic deposition and thermal argon atmosphere annealing for 120 min at 200 °C to regulate corrosion and quick degradation of ZK60 Mg alloy surface. After immersion for 30 min, HA-NrGO-1.5CS coated sample exhibited highest |Z|0.1Hz value, trailed by the HA-NrGO-2.0CS, HA-NrGO-1.0CS and ZK60 alloy samples. After immersion for 2 days, |Z|0.1Hz values moved to higher Bode modulus for HA-NrGO-CS coated samples, indicating poles and defects were filled due to the formation of apatite layer on the HA-NrGO-CS surface. FT-IR and Raman spectra proved the successful doping of N atoms into the rGO nanosheet skeleton to form NrGO. The SEM images and EDS plane-scan results for the samples after immersion for 2 days verified the existence of an apatite layer. The experimental results indicated that the existence of CS, HA and NrGO in the composite coatings can regulate the pH values and supply a sustained release of Mg2+ ions and O2 due to the synergistic effect of the protonation/deprotonation of -NH2 groups in CS and the dissolution/recrystallization of HA. Furthermore, the production of MgO2 film can convert corrosion behavior of ZK60 alloy from pitting corrosion to uniform corrosion, which provided a potential strategy for bone biomedical applications.

GPC filler with dual functions of physical barrier and corrosion inhibition for corrosion protection enhancement of electrophoretic deposited epoxy coating

In this work, the synergistic effect of polyaniline (PANI) and Ce cations was utilized to develop a graphene oxide (GO) electrophoretic deposition (EPD) green epoxy (EP) coating with a physical barrier and corrosion inhibition. PANI and Ce cation not only form a protective layer with inhibition but also convert the negative charge of GO to a positive charge, thus satisfying the conditions of cathodic electrophoretic deposition (C-EPD). Anti-corrosion test results showed that the GO/PANI/Ce(NO3)3 (GPC)/EP composite coating has the highest impedance, with the impedance modulus at day 35 three orders of magnitude higher than that of the neat EP coating. The passivation film generated by the GPC inhibits large corrosion extensions; it produces a significant self-healing effect, as evidenced by the corrosion morphology, the XPS analysis, and the stable value of the impedance modulus. This work provides a new strategy for manufacturing high-performance electrophoretic epoxy coatings with self-healing properties.

Influences of Heat Treatment, Particle Arrangement, and Binder Addition on the Mechanical Robustness of Structurally Colored Coatings Formed with Monodisperse SiO2 Spheres

This article highlights the critical factors influencing the mechanical robustness of structurally colored coatings formed as arrays of monodisperse SiO2 particles. Various types of coatings can be fabricated using electrophoretic deposition (EPD) techniques. Anodic EPD generates coatings with colloidal crystalline structures, iridescent structural color, and noteworthy mechanical robustness owing to interparticle necking during heat treatment, even in the absence of binder additives. Conversely, coatings prepared via cathodic EPD exhibit noniridescent structural color and colloidal amorphous structure, with only marginally improved mechanical robustness after high‐temperature treatment. However, when Mg(OH)2 is codeposited during EPD in the coating, the resultant film exhibits strong adhesion between particles and the substrate—as evidenced by minimal peeling from the substrate even after ultrasonication for 6 h—owing to the binding effect of MgO, which is converted from Mg(OH)2 via heat treatment. The robustness of the film is not dictated by the size of the SiO2 particles, suggesting that this approach can be applied to structurally colored coatings of various colors. Consequently, the results suggest that EPD with the addition of a binder and heat treatment can be used to fabricate particle‐array‐type coatings with extremely high mechanical robustness.

Evaluation of Upscaling the Selective Electrophoretic Deposition of Reduced Graphene Oxide on Miniaturized Au Interdigital Electrodes from Chip-to Wafer-Level

Today’s novel materials challenge the research industry to enhance the performance and to reduce the power consumption of microchips as well as to develop new sensor principles. All this applies pressure on the investigation of new economical mass production technologies for the integration into standard process sequences or on top of state-of-the-art CMOS devices. Since the discovery of graphene in 2004, many different variations have been investigated, thus the number of publications of graphene-based content grew from a few in 2004 exponential to 1.2 million only in 2019, according to Google Scholar analysis. The deposition of graphene-based materials at wafer-level is still difficult to do economically on standard SEMI wafers up to 8” diameter. In this publication, the selective electrophoretic deposition (EPD) of reduced graphene oxide flakes (rGO) will be shown. This technique is a very promising deposition method for large scale fabrication. The EPD of rGO particles is the only known way to create 3D surface topologies for an enhanced sensing area of electrochemical sensor applications e.g. biosensors. The electrical and chemical properties of this novel material provides a broad range of applications for possible sensor solutions [1, 2]. Firstly, the deposition will be shown on chip scale to gain optimum parameters in suspension preparation and EPD deposition time/voltage for a uniform particle deposition over the sensor area. Shortcuts from particles between the transmission lines or co-deposition on reference electrodes have to be avoided. This leads to a high selectivity in rGO particle deposition on Au-structures. Afterwards designs and experiments have been made on array level and a proof of concept wafer-level deposition with a low volume suspension is demonstrated. In previous work, the adhesion of rGO on Au structures in electrochemical sensors with a liquid flow, showed a migration of the deposited particles with the friction of the liquid [3]. Therefore, standard separation of particle agglomeration or splitting of primary particles with ultra sonic sonotrodes are not sufficient to gain highly concentrated suspensions with homogenous target particle distributions (< 0,5µm ≤ 1µm ≥ 5µm). For this reason, a novel particle crushing preparation by ball milling is introduced and enhanced selectivity with an improved adhesion is demonstrated. A full process of the preparation of the colloidal suspension with the definition of target particle sizes with an optimum zeta potential will be provided and the cathodic electrophoretic deposition shown [4, 5]. For the evaluation of the deposition experiments, stereo microscopy is used to reveal the selectivity on the interdigital electrode (IDE) structures (sensor area) and scanning electron microscopy (SEM) analysis is used to characterize particle sizes and 3D topography, in terms of primary and secondary particles (agglomerates). For this study, IDE structures with 15 different geometry variations (3µm to 15µm lines and spaces) are used that were manufactured [6] to evaluate the rGO deposition on chip level. A novel multisensory array design with eight sensing areas are presented, combined with wafer-level deposition as a proof of concept on a 200mm wafer.

Cathodic electrophoretic deposition (EPD) of two-dimensional colloidal Ni(OH)2 and NiO nanosheets on carbon fibers (CF) for binder-free structural solid-state hybrid supercapacitor

The exponential growth of the renewable energies field and the increase of portable electric vehicles (EVs) demand a new generation of multifunctional efficient electrochemical energy storage devices (EESDs). In this work, binder-free hybrid battery-like electrodes were prepared by cathodic electrophoretic deposition (EPD). One-step (synthesis and deposition) processing of β-Ni(OH)2 was developed avoiding a previous calcination step to form NiO. The redox reaction (RR) contribution to the electrochemical performance of the hybrid electrodes was enhanced without influencing the mechanical properties of the CF substrate. Moreover, the sintering of the coated-CF under a high-vacuum atmosphere and the controlled mass deposition (<0.1 mg·cm−2) demonstrated to enhance the synergic effect of the redox reactions, ion diffusion (NiO) and the electrochemical double layer (CF) contributions. Thus, the hybrid electrodes in a half-cell configuration achieved remarkably high capacitance values (1161 F·g−1 at 2 A·g−1), while hybrid electrodes in a symmetric structural hybrid solid-state supercapacitor (HSSS) with an ionic liquid/resin structural solid-electrolyte reached a capacitance of 9.8 mF·g−1, a power and energy density of 3.5 mW·kg−1 and 1 mWh·kg−1 respectively and good electrochemical stability with a Columbic efficiency of 75 % at 0.8 mA·g−1.

Ti3C2Tx@polyaniline/epoxy coating based on cathodic electrophoretic deposition with effective corrosion inhibition effect for corrosion protection on P110 steel

Polyaniline-coated Ti3C2Tx particles (TPi) endowed the electrophoretic deposited epoxy coating with efficient physical shielding and corrosion inhibition capacities to improve the corrosion protection ability. Ti3C2Tx of few/single layers was prepared and TPi particles were synthesized by in-situ polymerization of polyaniline on Ti3C2Tx surface. Characterization results indicated the successful synthesis of TPi material. TPi/epoxy coating was prepared on P110 steel sheet through cathodic electrophoretic deposition method, and the protection ability was tested by electrochemical impedance spectroscopy (EIS) and saline immersion test. EIS results of the complete coating showed that impedance modulus at low frequency (0.01 Hz) of TP7 coating was 3.92 × 108 Ω cm2 after soaking for 20 d, which was higher than 2.82 × 106 Ω cm2 of neat epoxy coating (NEP), indicating better protection performance. The results of impedance spectrum of scratched coating showed that TP7 coating had obvious corrosion inhibition effect, which was attributed to the passivation effect of polyaniline to promote the conversion of loose corrosion products into dense layers. This research provided a new approach to apply Ti3C2Tx into the electrophoretic deposited epoxy coating with corrosion inhibition effect.

A Green and Fluorine‐Free Fabrication of 3D Self‐Supporting MXene by Combining Anodic Electrochemical In Situ Etching with Cathodic Electrophoretic Deposition for Electrocatalytic Hydrogen Evolution

AbstractThe work presents a green and fluorine‐free environmentally friendly two‐electrode system, which enables the direct fabrication of the corresponding 3D MXene electrodes by the synergistic combination of anodic electrochemical in situ Al etching from Mo2TiAlC2 MAX and cathodic electrophoretic deposition. In just several minutes, the Mo2TiC2 MXene can be deposited on the cathode plate (Pt foil or carbon cloth) without the need for organic large‐molecule intercalation agents or ultrasound treatment. This approach allows an efficient separation of MXene from the electrolyte, leading to a significant reduction in the quantity of waste acid generated by conventional acid etching processes. The electrochemically etched‐MXene can be uniformly and stably deposited onto carbon cloth (E‐MXene@CC), enabling its direct utilization as a 3D electrocatalyst for hydrogen evolution reaction (HER). This unique 3D E‐MXene@CC exhibits a moderate HER performance and outperforms most of the reported pure non‐precious MXene‐based catalysts in 0.5 m H2SO4. In order to clarify the catalytic mechanism, in situ Raman spectroscopy of 3D E‐MXene@CC reveals a significant down‐shift without observing any new bands when the HER potential shifts negatively, which can be attributed to H+ intercalation.

Evaluation of structural and corrosion behavior of chitosan/silver coating on Ti6Al4V/TiO2 nanotubular surface

Materials used in biomedical applications must have good bulk and surface properties. The main goal of this work is to create a multifunctional surface based on chitosan-coated Ag-loaded TiO2 nanotubes to assess their capacity in the corrosion resistance property. In the first phase, Ag-loaded TiO2 nanotubular surfaces with different weight percentages of silver were fabricated at a constant voltage of 2 V under varied time durations of 1 min, 2 min, and 3 min. In the second phase, cathodic electrophoretic deposition (EPD) was used to coat the samples with chitosan by applying 10 V for 5 min as a constant process parameter for coating all the samples. The composition and morphology features of in-house fabricated Ag-loaded TiO2 nanotubular surface with chitosan were studied by different techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffractometer (XRD), and Contact angle measurement. The corrosion resistance of the coated samples was assessed by using OCP, PDP, and EIS techniques. The results evidenced that chitosan-coated Ag-loaded (2 V 2 min) TiO2 nanotubular surface (TNT-Ag2.2/Ch) showed the best performance as a coating system when compared to an uncoated surface. Also, electrochemical corrosion studies showed better corrosion resistance for this coated sample. In this context, the chitosan that has been deposited serves as a protective barrier, facilitating the penetration of the physiological solution into the underlying metal surface. Overall, the TNT-Ag2.2/Ch coated sample showed 5 times better results when compared with icorr values. Finally, the newly developed chitosan-coated Ag-loaded TiO2 nanotubular surface improve the corrosion resistance of the polished Ti6Al4V alloy.

Cathodic electrophoretic deposited HA-rGO-ZnO ternary composite coatings on ZK60 magnesium alloy for enhanced corrosion stability

HA-rGO-ZnO ternary composite coatings were successfully prepared on ZK60 magnesium alloy using cathodic electrophoretic deposition method. XRD analysis proved the addition of ZnO nanoparticles induced a significantly reduced crystallinity in hydroxyapatite and the tensile strain values of HA-rGO-ZnO composite coatings gradually decreased as the content of ZnO increased. SEM analyses revealed that the HA and ZnO nanoparticles were anchored on rGO nanosheets and a closely-packed network of recrystallization needle-like ZnO and mineralization HA crystals was formed on the surface of HA-rGO-ZnO coated sample. The resulting composite coating exhibited a uniform and compact HA-rGO-16ZnO composite coating, with well adhered to the ZK60 magnesium alloy substrate. The HA-rGO-16ZnO coated sample exhibited the highest corrosion resistance with lowest icorr (1.12 × 10−6 A/cm2) and the highest Ecorr (−1.43 V/SCE) value when compared to HA-rGO-14ZnO and HA-rGO-18ZnO samples after immersion in a SBF for 10 min. Compared to HA-rGO-ZnO coated samples after 10 min of immersion in SBF, HA-rGO-ZnO coated samples after 3 days of immersion in SBF exhibited a remarkably improved corrosion resistance and rapid inducing of the apatite layer precipitated on the surface of the composite coatings. The microstructure and composition for the coated samples after 3 days of immersion in SBF also confirm that the presence of a apatite layer on the composite coatings. HA-rGO-18ZnO coated samples after 3 days of immersion in SBF showed the lowest icorr value, which indicating HA-rGO-18ZnO ternary composite coatings dramatically improved the formation ability of the apatite layer and led to an enhancement in the bioactivity. Accordingly, it is believed that the HA-rGO composite coating incorporated with ZnO will be a potential candidate for bone biomedical applications.

Vancomycin-loaded porous chitosan-pectin-hydroxyapatite nanocomposite coating on Ti6Al4V towards enhancing prosthesis antiinfection performance

Cathodic electrophoretic deposition (EPD) was used to fabricate novel porous chitosan/pectin/hydroxyapatite (CS/P/HA) nanocomposite coatings on Ti6Al4V substrates. Rietveld refinement results revealed variations in peak intensity, position, and width, reflecting structural changes resulting from the reduction of the applied voltage from 30 to 10 V. The deposits obtained at 10 V after 1 h of presedimentation exhibited a denser microstructure with narrow pore size distribution compared to the others. The wettability and adhesion strength of coated Ti6Al4V improved with increasing HA content. Release of antibiotic from the composite coating confirmed 40% initial burst release, 50% semi-steady release and 10% residual release. A thick and uniform porous apatite layer was formed on Ti6Al4V after 21 days of immersion in simulated body fluid (SBF). Therefore, CS/P/HA coated Ti6Al4V has the potential for practical antiinfection performance.

Simulation and Verification of the Direct Current Electric Field on Fabricating High Porosity f-MWCNTs Thin Films by Electrophoretic Deposition Technique.

Electrophoretic deposition (EPD) is the potential process in high porosity thin films' fabrication or complex surface coating for perovskite photovoltaics. Here, the electrostatic simulation is introduced to optimize the EPD cell design for the cathodic EPD process based on functionalized multiwalled carbon nanotubes (f-MWCNTs). The similarity between the thin film structure and the electric field simulation is evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM) results. The thin-film surface at the edge has a higher roughness (Ra) compared to the center position (16.48 > 10.26 nm). The f-MWCNTs at the edge position tend to be twisted and bent due to the torque of the electric field. The Raman results show that f-MWCNTs with low defect density are more easily to be positively charged and deposited on the ITO surface. The distribution of oxygen and aluminum atoms in the thin film reveals that the aluminum atoms tend to have adsorption/electrostatic attraction to the interlayer defect positions of f-MWCNTs without individually depositing onto the cathode. Finally, this study can reduce the cost and time for the scale-up process by optimizing the input parameters for the complete cathodic electrophoretic deposition process through electric field inspection.

Pulsed electrophoretic deposition of hybrid coatings from aqueous suspensions as surface functionalization and sealing technique of anodized AA2024. Part I: Morphological characterization, analysis of the interfacial interactions, and evaluation of pore impregnation of the anodic layer

In this two-part series, pulsed direct current for cathodic electrophoretic deposition (pulsed-CEPD) was studied as sealing technique of anodized AA2024 by depositing hybrid sol-gel films from aqueous suspensions. The coating was obtained using tetraethyl orthosilicate and hexadecyltrimethoxysilane as precursors and two pulse widths were used: 10 microseconds and 100 milliseconds. For comparison, continuous direct current for cathodic electrophoretic deposition was also performed. In this first article, it was developed a low-cost automated apparatus capable of creating pulsed fields using a commercial power supply. This was necessary since the automation system provided by the power supply manufacturer did not have a short enough response time able to create pulse widths in the order of microseconds. Field emission scanning electron microscopy (FESEM) and focused ion beam milling techniques were utilized to evaluate the surface morphology and interaction mechanisms in the interface anodic layer/film. Low voltage scanning transmission electron microscopy (STEM)-in-FESEM, and transmission electron microscopy (TEM) were used to evaluate the pore impregnation provided by pulsed-CEPD. Results demonstrated that the developed apparatus successfully created pulsed fields. FESEM micrographs of the anodic layer sealed by pulsed-CEPD showed that the shortest pulse provided the best films, likely due to the greater control of hydrogen bubbles generation and the promotion of a more regular deposition. Also, they revealed two interfacial interactions between the anodic layer and the film. STEM-in-FESEM images showed that the shortest pulse width provided greater pore impregnation by particles. This observation was confirmed by TEM, which demonstrated an incomplete pore impregnation for the longest pulse. Discussion regarding result interpretations is presented based on the generation and dissipation of H2(g) (considering the current interruption); on an alternative to the colloidal stability theory due to the presence of a pulsed field; and on the electrokinetic effects at the electrodes during pulsed-CEPD, that discusses how electroosmotic flow influences the deposition.

Cataphoretic deposition of an epoxy coating with the incorporation of Ti3C2Tx@Mg-Al layered double hydroxide for long-term active corrosion protection effect

Epoxy composite coating with active corrosion inhibition property was prepared through cathodic electrophoretic deposition with the incorporation of Ti3C2Tx@Mg-Al layered double hydroxides (LDH) hybrid material. Hydrothermal method was adopted to synthesize molybdate (MoO42−)-intercalated MgAl LDH, which was self-assembled on the surface of Ti3C2Tx MXene through electrostatic interaction to improve the zeta potential of the Ti3C2Tx surface to positive value. Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscope, scanning electron microscope, X-ray photoelectron spectroscopy, zeta (ζ) potentials test and uv-vis spectroscopic analysis results showed that MgAl LDH and Ti3C2Tx@Mg-Al LDH were successfully prepared and Ti3C2Tx@Mg-Al LDH had ion exchange property. The prepared LDH and Ti3C2Tx@Mg-Al LDH were added to electrophoretic paint as anti-corrosive additives. After deposition process of 150 V for 2 min on the P110 steel surface, composite coatings had thicknesses of ~110 μm. Electrophoretic deposition has advantages in controlling coating thickness than traditional spray method. Moreover, Ti3C2Tx@Mg-Al LDH additive endowed composite coating with active corrosion inhibition capacity through ions exchange property between corrosive medium Cl− and MoO42− in the MgAl LDH interlayer. Electrochemical impedance spectroscopy (EIS) test results showed that Ti3C2Tx@Mg-Al LDH/epoxy coating exhibited outstanding corrosion protection property. This research provides a new way of using Ti3C2Tx MXene in the cathodic electrophoretic paint to prepare active anti-corrosive coating.

Development and Investigation of Mesoporous Bioactive Glass/Zein Coatings Electrodeposited on Titanium Alloy for Biomedical Applications

The objective of the present work was the development of cathodic electrophoretic deposition (EPD) to obtain composite coatings of mesoporous sol–gel glass (MSGG) particles embedded in a zein matrix on Ti-13Nb-13Zr substrates. To deposit robust and repeatable coatings, a direct current EPD and pulsed direct current EPD as well as the deposition kinetics were investigated, including the deposition yield and deposition rate. The stability of the suspension was determined based on the zeta potential and conductivity. Macroscopically homogeneous coatings with a thickness of about 10 µm and various volume fractions of MSGG were subjected to further examination. Coatings were uniform, exhibiting open porosity and showing excellent adhesion to the substrates. Both zein and MSGG particles revealed an amorphous structure. The coated substrates demonstrated greater resistance to electrochemical corrosion in Ringer's electrolyte in comparison with the virgin (non-coated) substrate. The coatings showed high roughness and moderate hydrophilicity. The incubation of the coated substrates in concentrated 1.5 simulated body fluid (1.5SBF) showed the formation of carbonate hydroxyapatite. The composite coatings showed improved antibacterial properties against gram-negative E. coli and gram-positive S. aureus bacteria compared to pure zein coatings. Electrophoretic MSGG/zein composite coatings should be further investigated in terms of their osteoconductive behavior, to confirm their suitability for medical applications in orthopedics.

Electrophoretic deposition, microstructure and selected properties of nanocrystalline SnO2/Sr enriched bioactive glass/chitosan composite coatings on titanium

The presented study aimed to develop composite chitosan-based coatings with the addition of bioactive sol-gel glass enriched with Sr and potentially antimicrobial SnO2 nanoparticles on titanium substrates by cathodic electrophoretic deposition (EPD). The effect of suspension's chemical composition and pH level on their stability were investigated and adjusted to obtain macroscopically homogenous coatings. The electrosteric mechanism was responsible for coatings deposition. The dense coatings with excellent adhesion to the titanium and a well-developed surface including agglomerates of sol-gel glass and SnO2 particles were developed. It was shown that the roughness of the coatings was higher than for the underlying Ti substrate. All coatings demonstrated moderate wettability, 40 % higher in contact with water and 66 % higher in contact with non-polar liquid than for the pure Ti substrate. The surface free energy of the uncoated Ti substrates was about 32 % lower compared to the coated titanium. Furthermore, it was demonstrated that composite coatings containing SnO2 NPs, improve the electrochemical corrosion resistance of Ti substrates in Ringer's solution. Owing to the high adhesion strength of coatings, their morphology, wettability, and high corrosion resistance, they appear to be noteworthy in the future development of bioactive enhanced titanium surfaces with antibacterial properties.

Designable ultra-stable electrode surface engineering by the electrophoretic deposition of modified graphene oxide for rechargeable batteries

Electrode material surface protection via the two-dimensional structured graphene oxide (GO) is studied in our work for rechargeable batteries by the electrophoretic deposition (EPD). However, the large number of oxygen-containing groups on the surface and edge makes GO sheets negatively charged, which EPD can only be used for anode process. Thus, we apply p-phenylenediamine (PPD) to convert the surface of GO sheets to positive electricity and successfully achieve the cathodic EPD with modified GO. When, the cathode (eg. S, LiFePO4) and anode (eg. Li, Si) with the newfangled GO coating layers are employed in a working battery, the GO can be transformed into reduced graphene oxide (rGO) due to the in-situ electrochemical reduction. Fortunately, the rGO coating layers are acquired on the electrode surfaces, which the stability, adhesion, corrosion resistance, impact resistance have been greatly improved compared to other coating methods. Ultimately, taking advantage of this rGO coating by EDP to simultaneously realize the coating protections of the electrodes can provide alternative strategies to optimize the properties of rechargeable batteries.

Synthesis and property of room-temperature self-healable cathodic electrophoretic deposition coatings based on cationic waterborne polyurethane

Synthesis and property of room-temperature self-healable cathodic electrophoretic deposition coatings based on cationic waterborne polyurethane