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An Z, Sun S, Dong B. An ab initio molecular dynamics investigation of the behaviour of amorphous substances in anodic aluminium oxide under electric field. Sci Rep 2024; 14:10454. [PMID: 38714715 PMCID: PMC11076534 DOI: 10.1038/s41598-024-58975-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/05/2024] [Indexed: 05/10/2024] Open
Abstract
In order to elucidate the diffusion behaviour of ions in alumina during the anodic alumina process, the effects of electric field strength, hydration content, and electrolyte on amorphous alumina and hydrated alumina were studied using ab initio molecular dynamics. The results show that the diffusion rate of ions in alumina increases with the increase in electric field strength, but there is an extreme value. The maximum diffusion rate of Al ions in alumina monohydrate is 21.8 μm2/ms/V, while in alumina trihydrate, it is 16.7 μm2/ms/V. The ionic diffusion rate of hydrated alumina is one to two orders of magnitude larger than that of anhydrous amorphous alumina due to the effect of the drag of H ions, which reduces the migration activation energy. Electrolytes also affect the diffusion rate of alumina through the action of H ions. The increase in H ions will not only enhance the diffusion rate of hydrated alumina but also render the hydrous compound more vulnerable to breakdown.
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Affiliation(s)
- Zeyu An
- School of Materials Science and Engineering, Hubei University, Wuhan, Hubei, 430000, People's Republic of China
| | - Shiyang Sun
- School of Mechanical Engineering, Inner Mongolia University of Science & Technology, Baotou, Inner Mongolia, 014010, People's Republic of China
| | - Binghai Dong
- School of Materials Science and Engineering, Hubei University, Wuhan, Hubei, 430000, People's Republic of China.
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Dutovs A, Popļausks R, Putāns O, Perkanuks V, Jurkevičiūtė A, Tamulevičius T, Malinovskis U, Olyshevets I, Erts D, Prikulis J. In situ optical sub-wavelength thickness control of porous anodic aluminum oxide. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:126-133. [PMID: 38317824 PMCID: PMC10840541 DOI: 10.3762/bjnano.15.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/11/2024] [Indexed: 02/07/2024]
Abstract
Porous anodic aluminum oxide (PAAO), sometimes referred to as nanoporous anodic alumina, serves as a cost-effective template for nanofabrication in many fields of science and engineering. However, production of ultrathin PAAO membranes with precise thickness in the optical sub-wavelength range remains challenging because of difficulties regarding process control at the initial stage of anodic oxidation. In this study, we demonstrate a technique for consistently manufacturing PAAO with the targeted thickness. An electrochemical cell with an optical window was designed for reflectance spectroscopy of PAAO during anodization. Real-time fitting of spectra to a transfer-matrix model enabled continuous monitoring of the thickness growth of the PAAO layer. Automation software was designed to terminate the anodization process at preset PAAO thickness values. While the concept was illustrated using the widely used method of anodization in a 0.3 M oxalic acid electrolyte with a 40 V potential, it can be readily customized for other protocols. PAAO layers with effective thickness below 300 nm could be produced with a few nanometers accuracy using single-crystal aluminum substrates. The results were confirmed using spectroscopic ellipsometry. The method for controlling the thickness during anodization eliminates the necessity of sample sectioning for electron microscopy and is particularly valuable for the small-scale production of PAAO-based functional optical coatings.
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Affiliation(s)
- Aleksandrs Dutovs
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Raimonds Popļausks
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Oskars Putāns
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Vladislavs Perkanuks
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Aušrinė Jurkevičiūtė
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
- Institute of Materials Science of Kaunas University of Technology, K. Baršausko St. 59, Kaunas LT-51423, Lithuania
| | - Tomas Tamulevičius
- Institute of Materials Science of Kaunas University of Technology, K. Baršausko St. 59, Kaunas LT-51423, Lithuania
- Department of Physics, Faculty of Mathematics and Natural Sciences, Kaunas University of Technology, Studentų St. 50, Kaunas LT-51368, Lithuania
| | - Uldis Malinovskis
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Iryna Olyshevets
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Donats Erts
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
- Faculty of Chemistry, University of Latvia, 1 Jelgavas Str., Riga LV-1004, Latvia
| | - Juris Prikulis
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
- Faculty of Physics, Mathematics and Optometry, University of Latvia, 3 Jelgavas Str., Riga LV-1004, Latvia
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Białek E, Włodarski M, Norek M. Designing porous photonic crystals for MIR spectral region-a deeper insight into the anodic alumina layer thickness versus charge density relation. NANOTECHNOLOGY 2023; 34:125603. [PMID: 36595263 DOI: 10.1088/1361-6528/aca546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
The mid-infrared region (MIR) is crucial for many applications in security and industry, in chemical and biomolecular sensing, since it contains strong characteristic vibrational transitions of many important molecules and gases (e.g. CO2, CH4, CO). Despite its great potential, the optical systems operating in this spectral domain are still under development. The situation is caused mainly by the lack of inexpensive and adequate optical materials which show no absorption in the MIR. In this work, we present an easy and affordable way to develop 1D photonic crystals (PCs) based on porous anodic alumina for MIR region. The porous PCs were produced by the pulse anodization of aluminum using charge-controlled mode. The first order photonic stopbands (λ1) were located within ca. 3.5-6.5μm. Annealing of the material at 1100 °C for an hour has allowed to recover the wavelength range from around 5.8 to 7.5μm owing to the decomposition of the absorption centers (oxalate anions) present in the anodic oxide framework while maintaining the PC structural stability. The spectral position and the shape of the resonances were regulated by the charge passing under high (UH) and low (UL) voltage pulses, porosity of the correspondingdHanddLsegments, and dura tion of the process (ttot). The thickness of thedHanddLlayers was proportional to the charge passing under respective pulses, with the proportionality coefficient increasing with the applied voltage. Despite the constant charge (2500 mC cm-2) applied during the anodization, the thickness of anodic alumina (d) increased with applied voltage (10-60 V) and anodizing temperature (5 °C-30 °C). This behavior was ascribed to the different kinetics of the anodic alumina formation prompted by the variable electrochemical conditions. The photonic material can be used in portable nondispersive gas sensors as an enhancement layer operating up to around 9μm.
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Affiliation(s)
- Ewelina Białek
- Institute of Materials Science and Engineering, Faculty of Advanced Technologies and Chemistry, Military University of Technology, Str. gen Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland
| | - Maksymilian Włodarski
- Institute of Optoelectronics, Military University of Technology, Str. gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland
| | - Małgorzata Norek
- Institute of Materials Science and Engineering, Faculty of Advanced Technologies and Chemistry, Military University of Technology, Str. gen Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland
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Li C, Ni Y, Gong J, Song Y, Gong T, Zhu X. A review: research progress on the formation mechanism of porous anodic oxides. NANOSCALE ADVANCES 2022; 4:322-333. [PMID: 36132683 PMCID: PMC9417932 DOI: 10.1039/d1na00624j] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/19/2021] [Indexed: 06/16/2023]
Abstract
Owing to the great development potential of porous anodic oxides (PAO) in many fields, research on their formation mechanisms, fabrication processes and applications has a history of more than ten years. Although compared with research on the fabrication processes and applications of PAO, research on their formation mechanisms started late, several mainstream theories have been formed in the academic community, including the field-assisted dissolution (FAD) theory, the field-assisted ejection (FAE) theory, the self-organization theory, the ionic and electronic current theory and the oxygen bubble mould effect. This review will focus on summarizing the core views of the mainstream mechanisms mentioned above and comparing the explanations for some of their classical experimental phenomena.
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Affiliation(s)
- Chengyuan Li
- Key Laboratory of Soft Chemistry and Functional Materials of Education Ministry, Nanjing University of Science and Technology Nanjing 210094 China
| | - Yilin Ni
- Key Laboratory of Soft Chemistry and Functional Materials of Education Ministry, Nanjing University of Science and Technology Nanjing 210094 China
| | - Jingjing Gong
- School of Design Art and Media, Nanjing University of Science and Technology Nanjing 210094 China
| | - Ye Song
- Key Laboratory of Soft Chemistry and Functional Materials of Education Ministry, Nanjing University of Science and Technology Nanjing 210094 China
| | - Tianle Gong
- Key Laboratory of Soft Chemistry and Functional Materials of Education Ministry, Nanjing University of Science and Technology Nanjing 210094 China
| | - Xufei Zhu
- Key Laboratory of Soft Chemistry and Functional Materials of Education Ministry, Nanjing University of Science and Technology Nanjing 210094 China
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Peculiarities of Aluminum Anodization in AHAs-Based Electrolytes: Case Study of the Anodization in Glycolic Acid Solution. MATERIALS 2021; 14:ma14185362. [PMID: 34576586 PMCID: PMC8468596 DOI: 10.3390/ma14185362] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/28/2022]
Abstract
The anodization of aluminum (Al) in three alpha-hydroxy acids (AHAs): glycolic (GC), malic (MC), and citric (CC), was analyzed. Highly ordered pores in GC were obtained for the first time. However, the hexagonal cells were characterized by a non-uniform size distribution. Although common features of current density behavior are visible, the anodization in AHAs demonstrates some peculiarities. The electric conductivity (σ) of 0.5 M GC, MC, and CC electrolytes was in the following order: σ(CC) > σ(MC) > σ(GC), in accordance with the acid strength pKa(CC) < pKa(MC) < pKa(GC). However, the anodization voltage, under which a self-organized pore formation in anodic alumina (AAO) was observed (Umax), decreased with increasing pKa: Umax(CC) > Umax(MC) ≥ Umax(GC). This unusual behavior is most probably linked with the facility of acid ions to complex Al and the active participation of the Al complexes in the AAO formation. Depending on the AHA, its tendency and different modes to coordinate Al ions, the contribution of stable Al complexes to the AAO growth is different. It can be concluded that the structure of Al complexes, their molecular mass, and the ability to lose electrons play more important roles in the AAO formation than pKa values of AHAs.
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Zhang J, Yu Y, Fang P, Liu L, Yue H, Ou J, Han A. Anodization of aluminum in a sealed container. Electrochem commun 2021. [DOI: 10.1016/j.elecom.2021.107086] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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Lu N, Zhang J, Dan Y, Sun M, Gong T, Li X, Zhu X. Growth of porous anodic TiO2 in silver nitrate solution without fluoride: Evidence against the field-assisted dissolution reactions of fluoride ions. Electrochem commun 2021. [DOI: 10.1016/j.elecom.2021.107022] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Chen S, Ni Y, Zhang J, Dan Y, Zhang W, Song Y, Zhu X. Double-anode anodization of metal Ti in two beakers. Electrochem commun 2021. [DOI: 10.1016/j.elecom.2021.106991] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Zhou Q, Niu D, Feng X, Wang A, Ying Z, Zhang J, Lu N, Zhu J, Zhu X. Debunking the effect of water content on anodizing current: Evidence against the traditional dissolution theory. Electrochem commun 2020. [DOI: 10.1016/j.elecom.2020.106815] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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TiO2 nanotube arrays with a volume expansion factor greater than 2.0: Evidence against the field-assisted ejection theory. Electrochem commun 2020. [DOI: 10.1016/j.elecom.2020.106717] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Zhou Q, Tian M, Ying Z, Dan Y, Tang F, Zhang J, Zhu J, Zhu X. Dense films formed during Ti anodization in NH4F electrolyte: Evidence against the field-assisted dissolution reactions of fluoride ions. Electrochem commun 2020. [DOI: 10.1016/j.elecom.2020.106663] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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