Facile preparation of porous alumina through-hole masks for sputtering by two-layer anodization

Yanagishita, Takashi; Masuda, Hideki

doi:10.1063/1.4961126

Cited by 7 publications

(5 citation statements)

References 22 publications

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“…It is known that AAO produced in a highly concentrated sulfuric acid electrolyte has a low chemical stability [35] and undergoes structural alterations when heated in water-based solutions [36]. So we decided to test the stability of our samples.…”

Section: Resultsmentioning

confidence: 99%

Anodic Alumina Photonic Crystals as Refractive Index Sensors for Controlling the Composition of Liquid Mixtures

et al. 2019

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Photonic crystals based on anodic aluminum oxide films are examined as refractive index sensors for controlling the composition of water-alcohol liquid mixtures. The position of the reflectance maximum corresponding to the first photonic stop band is used as the analytical signal. Impregnation of a photonic crystal with water-ethanol and water-glycerol mixtures results in a redshift of the reflectance maximum. A fairly high refractive index sensitivity, sufficient to determine the composition of water-ethanol and water-glycerol mixtures with an accuracy of about 1 wt.%, is observed. The detailed dependencies of the analytical signal on the composition of mixtures are experimentally investigated and compared with numerical calculations. Prospects and limitations of the refractive index sensors based on anodic alumina photonic crystals are discussed.

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Section: Resultsmentioning

confidence: 99%

Anodic Alumina Photonic Crystals as Refractive Index Sensors for Controlling the Composition of Liquid Mixtures

et al. 2019

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“…1 . A through-hole porous alumina mask with an ordered array of openings was prepared by two-step anodization followed by two-layer anodization [ 17 ]. The first anodization was carried out on electrochemically polished aluminum (99.99% purity) at a constant voltage of 40 V in 0.3 mol dm −3 oxalic acid at 30 °C for 3 h. The anodization voltage of 40 V is well-established as a self-ordering condition that produces a highly ordered pore arrangement in anodic alumina [ 18 ].…”

Section: Methodsmentioning

confidence: 99%

Au-Capped GaAs Nanopillar Arrays Fabricated by Metal-Assisted Chemical Etching

2017

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GaAs nanopillar arrays were successfully fabricated by metal-assisted chemical etching using Au nanodot arrays. The nanodot arrays were formed on substrates by vacuum deposition through a porous alumina mask with an ordered array of openings. By using an etchant with a high acid concentration and low oxidant concentration at a relatively low temperature, the area surrounding the Au/GaAs interface could be etched selectively. Under the optimum conditions, Au-capped GaAs nanopillar arrays were formed with an ordered periodicity of 100 nm and pillar heights of 50 nm.

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“…In the third technique, the AAO/Al was anodised for a third time in 12 M H 2 SO 4 at a constant voltage similar to the formation voltage, i.e., either 40 V or 25 V, at 0 • C for 20 min (for every 90 min of the second anodisation step). The detachment of the membrane was carried out in the mixed solution of CrO 3 and H 3 PO 4 at 30 • C for 15 min (for every 90 min of the second anodisation step) [27][28][29].…”

Section: The Wet Etching Of Two-layered Anodic Porous Aluminamentioning

confidence: 99%

Fabrication and Optimisation of Alumina Nanoporous Membranes for Drug Delivery Applications: A Comparative Study

Osama,

Handal,

El-Sayed

et al. 2024

Nanomaterials

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Neurodegenerative disorders cause most physical and mental disabilities, and therefore require effective treatment. The blood–brain barrier (BBB) prevents drug molecules from crossing from the blood to the brain, making brain drug delivery difficult. Implantable devices could provide sustained and regulated medication to solve this problem. Two electrolytes (0.3 M oxalic acid and 0.3 M sulphuric acid) were used to anodise Al2O3 nanoporous membranes, followed by a third anodisation in concentrated H2SO4 to separate the through-hole membranes from the aluminium substrate. FTIR, AFM, and SEM/EDX were used to characterise the membranes’ structure and morphology. The effects of the anodisation time and electrolyte type on the AAO layer pore density, diameter, interpore distance, and thickness were examined. As a model drug for neurodegenerative disorders, donepezil hydrochloride (DHC) was loaded onto thin alumina nanoporous membranes. The DHC release profiles were characterised at two concentrations using a UV–Vis spectrophotometer. Oxalic acid membranes demonstrated an average pore diameter of 39.6–32.5 nm, which was two times larger than sulphuric acid membranes (22.6–19.7 nm). After increasing the anodisation time from 3 to 5 h, all of the membranes showed a reduction in pore diameter that was stable regardless of the electrolyte type or period. Drug release from oxalic acid-fabricated membranes was controlled and sustained for over 2 weeks. Thus, nanoporous membranes as implantable drug delivery systems could improve neurodegenerative disease treatment.

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Facile preparation of porous alumina through-hole masks for sputtering by two-layer anodization

Cited by 7 publications

References 22 publications

Anodic Alumina Photonic Crystals as Refractive Index Sensors for Controlling the Composition of Liquid Mixtures

Anodic Alumina Photonic Crystals as Refractive Index Sensors for Controlling the Composition of Liquid Mixtures

Au-Capped GaAs Nanopillar Arrays Fabricated by Metal-Assisted Chemical Etching

Fabrication and Optimisation of Alumina Nanoporous Membranes for Drug Delivery Applications: A Comparative Study

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