Electrophoretic Deposition Process Parameters Research Articles

Electrophoretically deposited titanium and its alloys in biomedical engineering: Recent progress and remaining challenges.

Over the past decade, titanium implants have gained popularity as the number of performed implantation operations has significantly increased. There are a number of methods for modifying the surface of biomaterials, which are aimed at extending the life of titanium implants. The developments in this field in recent years have required a comprehensive discussion of all the properties of electrophoretically deposited coatings on titanium and its alloys, taking into account their bioactivity. The development that took place in this field in recent years required a comprehensive discussion of all the properties of coatings electrophoretically deposited on titanium and its alloys, with particular emphasis on their bioactivity. Herein, we attempt to assess the influence of the electrophoretic deposition (EPD) process parameters on these coatings' biological and mechanical properties. Particular attention has been addressed to the in-vitro and in-vivo studies conducted hitherto. We have seen an increased interest in using titanium alloys without the addition of toxic compounds and gaps in the EPD field such as the uncommon endeavors to develop a "Design of experiments" approach as well as the lack of assessment of the surface free energy and detailed topography of electrophoretically deposited coatings. The exact correlation of coating properties with EPD process parameters still seems explicitly not understood, necessitating more future investigations. Ipso facto, the exact mechanism of particle agglomeration and Hamaker's law need to be fathomable.

Liquid metal corrosion resistant LaPO4 coating with metallophobic characteristics fabricated on 316 stainless steel using electrophoretic deposition technique

A liquid metal corrosion (LMC) resistant and metallophobic lanthanum phosphate (LaPO 4 ) coating was prepared on SUS316 stainless steel using electrophoretic deposition (EPD) technique. A specific hierarchical surface structure was created on coating surface by adjusting EPD process parameters. LMC test was performed using three different metal melts, Al–Zn–Mg alloy, Mg–Al–Mn alloy, and pure Zinc. Results indicated that steel bare surface was severely attacked by all three melts. The mechanism of corrosion process was explained in each case. After coating, the LaPO 4 covered steel showed an excellent resistance against all three liquid metals. Besides, wetting of steel surface by liquid metals was strongly decreased by application of LaPO 4 surface coating. This can be attributed to the intrinsic metallophobic characteristic of LaPO 4 as well as the hierarchical surface structure developed on coating surface.

Electrophoretic deposition of carbon nanotubes: recent progress and remaining challenges

ABSTRACT Electrophoretic deposition (EPD) is a powerful technique to assemble carbon nanotube (CNT) coatings and composite films with controlled architectures. This comprehensive review of the EPD of CNTs and CNT-containing composites focuses on achievements within the last 15 years and ongoing challenges. Stable CNT suspensions are a pre-requisite for successful EPD and have been prepared by a variety of strategies, discussed here. The resulting film microstructure is determined by the initial feedstock, the suspension, and the EPD approach applied, as well as a variety of EPD processing parameters. Nanocomposites can be prepared via co-deposition, sequential deposition, or post-deposition treatments, to introduce metallic, ceramic or polymeric phases. There are numerous potential applications for both homogeneous and patterned CNT films, including as structural reinforcements for composites, as field emission, energy storage and conversion devices, as well as in biomedical applications. The advantages and disadvantages of EPD processing in these contexts are discussed.

Polymer-Based Electrophoretic Deposition of Nonwovens for Medical Applications: The Effect of Carrier Structure, Solution, and Process Parameters.

Hyaluronate and alginate are non-toxic and biocompatible polymers, which can be used for surface modification and functionalization of many kinds of materials. Electrophoretic deposition (EPD) has several advantages, including its versatility, simplicity, and ability to coat substrates with complex shapes, and is used for the creation of antimicrobial or hydrophobic coatings on metallic biomaterials, among other applications. However, its utilization for applying biopolymer layers on textiles is very limited due to the more complex structure and spatial characteristics of fibrous materials. The aim of this research was to analyze the effects of selected EPD process parameters and the structural characteristics of fibrous carriers on the kinetics of the process and the microscopic characteristics of the deposited layers. The influence of solution characteristics, process parameters, and carrier structures obtained using two different techniques (melt blown and spun-bonded) were analyzed. The morphology and structure of the created deposits were analyzed using scanning electron microscopy and computed tomography, and molecular structure analysis was performed with Fourier Transform Infrared spectroscopy. The surface mass and thickness of fibrous poly (lactic acid)-based carriers were analyzed in accordance with the respective standards. This study serves as a basis for discussion and further development of this method with regard to fibrous materials for medical applications.

Effects of electrophoretic deposition process parameters on the mechanical properties of graphene carboxyl‐grafted carbon fiber reinforced polymer composite

ABSTRACTCarbon fiber (CF) modification by grafting of various graphene‐based nanofillers (GBN) by electrophoretic deposition (EPD) technique was proven to be a successful technique to enhance the out‐of‐plane performance of carbon fiber reinforced polymer (CFRP) composites. Graphene carboxyl (G‐COOH) grafting on carbon fiber by electrophoretic deposition (EPD) is a promising technique to improve the mechanical properties of CFRP composites. To our knowledge, there is a dearth of literature available on the effect of EPD process parameters on the mechanical behavior of modified CFRP composites. The aim of this study is to evaluate the effect of nanofiller concentration in the suspension, applied current, and the time of deposition during EPD on the mechanical behavior of nanophase CFRP composites, thus making it a novel work. With increasing concentration, interlaminar shear strength (ILSS) improved consistently and has shown a maximum enhancement of 24.7% than that of neat CFRP composite at 1.5 g/L nanofiller concentration, whereas flexural strength remained almost unaffected with varying concentration. On the contrary, variation of deposition current has affected the flexural strength but not ILSS. The maximum flexural strength was obtained at a deposition current of 5.0A with an improvement of 16.3% in comparison with neat CFRP samples. However, both flexural strength and ILSS of hybrid CFRP composites have shown improvement with increasing deposition time. At 60 min of deposition, ILSS and flexural strength have shown maximum improvements of 35.0 and 26.6%, respectively, when compared to control specimen. After evaluating the effect of process parameters future scope of the work involves the optimization of parameters for EPD of G‐COOH. Fractographic analysis of the fractured samples was performed using scanning electron microscope (SEM) to apprehend prominent failure mechanisms. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48925.

Preparation of YSZ electrolyte coating on conducting porous Ni–YSZ cermet by DC and pulsed constant voltage electrophoretic deposition process for SOFCs applications

In this article, electrolyte coating of solid oxide fuel cells (SOFCs) based on yttria stabilized zirconia (YSZ) on Ni-YSZ cermet fuel cells anode in ethanol was investigated using pulsed constant voltage and DC electrophoretic deposition (EPD). The NiO-YSZ substrate was prepared by hydraulic pressing of mixed YSZ, NiO and starch powders following pre-sintering at 1200 °C for 3 h. The NiO-YSZ composite was reduced in hydrogen atmosphere in order to produce Ni-YSZ cermet. The suspension properties and EPD process parameters were investigated. The YSZ electrolyte was sintered at 1350 °C for 4 h. The morphology of sintered YSZ electrolyte coating was investigated by scanning electron microscope (SEM) and optical microscopy (OM). Results showed that dense and uniform coatings were deposited in ethanol with solid concentration of 10 g/L of YSZ, 0.5 g/L of iodine at distance of anode to cathode being 5 mm. The thickness of YSZ electrolyte after 6 min of deposition with pulsed constant voltage and DC electrophoretic deposition were 20 and 88 ± 1 μm, respectively.

Electrophoretic deposition of trimanganese tetraoxide coatings on Ni-coated SUS 430 steel interconnect

A uniform trimanganese tetraoxide (Mn3O4) coating has been prepared on Ni-coated SUS 430 steel by novel electrophoretic deposition (EPD) approach based on stable Mn3O4 suspension which has been achieved in ethanol medium with iodine (I2) as dispersant. Different suspension characteristics and deposition kinetics have been systematically studied to optimize the suspension chemistry and deposition process parameters. The suitable EPD conditions including the current density (1 mA cm−2), deposition time (10 s) and I2 concentration (1.2 g L−1) are applied to deposit uniform nano-Mn3O4 coating. It is also revealed that the deposited mass and the thickness of Mn3O4 coatings can be controlled by adjusting the EPD process parameters. The Mn2O3/(Mn,Cr)3O4/Cr2O3 oxide is formed via oxidizing the coated SUS 430 stainless steel and no Cr-containing species migrates outwards.

A review of key parameters for effective electrophoretic deposition in the fabrication of solid oxide fuel cells

This paper reviews recent progress in electrophoretic deposition (EPD), particularly in solid oxide fuel cells (SOFCs). EPD is a simple, cost-effective, and geometrical flexible colloidal process. With its excellent control of thickness and other morphological characteristics, it is favored for the fabrication of SOFCs because each component layer of an SOFC has different requirements. However, the effectiveness of EPD is closely related to the suspension stability and EPD processing parameters. Maintaining a stable suspension and optimizing the EPD processing parameters are essential to achieve a dense and uniform deposition layer. Key parameters in maintaining the suspension stability are generally categorized into colloidal related parameters, including particle size and solid loading, and suspension media related parameters, including dielectric constant and conductivity. The effects of these parameters are often reflected by the zeta potential of the suspension, which can be manipulated by using charging agents to maintain a stable state. The deposition time and applied voltage are key parameters in optimizing the EPD process through their effects on the deposition rate. The effects of these parameters on particle surface charges and on the EPD mechanism are discussed.

Influence of process parameters on the electrophoretic deposition of zirconia nanoparticle coatings

Ceramic coatings have been widely used to enhance material surface properties, such as corrosion and wear resistance. Towards this goal, several coating fabrication techniques, including plasma spray, sol-gel, physical/chemical vapor deposition, as well as electrophoretic deposition (EPD) have been studied. EPD offers the advantage of a relatively simple and economic method that requires low deposition times. In this context, the purpose of the present work was to study the effect of EPD process parameters on the morphology of zirconia (ZrO2) nanoparticle coatings fabricated onto a graphite substrate. To achieve this, the stability of the colloidal precursor was first evaluated using zeta potential measurements of nanoparticle suspensions of different pH values. Moreover, EPD parameters such as applied voltage and nanoparticle concentration in the precursor solution were varied in order to gain insight into the chronoamperometric response of the prepared coatings. A clear effect of both, voltage and nanoparticle concentration in the precursor was observed. Furthermore, the influence of substrate preparation conditions on the morphology of the resulting coatings was also analyzed. Surface treatment prior to coating deposition appeared to impact the roughness of the final ZrO2 coating.

Optimizing in Vitro Impedance and Physico-Chemical Properties of Neural Electrodes by Electrophoretic Deposition of Pt Nanoparticles.

Neural electrodes suffer from an undesired incline in impedance when in permanent contact with human tissue. Nanostructures, induced by electrophoretic deposition (EPD) of ligand-free laser-generated nanoparticles (NPs) on the electrodes are known to stabilize impedance in vivo. Hence, Pt surfaces were systematically EPD-coated with Pt NPs and evaluated for impedance as well as surface coverage, contact angle, electrochemically active surface area (ECSA) and surface oxidation. The aim was to establish a systematic correlation between EPD process parameters and physical surface properties. The findings clearly reveal a linear decrease in impedance with increasing surface coverage, which goes along with a proportional reduction of the contact angle and an increase in ECSA and surface oxidation. EPD process parameters, prone to yield surface coatings with low impedance, are long deposition times (40-60 min), while high colloid concentrations (>250 μg mL-1 ) and electric field strengths (>25 V cm-1 ) should be avoided due to detrimental NP assemblage effects.

Electrophoretic Deposition of Two-Dimensional Titanium Carbide (MXene) Thick Films

Herein, we demonstrate the fabrication of Ti3C2Tx MXene films using electrophoretic deposition (EPD). A systematic study under constant voltage conditions from aqueous and propylene carbonate-based suspensions was performed to investigate the effects of the EPD process parameters on film morphology, flake orientation, and functional properties. From measured suspension properties, the kinetics of deposition from both suspension media were successfully described by the well-established Sarkar model of EPD. Remarkably, EPD-processed films have electrical conductivities of 7400 S/cm, on par with the highest values reported in the literature for Ti3C2Tx MXene. When employed as electrochemical capacitor electrodes in 1 M H2SO4, the capacitances were comparable to literature values. Given the process scalability and the morphological control that is possible, these results bode well for EPD as a fast, high-throughput method for making MXene films.

Electrophoretic Deposition of Chitosan/Clobetasol Propionate Composite Micro-Pattern Scaffolds: Fabrication Process and Material Properties

Introduction: Electrophoretic deposition (EPD) is an efficient bottom-up technology that enables the fabrication of self-standing structures based on biopolymers. Thin or thick films, deposited on patterned working electrodes, replicate, under suitable processing parameters, the substrate morphology: by peeling them off the substrates, structures with controlled three-dimensional morphologies can be obtained. Moreover, the mild EPD conditions allow to process sensitive organic molecules, such as drugs, without impairing their structure and activity. In this work we used EPD-based replica technique in order to design Chitosan strips which are loaded with specific amount of Clobetasol propionate, in order to design with a one-pot approach drug delivery systems for topical oral administration. Materials and Methods: Titanium cathode substrates (Ti, grade 2) were patterned via mechanical micro-drilling of regular square lattices of rectangular holes (F = 500-1000 mm, distance = 100-500 mm). Processing conditions have been optimized in order to reproduce the patterns: square waves (75-100 V, duty cycle = 20 min.) have been used in 30% water + 70% ethanol bath (pH~5.0, [Chitosan] = 1gr L-1, [Clobetasol] = 12.5 mg L-1). Obtained films were mechanically removed after freeze-drying. Specimens were further crosslinked (1% w/w Genipin solution (5mg L-1 in ethanol)) in order to modulate their overall behavior. Obtained specimens were characterized in terms of mechanical, water uptake in different environments (PBS, acidic and alkaline solutions), morphology properties, and drug delivery. Results and discussion: Optimum conditions to modulate both thickness and morphology of chitosan strips were determined by investigating the effects of the initial pH, ethanol/water bath concentration, and EPD processing parameters. A uniform distribution of pores and a precise replica of the shape of the pattern has been obtained. In order to study the presence of Clobetasol propionate in Chitosan strips, the fabricated materials were re-dissolved in acidic water/ethanol solutions and evaluated by spectrophotometer(Figure 1): the effective incorporation of drug has been tuned by adjusting the starting EPD solutions Chitosan/Clobetasol propionate composite structure showed different behaviors as a consequence of both morphology and microstructure in both water uptake and tensile properties. The cross-linked scaffolds show lower strain at break with a higher Young’s modulus, compared to the noncross-linked ones. They also showed a less degree of swelling (165%-330%) relative to the non-cross-linked ones (240%-370%). Conclusion: EPD has been exploited as a powerful technique to precise replicate micro-patterned substrates and to effectively incorporate drugs in a one-pot approach. Properties of obtained structures can be further modulated in order to design a family of biopolymers based structures that can be advantageously used in different topical drug delivery applications. Figure 1

Fine-tunable micro-patterns in Chitosan-based scaffolds: fabrication process and material properties

Fine-tunable micro-patterns in Chitosan-based scaffolds: fabrication process and material properties

전기영동적층법을 통한 판상 알루미나 입자와 전기영동 수지의 배향 유무기 복합체 제조 및 물성평가

Plate-shaped inorganic particles are coated onto a stainless steel substrate by the electrophoretic deposition of a precursor slurry which includes the inorganic particles of Al₂O₃ and polymer resin in mixed solvents to mimic the abalone shell structure, which is a composite of plate-shaped inorganic particles and organic interlayer binding materials with a layered orientation. The process parameters of the electrophoretic deposition include the voltage, coating time, and conductivity of the substrate. In addition, the suspension parameters are the particle size, concentration, viscosity, conductivity, and stability. We prepared an organic-inorganic composite coating with a high inorganic solid content by arraying the plate-shaped Al₂O₃ particles and electrophoretic resin via an electrophoretic deposition method. We analyzed the effect of the slurry composition and the electrophoretic deposition process parameters on the physical, mechanical and thermal properties of the coating layer, i.e., the thickness, density, particle orientation, Young"s modulus and thermogravimetric analysis results.

Anodic Electrophoretic Deposition of TiO<sub>2</sub> Nanoparticles Synthesized Using Sol Gel Method

Many researches on electrophoretic deposition of TiO2 nanoparticles (NPs) use commercial TiO2 nanoparticles from Degussa. TiO2 from Degussa is not use in this research because in order to make the TiO2 nanoparticle electronically charged and move under an applied constant voltage, a small amount of iodine and acetylacetone needs to be added to the suspension. It is suggested that the H+ ions generated by the reaction is absorbed on the suspended particles making them positively charged. For anodic EPD, negatively charged nanoparticles are required. In this research TiO2 nanoparticles were prepared by adding 1 ml of titanium isopropoxide dilute with 1 ml ethanol to 10 ml DI water and stirrer under 0°C for 4 hr. As prepared TiO2 nanoparticle were centrifuged at 5500 rpm for 10 min to isolate the particles from the solution. Then the TiO2 nanoparticles were resuspended in ethanol or water. TiO2 nanoparticle with particle diameter of 4.66 nm and anatase phase were produced. Important electrophoretic deposition process parameters, such as apparent pH of the TiO2 NPs, applied voltage, deposition time and solid loading, were studied during electrophoretic deposition of TiO2 nanoparticles.

Multiwalled Carbon Nanotubes Reinforced Hydroxyapatite‐Chitosan Composite Coating on Ti Metal: Corrosion and Mechanical Properties

Multiwalled carbon nanotubes (MWCNT) reinforced Hydroxyapatite‐chitosan composite coating is developed on Titanium metal by single step Electrophoretic deposition (EPD). By suitably controlling EPD process parameters, it has been possible to co‐deposit MWCNT and hydroxyapatite (HAp) electrophoretically and chitosan electrochemically on Ti metal from acetic acid/water/ethanol mixed solvent containing dissolved chitosan. At optimized process parameters, the coating contains uniform incorporation of MWCNT in porous HAp‐chitosan matrix, having composition of 10–12 wt% chitosan, 10–15 wt% MWCNT, rest HAp, as determined by thermogravimetric analysis. Raman spectra of composite coating reveal almost unaffected characteristics of carbon nanotubes. Adhesion strength and microhardness of composite HAp‐chitosan‐MWCNT coating increases compared with HAp coating. Composite coating is found to be highly corrosion resistance with corrosion current at 9 nA/cm2. The apatite growth after immersion in simulated body fluid for 10 days shows that the composite HAp‐chitosan‐MWCNT coating is bioactive in nature.

Short Review: Electrophoretic Deposition (EPD) on Non-Conductive Substrate

The application of electrophoretic deposition (EPD) technique for deposition of thick and thin film deposition has been extended not only on to electrically conducting materials but also to non-conducting material. The review encompasses the fundamental aspects of EPD technique and specific factors influencing the EPD process on non-conducting substrate. Important EPD processing parameters, during EPD on non-conducting substrate discussed are types of substrate, counter-electrode substrate and substrate additive. The parameters were discussed based on the up-to-date comprehensive overview of the current research progress in the field of EPD on non-conducting material.

Selective Deposition of TiO<sub>2 </sub>during Monolayer Formation of TiO<sub>2</sub> and Iron Oxide Nanocrystals by Electrophoretic Deposition in Non-Polar Solvents

The electrophoretic deposition of TiO2 iron oxide nanocrystal monolayers from stable, mixed colloidal suspensions by electrophoretic deposition using non polar solvents is reported. The selective deposition of TiO2 was accomplished by controlling the mobility of the nanocrystals and the voltage during electrophoretic deposition. The effect of the electrophoretic deposition processing parameters (voltage and particle mobility) on the promotion and suppression of nanocrystal deposition was investigated.

Fabrication of supported Ca-doped lanthanum niobate electrolyte layer and NiO containing anode functional layer by electrophoretic deposition

The technique of electrophoretic deposition (EPD) has been applied for the preparation of a dense calcium-doped lanthanum niobate electrolyte film. La0.995Ca0.005NbO4 (LCN) powder was suspended in a solution of acetylacetone, iodine and water. The effects of suspension composition and deposition conditions were analyzed in order to identify a suitable set of EPD process parameters. The powders were deposited on a composite substrate of LCN, NiO, binder and graphite. A dense 8μm film of lanthanum niobate supported on a porous substrate was obtained after sintering at 1200°C. The technique was found to be effective also for the deposition of a mixture of NiO and LCN powders which, after sintering, would form LCN/NiO anode functional layer. Electrochemical characterization of the supported LCN film was performed by applying a LCN/NiO counter electrode.

Residual stress and mechanical properties of Al2O3/ZrO2 functionally graded material prepared by EPD from 2‐butanone based suspension

Electrophoretic deposition (EPD) is an attractive forming process to fabricate plate shaped binary functionally graded materials (FGMs) from suitable stable suspensions. In the present work, the capability to produce Al2O3 and ZrO2 functionally graded bulk material by means of EPD from a non‐aqueous stable suspension based on 2‐butanone, n‐butylamine and cellulose nitrate solution is presented. The EPD processing parameters and sintering are described, and the density of the FGM composite, hardness, toughness and residual stresses are measured using indentation methods on cross‐sections of the sample. Scanning electron microscopy confirmed that the sintered body is an FGM.