Papers by Author: Saifollah Abdullah

Abstract: Polyvinylidene fluoride (PVDF) membranes were prepared with different compositions of SiO2 nanoparticles. PVDF is one of the most widely used in membrane technology. The molecular structure of PVDF fluoropolymer provides high chemical resistance, good mechanical properties and thermal stability. It also can be used as composites with inorganic nanoparticles such as SiO₂ to improve the performance and properties of the membrane. In this study, Dimethylacetamide (DMAc) was used as solvent. The prepared membranes were characterized using contact angle measurements with water, atomic force microscope (AFM) and scanning electron microscope (SEM) for the structures of the membranes and mechanical strength. The experimental results showed that additional of nanoSiO₂ will exhibit different characteristic on the microstructure and mechanical strength of the membrane.

Abstract: In this work, seeded porous silicon (PSi) was used as a substrate in the growth of ZnO nanostructures. PSi was prepared by electrochemical etching method. ZnO thin films as seeded were deposited via sol-gel spin coating method. ZnO nanostructures were grown on seeded PSi using hydrothermal immersion method. In order to study the effect of post-heat treatment on the substrate, post annealing temperature were varied in the range of 300 to 700 °C. The FESEM results shows ZnO thin film composed of nanoparticles were distributed over the PSi surface. Based on AFM characterization, the smoothest surface was produced at post annealing temperature of 500 °C. There are two different peaks appeared in PL characterization. The peak in near-UV range is belonging to ZnO thin films while a broad peak in visible range can be attributed to ZnO defects and PSi surface. In addition, FESEM, XRD and PL were used to characterize the ZnO nanostructures. The FESEM results revealed ZnO nano-flower were successfully grown on seeded PSi. Hexagonal wurtzite of ZnO with dominated by the plane (100), (002), and (101) was found by XRD characterization. Two different peaks in UV range and visible range can be attributed to ZnO nano-flower and various defects of ZnO, respectively.

Abstract: Zinc coated mild steel is usually applied to protect the substrate surface from corrosion. In this study, Zinc Oxide nanostructure layer will be used to protect the surface of mild steel from corrosion. The Zinc Oxide nanostructure will be synthesized by sol-gel method. After the solution was prepared, it then coated on mild steel surface using spin coater and anneal at different temperature to see the growth of Zinc Oxide nanostructures. After the sample has been coated it will characterize using FESEM, XRD and LPR.

Abstract: Titanium Dioxide, TiO₂ is one of the potential semiconductor materials. TiO₂ has much application such as for pigments, oxygen sensors, and photocatalyst. Recently, the researcher study on the other application and revealed that this material has a great potential to be use in nanocoating area. The objective of this paper is to produce TiO₂ nanostructured prepared by sol-gel method. Sol-gel was carried out using tetra (IV) isopropoxide (TTIP), absolute ethanol, Acetic Acid Glacial (GAA), Triton-X-100 and deionized water and all the solution was mixing by continuous stirring and heating. After finished prepare the sol-gel, solution will be spin coated onto glass substrate and annealed with different temperature for 2 hours. The particles were analyzed using Raman Spectroscopy to observe the crystallographic phase, and the morphology was evaluated through Atomic Force Microscopy (AFM). As a result, TiO₂ that annealed at 450°C shows the better nanostructured compared to other annealing temperature. Keywords: Titanium Dioxide (TiO₂); Sol-gel method ; Spin-coating ; Annealing process ; Raman spectroscopy

Abstract: Cotton coated titanium dioxide, TiO₂ was prepared by using immersion method. Three samples with different concentration which are 0.2 M, 0.5 M and 0.6 M of TiO₂ solution with fixed value of temperature and time immersion has been used in this project. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and Ultraviolet/Visible (UV-Vis) Spectrophotometer have been used to determine the properties of samples. The surface morphology of the cotton, crystalline phase of TiO₂ particles deposited on the cotton fiber and the amount of the TiO₂ particles dispersed in the water has been investigated. The existence of TiO₂ on the cotton fiber was identified by using SEM and XRD where the immersion method that has been used in this project contributed to the agglomerated TiO₂ particles on the surface of cotton fiber. None of the samples showed the formation of anatase crystalline phase of TiO₂ particle and UV-Vis showed the released of TiO₂ in the water was higher in the first immersion and decreased exponentially for the second, third and fourth immersion.

Abstract: This paper will present on preparation and characterizations of hybrid nanoTiO₂/ZnO using sol-gel spin coating techniques. The study involved of modification band-gap energy of Titanium Dioxide (TiO₂) at different precursor molecular concentration of Zinc oxide (ZnO). The FESEM (Field emission scanning electron microscope) morphological characterize shows TiO₂ and ZnO particle produced at nanoscale size. The compositional of both particles confirmed using EDAX (Energy Disperse Analyzer X-ray) analysis. The XRD (X-Ray diffraction) characterize measured the structural properties of anatase and rutile for TiO₂ as well as zincite for ZnO. By increasing ZnO molecular concentration, the crystallite size, d were decreased until the optimum sample, ratio of 4 TiO₂ : 1 ZnO, with value of 23.71 nm. For UV-VIS (Ultra-Violet/Visible Spectroscopy) measurement, we found the optical band-gap increased with increasing ZnO molecular concentration. The optical band-gap for optimum sample was 3.38 e.V represented this study has successfully improved the optical band-gap of TiO₂.

Abstract: Thins films of lanthanum phosphate (LaPO₄) were fabricated on glass substrate using successive layer by layer (LbL) assembly method subsequent with furnace annealing. Lanthanum Phosphate (LaPO₄) thin films were prepared through sol gel and spin coating technique from lanthanum nitrate and ammonium phosphate in ammonia solution. The surface morphology of films was studied through Atomic Force Microscopy (AFM). The images of LaPO₄ films had a RMS roughness below 50 nm and showed some aggregates. With increasing layers of LaPO₄, thus the surface roughness become thickest starts with range 13.926 nm to 33.020 nm. Two peaks, 448 and 465 nm is located in a blue-violet spectrum area.

Abstract: Lanthanum Phosphate (LaPO₄) nanostructures thin films have been successfully synthesized by sol-gel spin coating technique from lanthanum nitrate and ammonium phosphate in ammonia solution. The procedure starting with formation of homogenous and transparent solution followed with annealing to form the LaPO₄ nanostructures thin films. The films were annealed at different temperature to study its effect to the surface morphology and optical properties of the films. The phosphate particles are having near-spherical to rod-like nanostructures with an average size about 15 nm. The morphology is retained even the annealing temperature is increased. Furthermore, photoluminescence (PL) characterization of LaPO₄ also was reported. The effect of annealing temperature was discussing detail. The intensity as well as optical brightness is highly dependent on anneal temperature. Fourier transform infra red spectra of films obtained are similar to the previous synthesis of phosphate. Thus, confirmed the formation of LaPO₄ on the glass substrate.

Abstract: ZnO nanorods were prepared by immersion method deposited onto Silicon (Si) and gold-seeded Si (Au/Si) substrate. The annealing temperatures were varied from 400, 500 and 600 °C. The effect of annealing temperature on the surface morphology and photoluminescence characteristics was investigated. The samples were characterized by Field Emission Scanning Electron Microscope (FESEM) to study their morphology and structural properties while the optical properties were characterized at room temperature using Photoluminescence Spectroscope. The shape of ZnO showed growth of nanorods with hexagonal shape. As the annealing temperature increased, the morphology study indicates that particle size of ZnO decreased while the crystallinity increases. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors.

Abstract: Nanoparticles are now essential material to be used in material engineering, medicine and cosmetic application due to their chemical, mechanical and optical properties. Several experiments were designed to investigate the relationship effect of bead size using different bead size (4 mm and 2 mm) at fix grinding conditions. Changes in particles size produce were studied using dynamic light scattering method at 25 °C. The z-Average and polydipersity index for each particles size at different grinding were recorded. Using smaller size of zirconia bead will produced smaller size of C. asiatica than using larger bead size. As a result the smallest size particle by mean is 242 nm where 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition at 517 nm shows the smaller particles has a higher percentage of inhibition.