**1. Introduction**

Nowadays, surface engineering is of great scientific and technological relevance focused on the development of new methods to achieve desired surface properties and provide better performance of materials.

The methods of surface modification are used to develop a wide range of functional properties including physical, chemical, biological, electrical, electronic, magnetic, adhesion, mechanical, wear-resistant, and corrosion-resistant properties on the required substrate surfaces.

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The industrial sectors that demand the development and application of the surface modification of materials are the automotive, aerospace, missile, energy, electronics, biomedical, textile, petroleum, petrochemical, chemical, steel, energy, cement, machine tool, and construction industries [1].

of the process, are adhered to a surface. For this purpose, it is advisable to analyze the physicochemical environment to which a suspended particle is subjected, either dispersed or in the colloidal phase. One of the best known models for studying the colloidal phase or the stability of suspended particles is the double electrical layer (DEL), which consists of recognizing the distribution of electric charges around a particle surrounded by solvent molecules and coun-

Innovation in the Electrophoretic Deposition of TiO2 Using Different Stabilizing Agents and Zeta…

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The zeta potential (ζ) is an electrochemical parameter that allows estimating the nature of the surface charge of the suspended particles, establishing whether the electrophoretic deposition process is anodic or cathodic and deposition kinetic. For example, if we compare a ζ = 100 mV with a ζ = 10 mV, the electrophoretic velocity is expected to be 10 times higher. This effect results in more homogeneous deposits and the thickness will depend on the deposit time.

In this paper, the use of different stabilizing agents such as surfactants and biopolyelectrolytes with different ionic nature and chain length was proposed to improve the stability of the

On the other hand, the zeta potential was used as a strategy to predict the performance of the EPD process. The profiles of ζ = f (pH) and ζ = f (dose stabilizing agent) were made as a strategic guide to establish the best conditions of the EPD, in order to achieve homogeneous deposits in an efficient way (short times, mass yield, sufficient adhesion, and resistant to cor-

Titanium sheets were used as a substrate for their high mechanical resistance and corrosion, sectioned in square pieces with dimensions 1 × 1 cm and 0.1 cm thick for the cathode and

 **and different stabilizing agents**

dispersion were determined with the profiles ζ = *f* (pH). The zeta potential

dispersion. The TiO2

dispersions

The surface charge density, isoelectric point, and stabilizing agents-dosing strategy for the

measurement was performed using the SZ-100 of Horiba Scientific equipment based on stud-

The profiles of ζ = *f* (stabilizing agent dose) were performed to determine the dose of the

were prepared with water and water/ethanol mixtures (90:10 and 50:50) using surfactants of different chemical nature such as CTAB, SDS, Betaine, and Triton X-100 and a cationic

 **dispersions**

stabilizing agent and improve the stability of the TiO2

coatings have potential uses in biomedical applications, water treatment,

ter ions that define its solid–liquid interface [2–4].

**2.1. Metallographic preparation of titanium substrates**

TiO2

dispersions.

rosion). These TiO2

**2. Experimental**

formulation of TiO2

and photocatalytic materials.

3 × 3 cm and 0.1 cm for the anode.

**2.2. Profiles of ζ =** *f* **(pH) of TiO2**

**2.3. Colloidal titration of TiO2**

ies by López-Maldonado et al. [23, 24].

There are different methods that allow the coating of a surface, to mention some, such as painting, carburizing, nitriding, sputtering, electrophoretic deposition, spray coatings, electrodeposition, ion implantation, ion plating, thermal oxidation, laser cladding, electroless deposition, chemical vapor deposition, solvent casting, dip coating, and sol-gel coating [2].

Within the variety of coating methods, the electrophoretic deposition (EPD) has several advantages, such as low deposition time, simple and cheap equipment, little restriction of the shape of substrates; deposition is achieved both inside of the cavities and on the outside cavity surfaces, control the film thickness and uniformity, applicability to any powdered solid that forms a stable, a wide range of particle sizes, from micro- to nanometric particles (colloidal suspensions) [3].

Almost all types of substrates, including metal oxides, ceramics, polymers, and composite materials, can be coated by EPD with similar or different materials.

Using EPD, the coating of different substrates has been made with a variety of materials, to mention a few, metals, polymers, ceramics, glasses, carbon nanotubes, nanoparticles, zeolite, hydroxyapatite, silica, alumina, proteins, bacteria, and cells [4–8].

Moreover, considering the functionality and application the films can be used in antioxidant coatings, bioactive coating, cell fuel, tissue engineering, composites, medical implants, scaffolds, microelectronic devices, wear-resistant, sensors, nanoscale assembly, luminescent materials, gas diffusion electrode, biomedical, multilayer composites, bactericide surfaces, piezoelectric motors, photocatalyst and photovoltaics, corrosion protective, and water purification [9–22].

EPD is based on the movement of charged particles suspended in a solution through application of an external electric field (electrophoresis mechanism). This electric field enables the consolidation of particles into films, cast onto any shaped substrate, or into thick and bulk components.

The electrophoretic deposition process is generally described in three stages: the first consists in the application of an electric field between an anode and a cathode, which are submerged in the suspension of the charged particles, which causes the migration of the charged particles toward the opposite charged electrode. Subsequently, the particles begin to accumulate on the surface of the electrode resulting in the formation of a thin and thick film. Finally, a thermal treatment step is carried out to improve the characteristics of electrodeposits [1, 2].

To employ electrophoretic deposition successfully, a basic understanding of the colloidal stability, the deposition kinetics, and the constrained drying and sintering issues of the deposit is necessary.

Although the EPD technique is simple, it is necessary to understand the coupled electrical and physicochemical phenomena of the particles that are initially suspended, and at the end of the process, are adhered to a surface. For this purpose, it is advisable to analyze the physicochemical environment to which a suspended particle is subjected, either dispersed or in the colloidal phase. One of the best known models for studying the colloidal phase or the stability of suspended particles is the double electrical layer (DEL), which consists of recognizing the distribution of electric charges around a particle surrounded by solvent molecules and counter ions that define its solid–liquid interface [2–4].

The zeta potential (ζ) is an electrochemical parameter that allows estimating the nature of the surface charge of the suspended particles, establishing whether the electrophoretic deposition process is anodic or cathodic and deposition kinetic. For example, if we compare a ζ = 100 mV with a ζ = 10 mV, the electrophoretic velocity is expected to be 10 times higher. This effect results in more homogeneous deposits and the thickness will depend on the deposit time.

In this paper, the use of different stabilizing agents such as surfactants and biopolyelectrolytes with different ionic nature and chain length was proposed to improve the stability of the TiO2 dispersions.

On the other hand, the zeta potential was used as a strategy to predict the performance of the EPD process. The profiles of ζ = f (pH) and ζ = f (dose stabilizing agent) were made as a strategic guide to establish the best conditions of the EPD, in order to achieve homogeneous deposits in an efficient way (short times, mass yield, sufficient adhesion, and resistant to corrosion). These TiO2 coatings have potential uses in biomedical applications, water treatment, and photocatalytic materials.
