K. Aiempanakit

Fabrication and Characterization of Antibacterial Ag-TiO2 Thin Films Prepared by DC Magnetron Co-Sputtering Technique

In this study, silver-doped titanium dioxide (Ag-TiO2) thin films were prepared co-sputtering technique in order to promote photo-induced antibacterial applications. The high-purity Ag (99.995%) and Ti (99.995%) were simultaneously co-sputtering on BK7 glass and silicon (100) wafers substrate. The structure, morphology, surface roughness and optical properties were characterized by grazing-incidence X-ray diffraction (GIXRD), field-emission scanning electron microscopy (FE-SEM) and UV-Vis spectrophotometer, respectively. The results showed that the as-deposited Ag-TiO2 thin films had high transparency in the visible range. The antibacterial activity was studied in the presence and in the absence of UV irradiation against Escherichia coli as a model for Gram-negative bacteria. The results indicated that, in comparison to conventional TiO2 films, the Ag-TiO2 thin films exhibited excellent antibacterial properties under the UV illumination.

Functionalization of Au Nanoparticles on ZnO Nanorods through Low-Temperature Synthesis

Hybrid nanomaterials exhibit multi-functionalities, which is synergy or enhanced physical and optical properties over their single components with promising potentials for various applications in dye-sensitized solar cell and photocatalytic materials. In this present research, the Au nanoparticles were prepared at HAuCl4 concentration of 0.5 mM on ZnO nanorod templates and silicon wafer substrate by hydrothermal reaction process. The prepared samples were investigated the crystal structure, chemical composition and morphologies by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field-emission scanning electron microscopy (FESEM), respectively. The XRD results shown that ZnO was preferred orientation along the c-axis (002). The FE-SEM images indicated to the difference of size-Au NPs decorated on ZnO nanorods and silicon wafer. The relationship between the surface area and the size of Au NPs of the prepared samples was investigated and possible growing mechanism of Au NPs on ZnO nanorods templates will be discussed.

CTAB as a soft template for modified clay as filler in active packaging.

The role of modified clay has been employed in many areas of engineering research. Structure of clay was mainly focused on alumino-silicate layer and its form was presented as pillar layer. It composed of many ion exchanges inside. In industry, in order to use clay with higher efficiency, modification on surface and porosity has been developed. CTAB, one of the most effective cationic surfactant, was employed to modify the surface and porosity of clay.

Effect of Oxygen Flow Rate and Post Annealing on Vanadium Oxide Thin Films Prepared by DC Pulse Magnetron Sputtering

In this work, we investigated V2O5 thin films prepared by a DC pulse reactive magnetron sputtering at ambient conditions. The effects of oxygen flow rates during the film deposition and post annealing in air atmosphere were explored. The V2O5 thin films were sputtered from vanadium target onto silicon wafer and glass slide substrates at room temperature. The as-deposited V2O5 thin films were annealed at 200°C under air atmosphere. The films were then examined for their crystallinity, physical microstructures, and optical transmission. The crystallinity and morphology of the films were investigated by grazing incident x-ray diffraction, atomic force microscopy, and field-emission scanning electron microscopy. The optical transmission was determined by UV-Vis Spectrophotometer. The results showed that the as-deposited films were amorphous, whereas the post annealed films indicated V2O5 phase in all samples. The increase in the oxygen flow rates during the deposition led to the decrease in the deposition rate, film thickness, and film surface roughness. In addition, the oxygen flow can increase the average transmission of the V2O5 thin films. The effects of the annealing treatment of the optical transmission spectra will be discussed.

Effects of Precursor Concentration on Hexagonal Structures of ZnO Nanorods Grown by Aqueous Solution Method

The ZnO nanorods were fabricated on top of the seeded gold layer by the aqueous solution method with the solution of zinc nitrate and hexamethylenetetramine (HTMA) at 90°C for 24 hours. The variety of the ZnO nanorods were prepared and investigated based on the precursor concentrations, in a range of 1 to 40 mM. The physical morphologies and crystal structures were characterized by field-emission scanning electron microscopy (FE-SEM) and X-ray diffractometry (XRD), respectively. The results showed that, with the small precursor concentrations, the lateral growth of the nanorods was highly significant when compared to their axial growth. The precursor concentration of 20 mM was best optimized for the preparation of the ZnO nanorod arrays with the hexagonal structures at the highest rod diameter and length. At the higher concentrations, although the nanorod size remained nearly constant, the length was however rapidly decreased. Further analyses also proved that, with the increased precursor concentrations, the number density of the ZnO nanorods was progressively increased along with the more complete hexagonal wurtzite structures.

Vertical Alignment TiO2 Nanotube Based on Ti Film Prepared via Anodization Technique

A highly ordered nanotube TiO2 was successfully prepared from sputtered Ti metal film using anodization process. Ethylene glycol and ammonium fluoride was introduced as the electrolyte solution. The applied of anodizing voltage was systematically controlled between 20 - 60 volts along fabrication process, respectively. The physical characteristic of the fabricated TiO2 nanotube including anodizing rate, tube diameter and tube width was investigated through the characterization system as field emission scanning electron microscope (FE-SEM). According to cross-section FE-SEM photograph, the anodizing rate and tube width significantly increases when the anodizing voltage was future increased due to higher the electric field. Moreover, the tube diameter directly depends with the anodizing voltage also. The anodizing voltage provides a significant role on the feature of TiO2 nanotube. Finally, the fabricated nanotube TiO2 is potentially promising for Photo-activated application and Nanostructure template.

Investigation of Electrochromic WO3 Nanorods Prepared by DС Reactive Magnetron Sputtering with GLAD Technique

Tungsten oxide (WO3) nanorods were prepared by a DC reactive magnetron sputtering with a glancing-angle deposition (GLAD) technique, which promoted high surface area, for electrochromic applications. During the deposition, a high-quality tungsten target was sputtered under oxygen ambience on to Si (100) and glass/ITO substrates. The variation of the deposition time, which affected the length, size and patterns of the nanorods, was investigated based on their electrochromic properties. For physical studies, the prepared nanorods were examined by X-ray diffraction and field-emission scanning electron microscopy, which demonstrated moderately ordered nanorods with amorphous phase. The results showed that the length and size of nanorod were increased, in nearly linear order, with increasing the deposition time. For optical characteristics of the prepared films, the UV-Vis spectrophotometry was use to determined their transmission spectra and optical contrasts from the colored and bleached state. The electrochromic properties were also determined from cyclic voltammetry. The results indicated that, because of the optimal relations between the nanostructural length and size, the WO3 nanorods prepared at 75 minutes (approximately 422 nm) yielded the highest optical contrast and electrochromic functions.

Preparation of Titanium Dioxide Films on Water Wheel for Domestic Wastewater Treatment

Titanium dioxide (TiO2) was prepared by Sol-Gel technique that was coated on the grade 304-stainless steel. Effect of dip coated speed, number of coated cycles and annealed temperature on films properties were investigated. The optimum condition for film preparation was at dip coated speed of 0.12 cm/s, number of coated cycles of 20 cycles and annealed temperature of 500 °C. TiO2 film was crystal structure in anatase phase that had the main plane (101). Surface morphology of the TiO2 films formed grain that look like knobby shape. nanograin sizes were slightly difference that showed in the range of 10-50 nm. Under optimum condition, TiO2 film was used as photocatalyst to treat domestic wastewater. TiO2 film was coated on the paddles of water wheel and 24 paddles were used to create water wheel. Films surface area were contact to wastewater and the light around 0.504 m2 under working volume and working area of 0.0135 m3 and 0.09 m2, respectively. Under irradiation of the near UV with average intensity of 0.89 mW/cm2 over 24 hrs., and rotational speed of 17 rev/min. that were controlled by microcontroller box set. To compare treatment efficiency, uncoated TiO2 - water wheel (UTWW) was run in the same condition of coated TiO2 - water wheel (CTWW). The result showed that the CTWW had higher treatment efficiency than the UTWW. Especially for COD, TS, TDS and PO43-, CTWW had greater treatment efficiency than the UTWW that percentage difference were greater than 90%.

Structural and Optical Properties of TiO2 Thin Films Prepared by Thermal Oxidation of Ti Thin Films

Titanium dioxide (TiO2) films were prepared by thermal oxidation from Ti films. The Ti films were deposited on glass and silicon (100) wafer substrate by dc magnetron sputtering and subsequent with thermal oxidation process. The crystal structure and morphology of TiO2 films were estimated by using X-ray diffractometry (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. The optical property of TiO2 films was determined by UV-Visible spectrophotometer. The influences of annealing temperature between 200 to 500°C in air for 1 hour on the structure and optical properties of TiO2 films were investigated. The increasing of annealing temperature was directly affected the phase transition from Ti to TiO2. The optical and structural properties of TiO2 films are the best exhibited with increasing the annealing temperature at 500 °C.

Structural, Optical and Anti-Bacterial Properties of TiO2 Thin Films Prepared by DC Reactive Magnetron Sputtering

Recent studies demonstrated that, titanium oxide (TiO2) thin films, which kill bacteria and viruses under mild UV illumination, offers numerous potential applications. In this work, the TiO2 thin films were successfully deposited by DC reactive magnetron sputtering technique. The high-purity Ti target was sputtered on BK7 glasses and silicon (100) wafer substrates. The annealing treatment at various temperatures was next performed on the obtained samples. Their crystalline structure, film morphology and optical properties, as well as anti-bacterial activities, were investigated. The structure and morphology of films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM). The optical property was determined by UV-Vis spectrophotometer. After the post-annealing in air at higher than 200 °C, all the films showed crystallized mixture of anatase and rutile phase. The antibacterial properties of the TiO2 thin films were discussed.