Papers by Keyword: AAO

Abstract: Porous Anodic Aluminum oxide (PAAO) is a porous oxide layer resulting from anodization. The structure of PAAO is influenced by anodization parameters, i.e., voltage and electrolyte composition. Increasing anodization voltage can affect the process of pore formation and oxide growth during anodization. Adding additives such as ethanol, propanol, and polyethylene glycol (PEG) can increase pore regularity and affect the structure of PAAO. In this study, tobacco extract (TE) was added to the oxalic acid-based anodizing solution. TE has many active compounds that may affect pore formation and oxide growth. Morphological analysis shows decreased pore diameter when adding tobacco extracts with concentrations of 0, 0.1, and 0.5 g/L, namely 43.92, 41.42, and 37.8 nm at anodization voltage 40 V. In anodization with a voltage of 60 V, a decrease in pore diameter was obtained with 46.47, 34.24, and 26.8 nm for adding tobacco extract 0, 0.1, and 0.5 g/L. The thickness of PAAO increases from 6.45 µm to 16.87 µm with increasing anodization voltage and tobacco extract concentration. The increase of tobacco extract concentration can lead to the decrease of the XRD peak intensity, where the sequence of the most significant decrease was observed for the peaks of (111), (220), (200), and (311), respectively. A decrease in the intensity ratio of (111) and (220) AAO peaks indicates the influence of tobacco extract on the anodization process. Further thermal analysis by Thermo-gravimetric (TG) shows an increase in mass loss from 1.47 to 5.37% with increasing tobacco extract concentration from 0 g/L to 0.5 g/L. TG results indicate the incorporation of tobacco extract in the inner pore wall.

Abstract: Large-scale stannous oxide (SnO) nanowires were synthesized via a template and catalyst-free thermal oxidation process. After annealing Sn nanowires embedded AAO template in atmosphere, we observed a large scale of SnO nanowires. SnO nanowires were first prepared via the electrochemical deposition and an oxidization method based on an AAO template. The preparation of SnO nanowires use aluminum sheet (purity 99.999%) and then two-step anodization procedure to obtain raw alumina mold. Finally, transparent alumina mold (AAO template) were obtained by the reaming, soaking with phosphoric acid for 20 minutes and a stripping process. We get a pore size of < 20 nm transparent alumina mold. In order to electroplating needs, we produce platinum film on the bottom surface of AAO template by using sputtering method as the electrode of electroplating deposition. The structure was characterized by X-ray diffraction (XRD). High resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) with x-ray energy dispersive spectrometer (EDS) was used to observe the morphology. The EDS spectrum showed that components of the materials are Sn and O. FE-SEM results show the synthesized SnO nanowires to have an approximate length of ~ 10 - 20 μm with a highly aspect ratio > 500. SnO nanowires with an Sn/O atomic ratio of ~ 1 : 1 were observed from EDS. The crystal structure of SnO nanowires showed that all the peaks within the spectra can be indexed to SnO with a tetragonal structure. This studies may lead to the use of the 1D structure nanowires into electronic nanodevices and/or sensors, thus leading to nanobased functional structures.

Abstract: This research presents how to use high current density (2.85A/dm²) to do 6061 aluminum alloy hard anodization. There are five steps during the process including mechanical polishing, anodization, acid spitting, sealing and surface cleaning. By using electrochemical molds which we designed and controlling the electrolyte temperature at-2°C, then we could obtain ordering anodization film with 20nm pore size and 33.3μm thickness. However, there are some situations should be overcome such as raising the success rate of sealing and reducing the defects on the AAO surface by means of adjusting the parameters such as the current density, final voltage, electrolyte temperature, etc.

Abstract: Polydimethylsiloxane-2-[2-tert-Butoxycarbonylamino-(1H-pyrazol-4-yl)-propionylamino] -3-phenyl-propanoic acid (PDMS-BCPA) is a newly developed stereo-specific membrane that interacts with S configuration of enantiomers as chiral recognition sites. In this study, realization of PDMS-BCPA nanomembrane was achieved via anodized aluminum oxide (AAO) template synthesis approach followed by the attachment of synthesized chiral selector (BCPA) using simple immersion method. The effect of surface modification and the attachment with chiral selector were investigated and characterized using Fourier Transform Infrared spectroscopy (FT-IR), Field Emission Scanning Electron Microscopic (FE-SEM) and Atomic Force Microscopic (AFM) methods. The characterization via these methods indicates the synthesized BCPA as chiral selector was successfully attached onto the PDMS surface. The enantioselectivity of PDMS-BCPA nanomembrane was verified by the separation of alpha cypermethrin enantiomer.

Abstract: A simple method to indium tin alloy and oxide nanowires were achieved by using the extrusion molding process in the air. Eutectic indium tin bulk were firstly injected into AAO templates. After dissolving AAO, the indium tin nanowires were collected in ethanol. Furthermore, in order to have oxide nanowires, alloy nanowires were directly oxidized by heat treatment in the air below its melting point for 24 hours. Finally, crystalline indium-tin oxide and indium oxide nanowires with diameters 90-110 nm and lengths 2-20 μm were obtained.

Abstract: In this study, sludge reduction by ultrasound combining anaerobic-anoxic-oxic system (AAO) was developed and examined. Compared with AAO process, 38.07, 46.07 and 50.98% of excess sludge reduction could be obtained by ultrasonic combining AAO system (sludge return ratios of 40%, 60%, and 80%). When the sludge return ratio is 60%, ultrasound combining AAO system can achieve the best sludge reduction effect. Chemical oxygen demand (COD) removal rates of ultrasound combining AAO system were 88.21, 89.77, and 90.31%, respectively. The introduction of sludge disruption by ultrasound pretreatment did not affect the COD removal ability of the AAO system, whereas increased in the COD removal efficiency. This combined biological treatment system could realize sludge reduction and improve nutrient removal efficiencies.

Abstract: We report a facile and efficient way to fabricate sensitive substrates for surface-enhanced Raman scattering (SERS) via sputtering Au nanoparticles on the surface of porous anodic aluminum oxide (AAO). This substrate could reduce the detection limit of Rhodamine 6G (R6G) to 10^-12 M. Moreover, it exhibits excellent reproducibility and the relative standard deviation value of SERS intensity at 616 cm^-1 is about 12%. More importantly, it can be scaled up for high-throughput production with low cost and large scale.

Abstract: Uniform Y₂O₃:Tb³⁺ nanowires with diameters of about 70 nm were fabricated using the anodic aluminum oxide template (AAO). The Y₂O₃:Tb³⁺ nanowires and Y₂O₃:Tb³⁺/AAO composite were characterized by using powder X-ray diffraction (XRD), scanning electron microscope (SEM) and spectrofluorometer techniques. The Y₂O₃:Tb³⁺ nanowires are amorphous phase in symmetry as the annealing temperature was lower than 1000 °C. And the cubic Y₂O₃: Tb³⁺ nanowires were formed partly as the annealing temperature approached to 1000 °C. The spectral measurements indicate that the excitation and emission intensity increased with the increasing annealing temperature as well as annealing time. The lifetime of ⁵D₄-⁷F₅ transition becomes longer with the increasing annealing temperature and time in Y₂O₃:Tb³⁺/AAO composite.

Abstract: This paper discussed the fabrication of anodic aluminum oxide (AAO)/CaO core-shell membrane by anodization and sol-gel processes and evaluated the relationship between the Al2O3/CaO and CO2 by thermodynamic calculation. According to thermodynamic property that CaO can reacts with CO2 forming calcium carbonate (CaCO3) in a lower temperature ranges, CaCO3 can also be decomposed to CaO in a higher temperature ranges. Because the reversible reaction property that CaO can be a CO2 absorbent/ de-absorbent. We address that AAO based on core-shell nanotubes structure to achieve such a demand. The captured CO2 can further convert to fuel material of hydrocarbons.

Abstract: Antidot arrays of various diameters were patterned in permalloy thin films to explore their magnetic behavior. Porous anodic alumina had been used as a template to fabricate magnetic films with antidot array. Permalloy had been fabricated by depositing Ni₈₀Fe₂₀ onto anodic alumina membrane templates. The film thickness was 30 and 40 nm and the diameters of antidot varied from 200 to 350 nm. The coercivity of the antidot arrays is greater than that of unpatterned films and shows weak dependence on antidot diameter. The increase of the pore diameter was suggested to enhance domain wall pinning. The coercivity reaches a maximum value for the antidot array with the smallest pore diameter and reduces to an almost constant value for the antidot arrays with larger pore diameters.