<i>In Situ</i> Determination of the Pore Opening Point during Wet-Chemical Etching of the Barrier Layer of Porous Anodic Aluminum Oxide: Nonuniform Impurity Distribution in Anodic Oxide

Han, Haewook; Park, Sang-Joon; Jang, Jong Shik; Ryu, Hyun; Kim, Kyung Joong; Baik, Sunggi; Lee, Woo

doi:10.1021/am400520d

Cited by 102 publications

(108 citation statements)

References 32 publications

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“…One of the most-important features of porous AAO membranes is that the pore diameter (D p ) can be controlled precisely by chemical etching time (t etch ) and temperature [28]. As shown in Fig.…”

Section: Outer Layermentioning

confidence: 99%

Mechanisms of Nanoporous Alumina Formation and Self-organized Growth

Ling

2015

Nanoporous Alumina

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The synthesis of nanoporous alumina based on anodization process is a field of active research. In this chapter, some fundamental scientific topics toward formation mechanisms of nanoporous alumina will be discussed in detail.(1) The intrinsic mechanisms of mild and hard anodization processes: the definition of mild anodization (MA) and hard anodization (HA); the critical condition between MA and HA processes. (2) The origins of self-ordering phenomenon: the structure models of nanoporous alumina; the influence of electrical field and internal stress. (3) The growth models of nanoporous alumina: the classical growth models of nanoporous alumina; the advantages and disadvantages of present models; the physical and chemical processes during aluminum anodization. (4) The intrinsic relationship between anodization conditions and anodization processes: the influence of anodization voltage and current density; the influence of electrolyte system; the influence of other anodization conditions. (5) Controllable fabrication of nanoporous alumina: the relationship between anodization conditions and structural parameters (e.g., interpore distance, pore size); fabrication of regular nanoporous alumina (i.e., with highly ordered pores); fabrication of nanoporous alumina with complex pore structure. In addition to nanoporous alumina, the findings and conclusions in this chapter may also be applied in other valve metal anodization processes (e.g., Ti, Zr, W anodization).

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Section: Outer Layermentioning

confidence: 99%

Mechanisms of Nanoporous Alumina Formation and Self-organized Growth

Ling

2015

Nanoporous Alumina

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“…The incorporation of acid anions occurs via inward migrations under an electric field (E) during the anodization. The amount of incorporated acid anions and their spatial distribution in AAO depend on the type and concentration of electrolytes, anodizing potential (U), current density (j), and temperature (T) [28,[107][108][109][110][111][112]. The incorporated electrolyte anions influence the chemical, optical, and mechanical properties of porous AAOs.…”

Section: Pore Wideningmentioning

confidence: 99%

“…For a given set of pore widening conditions (i.e., temperature and concentration of an etchant solution), the rate of oxide etching is dependent on the chemical composition of the pore wall oxide [112]. Figure 4.8 shows the systematic increase in pore diameter (D p ) with the pore widening time (t etch ) for porous AAOs formed in H 2 SO 4 , H 2 C 2 O 4 , and H 3 PO 4 .…”

Section: Pore Wideningmentioning

confidence: 99%

Structural Engineering of Porous Anodic Aluminum Oxide (AAO) and Applications

Lee

2015

Nanoporous Alumina

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Porous anodic aluminum oxide (AAO) films can be conveniently produced by anodization of aluminum. Porous oxide layer formed on aluminum contains a large number of mutually parallel pores. Each cylindrical nanopore and its surrounding oxide constitute a hexagonal cell aligned normal to the metal surface. Under proper conditions, the oxide cells are self-organized to form a hexagonally close-packed structure. The novel and tunable structural features of porous AAOs have been intensively exploited for templated synthesis of a variety of functional nanostructures and also for fabrication of nanodevices. On the other hand, porous AAOs with modulated pores may provide an additional degree of freedom in templated synthesis. In addition, they can be used as model systems for systematically investigating structure-property relations of nanostructured materials. Based on the anodization techniques developed recently, one can fabricate porous AAOs with tailor-made internal pore structures. This chapter is devoted to conveying the most recent advances in structural engineering of porous AAOs and nanotechnology applications. In order to provide context, a brief description is given of the general structure and fundamental electrochemical processes associated with pore formation. Subsequently, two common anodizing techniques (i.e., mild and hard anodizations) that have been explored for nanotechnology applications are discussed. Next, various nanostructuring approaches for custom-designed porous AAOs are reviewed. The chapter covers the properties of porous AAOs derived from structural engineering and their applications to various nanotechnology researches and finally presents the challenges and future prospects.

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“…Because it is difficult to obtain such similar high-aspect ratio porous materials by other techniques, anodic porous alumina has been widely investigated by researchers in nano-science and engineering applications, such as fundamentals [5][6][7] [41]. In particular, anodizing in sulfuric, selenic, oxalic, malonic, tartaric, and phosphoric acid solutions under the appropriate electrochemical conditions causes self-ordering growth of the porous alumina [1,2,42].…”

Section: Introductionmentioning

confidence: 99%

“…Because it is difficult to obtain such similar high-aspect ratio porous materials by other techniques, anodic porous alumina has been widely investigated by researchers in nano-science and engineering applications, such as fundamentals [5][6][7], nanotemplates [8][9][10][11], optical devices [12][13][14], sensors [15][16][17], and catalysts [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Polymer nanoimprinting using an anodized aluminum mold for structural coloration

Kikuchi

Nishinaga

Natsui

2015

Applied Surface Science

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2 HighlightsHighly ordered aluminum dimple arrays are fabricated via etidronic acid anodizing.The ordered dimple arrays display structural coloration with a rainbow distribution.Aluminum nanostructures can be transferred to polymers via nanoimprinting.The nanostructured polymer surfaces also exhibit structural coloration. 3 AbstractPolymer nanoimprinting of submicrometer-scale dimple arrays with structural coloration was demonstrated. Highly ordered aluminum dimple arrays measuring 530 to 670 nm in diameter were formed on an aluminum substrate via etidronic acid anodizing at 210 to 270 V and subsequent anodic oxide dissolution. The nanostructured aluminum surface led to bright structural coloration with a rainbow spectrum, and the reflected wavelength strongly depends on the angle of the specimen and the period of the dimple array. The reflection peak shifts gradually with the dimple diameter toward longer wavelength, reaching 800 nm in wavelength at 670 nm in diameter. The shape of the aluminum dimple arrays were successfully transferred to a mercapto-ester ultra-violet curable polymer via self-assembled monolayer coating and polymer replications using a nanoimprinting technique. The nanostructured polymer surfaces with positively and negatively shaped dimple arrays also exhibited structural coloration based on the periodic nanostructure, and reflected light mostly in the visible region, 400-800 nm. This nanostructuring with structural coloration can be easily realized by simple techniques such as anodizing, SAM coating, and nanoimprinting.Keywords: Anodizing; Anodic Porous Alumina; Etidronic Acid; Structural Coloration; Nanoimprinting 4 IntroductionAnodic porous alumina possesses characteristic nanofeatures, including highly ordered porous structures with high-aspect ratio nanopores measuring several tens or hundreds of nm in diameter, and can easily be fabricated via aluminum anodizing in several appropriate acidic electrolyte solutions [1][2][3][4]. Because it is difficult to obtain such similar high-aspect ratio porous materials by other techniques, anodic porous alumina has been widely investigated by researchers in nano-science and engineering applications, such as fundamentals [5][6][7] [41]. In particular, anodizing in sulfuric, selenic, oxalic, malonic, tartaric, and phosphoric acid solutions under the appropriate electrochemical conditions causes self-ordering growth of the porous alumina [1,2,42]. Accordingly, highly ordered anodic porous alumina with a high aspect ratio has been successfully obtained on aluminum substrates. However, the cell diameter (interpore distance) of the porous alumina formed in these electrolyte solutions is limited to up to approximately 500 nm in diameter at the corresponding anodizing voltage of 200 V [1]. Therefore, a novel high-voltage electrolyte is required for the self-ordering of porous alumina with large-scale cell diameters.Recently, we reported a new self-ordering electrolyte for anodic porous alumina fabrication, etidronic acid (1-hydroxyethane-1,1-diphosphonic ...

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In Situ Determination of the Pore Opening Point during Wet-Chemical Etching of the Barrier Layer of Porous Anodic Aluminum Oxide: Nonuniform Impurity Distribution in Anodic Oxide

Cited by 102 publications

References 32 publications

Mechanisms of Nanoporous Alumina Formation and Self-organized Growth

Mechanisms of Nanoporous Alumina Formation and Self-organized Growth

Structural Engineering of Porous Anodic Aluminum Oxide (AAO) and Applications

Polymer nanoimprinting using an anodized aluminum mold for structural coloration

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