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Fan CC, Wang CC, Lu CJ. A stamped aluminium gas chromatographic column disk employing directly grown anodic aluminium oxide stationary phase for the separation of aromatic and chlorinated compounds. Analyst 2024; 149:482-489. [PMID: 38059506 DOI: 10.1039/d3an01301d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
In this study, mesoporous anodic aluminium oxide (AAO) with moderate polarity was used as a GC stationary phase to demonstrate the applicability to various compound species. The fluidic channel measured 6 meters in length and had a cross-section area of 0.127 mm2. The column disk measured 6.2 cm in diameter and was fabricated through a stamping process on an aluminium substrate. The AAO stationary phase was directly grown on the aluminium substrate through an anodization process using oxalic acid as the electrolyte. The pore size of the AAO stationary phase was approximately 50-70 nm, with film thicknesses ranging from 6-20 μm. AAO based on oxalic acid exhibited significantly reduced surface polarity, making it suitable for separating polarizable and slightly polar compounds. The theoretical plate number for benzene had reached 1800 plates per meter, and for n-butane, it had reached 2500 plates per meter. A complex mixture of 16 compounds spanning alkanes, olefins, aromatics, and chlorinated hydrocarbons was effectively separated in 8 minutes with the temperature programmed to 200 °C.
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Affiliation(s)
- Chih-Chieh Fan
- Department of Chemistry, National Taiwan Normal University, 88, Sec.4, Tingzhou Rd., 11677, Taipei, Taiwan.
| | - Chih-Chia Wang
- Department of Chemical and Materials Engineering, Chung-Cheng Institute of Technology, NDU, 75, Shiyuan Rd., Daxi Dist., Taoyuan City 335, Taiwan
| | - Chia-Jung Lu
- Department of Chemistry, National Taiwan Normal University, 88, Sec.4, Tingzhou Rd., 11677, Taipei, Taiwan.
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2
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Sadilov I, Eliseev A, Eliseev A, Chumakova A, Kurtina D, Vasiliev R, Petukhov D. The origin for hydrocarbons fast transport and photoswitching permeation behavior in grafted laminar CdTe membranes. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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3
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Fan CC, Liu YH, Lu CJ. Separation of C1–C15 Alkanes with a Disk-Shaped Aluminum Column Employing Mesoporous AAO as the Stationary Phase. Anal Chem 2022; 94:15570-15577. [DOI: 10.1021/acs.analchem.1c05479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chih-Chieh Fan
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Yi-Hsin Liu
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Chia-Jung Lu
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
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4
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Roslyakov IV, Kushnir SE, Tsymbarenko DM, Sapoletova NA, Trusov LA, Napolskii KS. New insight into anodization of aluminium with focused ion beam pre-patterning. NANOTECHNOLOGY 2022; 33:495301. [PMID: 36049458 DOI: 10.1088/1361-6528/ac8e75] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 08/31/2022] [Indexed: 06/15/2023]
Abstract
The self-ordered anodic aluminium oxide (AAO) structure consists of micron-scale domains-defect-free areas with a hexagonal arrangement of pores. A substantial increase in domain size is possible solely by pre-patterning the aluminium surface in the form of a defect-free hexagonal array of concaves, which guide the pore growth during subsequent anodization. Among the numerous pre-patterning techniques, direct etching by focused gallium ion beam (Ga FIB) allows the preparation of AAO with a custom-made geometry through precise control of the irradiation positions, beam energy, and ion dosage. The main drawback of the FIB approach includes gallium contamination of the aluminium surface. Here, we propose a multi-step anodizing procedure to prevent gallium incorporation into the aluminium substrate. The suggested approach successfully covers a wide range of AAO interpore distances from 100 to 500 nm. In particular, anodization of FIB pre-patterned aluminium in 0.1 M phosphoric acid at 195 V to prepare AAO with the interpore distance of about 500 nm was demonstrated for the first time. The quantification of the degree of pore ordering reveals the fraction of pores in hexagonal coordination above 96% and the in-plane mosaicity below 3° over an area of about 1000μm2. Large-scale defect-free AAO structures are promising for creating photonic crystals and hyperbolic metamaterials with distinct functional properties.
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Affiliation(s)
- I V Roslyakov
- Department of Materials Science, Lomonosov Moscow State University, 119991 Moscow, Russia
- Kurnakov Institute of General and Inorganic Chemistry RAS, 119991 Moscow, Russia
| | - S E Kushnir
- Department of Materials Science, Lomonosov Moscow State University, 119991 Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - D M Tsymbarenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - N A Sapoletova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - L A Trusov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
- Department of Materials Science, MSU-BIT University, Shenzhen 517182, People's Republic of China
| | - K S Napolskii
- Department of Materials Science, Lomonosov Moscow State University, 119991 Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
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5
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Podgolin SK, Petukhov DI, Loimer T, Eliseev AA. Mass flow and momentum flux in nanoporous membranes in the transitional flow region. Phys Chem Chem Phys 2021; 23:17134-17141. [PMID: 34369508 PMCID: PMC8489186 DOI: 10.1039/d1cp02797b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An experimental study of momentum transfer in nanoporous polymeric track-etched membranes with pore diameters ranging from 100 to 1300 nm and nanochannel lengths of 12-20 μm was performed using He, N2, CO2, and SF6 propellants in a wide range of plenum and background pressures. Mass flux through the membranes was elaborated as a combination of Knudsen diffusion and viscous flow at Knudsen numbers above 0.1 and become choked at lower Knudsen numbers. The discharge coefficient for the membranes attained was 0.6, making the permeation rate similar to that of thin orifices. The effect is attributed to the mirror reflection of the molecules from the pore walls at low angles of incidence. The exhaust gas velocity is found to be dependent on the plenum to background pressure ratio and channel length-to-diameter ratio, reaching 0.9 of the velocity of the gas expanded to vacuum (up to 2 M). Close to an isothermal expansion occurs in nanochannels of all sizes. A general quantitative description for gas expansion in nanochannels is provided. The highest thrust is generated in the choked flow regime with the SF6 propellant and a value of 4.5 N cm-2 is attained at a propellant consumption of 0.165 kg (cm2 s)-1 for the membranes with 1300 nm nanochannels. The specific impulse of 138 s is reached for helium. The results show the prospects of the utilization of nanoporous membranes in cold gas propulsion systems.
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Affiliation(s)
- Stepan K Podgolin
- Department of Materials Science, Lomonosov Moscow State University, 1-73 Leninskiye Gory, Moscow, 11 9991, Russia.
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Petukhov D, Kan A, Chumakov A, Konovalov O, Valeev R, Eliseev A. MXene-based gas separation membranes with sorption type selectivity. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2020.118994] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Anodic alumina membrane capacitive sensors for detection of vapors. Talanta 2020; 219:121248. [PMID: 32887139 DOI: 10.1016/j.talanta.2020.121248] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 11/23/2022]
Abstract
Here we report membrane capacitive sensors based on anodic aluminum oxide (AAO) Au/AAO/Au structures fabricated by aluminum anodization, followed by gold electrodes sputtering on the countersides of porous ceramic membrane. Electrochemical impedance spectroscopy with AC amplitude 5-100 mV in the frequency range of 1-1000 Hz was utilized for sensor characterization in the presence of water and organic vapors in a full range of P/P0. The sensors illustrate ultimate sensitivity to ambient environment with exponential-scale capacitance relation to vapors content resulting in typical 4-6 orders of magnitude response signal change for 15-85% P/P0 range at a single AC frequency, and up to 7 orders of magnitude response range for 0-100% P/P0 pressure range with using two different AC frequencies. In case of water vapors, the sensitivity increases from ~0.5 nF/RH% at ~20 RH% to over ~1.0 μF/RH% at ~80 RH%. The sensors are capable for highly accurate sensing of gas humidity as well as any dissociative vapors with pKa <30. They are also sensible to polar components with high enough dipole moment or polarizability. The capacitance is affected by any adsorbed molecules, including those having zero dipole moment. The data for sensor response to CH3OH, C2H5OH, CH2ClCHF2, i-C4H10 depending on partial pressures is provided. Due to high porosity (10-30%) and gaseous permeance (up to 200 m3(STP) m-2 bar-1 h-1) the sensors offer fast response rate and a possibility for flow-through measurements, providing also a mass-flow response option, which was tested with SF6, CO2, N2 and He. The basic principles of dielectric loss sensor and the equivalent scheme were proposed for sensor operation in different environment, allowing estimating sensor response.
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Sekiguchi K, Katsumata KI, Segawa H, Nakanishi T, Yasumori A. Fabrication of a Silica-Silica Nanoparticle Monolayer Array Nanocomposite Film on an Anodic Aluminum Oxide Substrate and Its Optical and Tribological Properties. ACS APPLIED MATERIALS & INTERFACES 2020; 12:27672-27681. [PMID: 32462860 DOI: 10.1021/acsami.0c03436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The fabrication and properties of silica nanoparticle monolayer arrays (SNMAs) immobilized on silica films on nanoporous anodic aluminum oxide (AAO) substrates by polymerization of silicic acid and a two-step spin-coating technique are reported. Reflection spectra of the obtained silica-SNMA nanocomposite films on AAO substrates were almost the same as those of the original AAO substrate. The coefficient of friction at an applied load of 0.98 N under dry conditions for a film fabricated under optimal conditions was significantly decreased by 76% with respect to that without a silica-SNMA nanocomposite film on an AAO substrate. The results also showed a lower coefficient of friction than that for MoS2 nanoparticles (commonly used for self-lubricating films) deposited on an AAO substrate. We demonstrate that the silica-SNMA nanocomposite film with an optimal nanoroughness, thickness, and wear resistance can be used as a novel coating film for AAO substrates with both a high color degree of freedom and a low coefficient of friction at a high applied load (ca. 1 N).
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Affiliation(s)
- Kazutoshi Sekiguchi
- Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
- Materials Research Laboratories, Nissan Chemical Corporation, 488-6 Suzumi-cho, Funabashi, Chiba 274-0052, Japan
| | - Ken-Ichi Katsumata
- Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
- Photocatalysis International Research Center, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Hiroyo Segawa
- Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Takayuki Nakanishi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Atsuo Yasumori
- Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
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9
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Leontiev A, Roslyakov I, Napolskii K. Complex influence of temperature on oxalic acid anodizing of aluminium. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.06.111] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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10
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Sadilov I, Petukhov D, Eliseev A. Enhancing gas separation efficiency by surface functionalization of nanoporous membranes. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.03.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Leontiev AP, Volkova OY, Kolmychek IA, Venets AV, Pomozov AR, Stolyarov VS, Murzina TV, Napolskii KS. Tuning the Optical Properties of Hyperbolic Metamaterials by Controlling the Volume Fraction of Metallic Nanorods. NANOMATERIALS 2019; 9:nano9050739. [PMID: 31091697 PMCID: PMC6566159 DOI: 10.3390/nano9050739] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/07/2019] [Accepted: 05/10/2019] [Indexed: 11/19/2022]
Abstract
Porous films of anodic aluminum oxide are widely used as templates for the electrochemical preparation of functional nanocomposites containing ordered arrays of anisotropic nanostructures. In these structures, the volume fraction of the inclusion phase, which strongly determines the functional properties of the nanocomposite, is equal to the porosity of the initial template. For the range of systems, the most pronounced effects and the best functional properties are expected when the volume fraction of metal is less than 10%, whereas the porosity of anodic aluminum oxide typically exceeds this value. In the present work, the possibility of the application of anodic aluminum oxide for obtaining hyperbolic metamaterials in the form of nanocomposites with the metal volume fraction smaller than the template porosity is demonstrated for the first time. A decrease in the fraction of the pores accessible for electrodeposition is achieved by controlled blocking of the portion of pores during anodization when the template is formed. The effectiveness of the proposed approach has been shown in the example of obtaining nanocomposites containing Au nanorods arrays. The possibility for the control over the position of the resonance absorption band corresponding to the excitation of collective longitudinal oscillations of the electron gas in the nanorods in a wide range of wavelengths by controlled decreasing of the metal volume fraction, is shown.
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Affiliation(s)
- Alexey P Leontiev
- Department of Materials Science, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Olga Yu Volkova
- Department of Materials Science, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Irina A Kolmychek
- Department of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Anastasia V Venets
- Department of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Alexander R Pomozov
- Department of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Vasily S Stolyarov
- Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia.
- Institute of Solid State Physics RAS, 142432 Chernogolovka, Russia.
- All-Russian Research Institute of Automatics n.a. N.L. Dukhov (VNIIA), 127055, 119991 Moscow, Russia.
| | - Tatiana V Murzina
- Department of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Kirill S Napolskii
- Department of Materials Science, Lomonosov Moscow State University, 119991 Moscow, Russia.
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
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12
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13
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Roslyakov IV, Gordeeva EO, Napolskii KS. Role of Electrode Reaction Kinetics in Self-Ordering of Porous Anodic Alumina. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.04.140] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Petukhov DI, Buldakov DA, Tishkin AA, Lukashin AV, Eliseev AA. Liquid permeation and chemical stability of anodic alumina membranes. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:561-570. [PMID: 28382245 PMCID: PMC5355881 DOI: 10.3762/bjnano.8.60] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 02/10/2017] [Indexed: 05/29/2023]
Abstract
A study on the chemical stability of anodic alumina membranes and their performance in long-term water and organic solvent permeation experiments is reported. Anodic alumina possesses high stability for both protonic and aprotonic organic solvents. However, serious degradation of the membrane occurs in pure water, leading to a drastic decrease of permeance (over 20% of the initial value after the passing of 0.250 m3/m2 of pure water). The drying of the membrane induces further permeance drop-off. The rate of membrane degradation strongly depends on the pH of the penetrant solution and increases in basic media. According to 27Al NMR and thermogravimetry results, the degradation of the membranes is associated with the dissolution of water-soluble [Al13O4(OH)24(H2O)12]7+ polyhydroxocomplexes and their further redeposition in the form of [Al(OH)4]-, resulting in channels blocking. This process intensifies in basic pH due to the high positive charge of the anodic alumina surface. An approach for improving anodic aluminum oxide stability towards dissolution in water by carbon CVD coating of the membrane walls is suggested.
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Affiliation(s)
- Dmitrii I Petukhov
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991 Leninskie hills 1–3, Russia
- Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia
| | - Dmitrii A Buldakov
- Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia
| | - Alexey A Tishkin
- Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia
| | - Alexey V Lukashin
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991 Leninskie hills 1–3, Russia
- Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia
| | - Andrei A Eliseev
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991 Leninskie hills 1–3, Russia
- Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia
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15
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16
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Chernova E, Petukhov D, Boytsova O, Alentiev A, Budd P, Yampolskii Y, Eliseev A. Enhanced gas separation factors of microporous polymer constrained in the channels of anodic alumina membranes. Sci Rep 2016; 6:31183. [PMID: 27498607 PMCID: PMC4976320 DOI: 10.1038/srep31183] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/13/2016] [Indexed: 11/18/2022] Open
Abstract
New composite membranes based on porous anodic alumina films and polymer of intrinsic microporosity (PIM-1) have been prepared using a spin-coating technique. According to scanning electron microscopy, partial penetration of polymer into the pores of alumina supports takes place giving rise to selective polymeric layers with fiber-like microstructure. Geometric confinement of rigid PIM-1 in the channels of anodic alumina causes reduction of small-scale mobility in polymeric chains. As a result, transport of permanent gases, such as CH4, becomes significantly hindered across composite membranes. Contrary, the transport of condensable gases (CO2, С4H10), did not significantly suffer from the confinement due to high solubility in the polymer matrix. This strategy enables enhancement of selectivity towards CO2 and C4H10 without significant loss of the membrane performance and seems to be prospective for drain and sweetening of natural gas.
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Affiliation(s)
- Ekaterina Chernova
- Department of Materials Science, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Dmitrii Petukhov
- Department of Materials Science, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Olga Boytsova
- Department of Materials Science, Lomonosov Moscow State University, Moscow, 119991, Russia
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Alexander Alentiev
- A. V. Topchiev Institute of Petrochemical Synthesis (TIPS) Russian Academy of Sciences, Moscow, 119991, Russia
| | - Peter Budd
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | - Yuri Yampolskii
- A. V. Topchiev Institute of Petrochemical Synthesis (TIPS) Russian Academy of Sciences, Moscow, 119991, Russia
| | - Andrei Eliseev
- Department of Materials Science, Lomonosov Moscow State University, Moscow, 119991, Russia
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17
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Petukhov DI, Eliseev AA. Gas permeation through nanoporous membranes in the transitional flow region. NANOTECHNOLOGY 2016; 27:085707. [PMID: 26821609 DOI: 10.1088/0957-4484/27/8/085707] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An experimental study on the permeability of anodic alumina (20-120 nm) and track-etched (30 nm) nanoporous membranes for different gases in the transitional flow regime is reported in the range of Knudsen numbers from 0.1 to 10. A significant variation (up to 30%) of the membrane permeance for different gases at the same Knudsen numbers is reported with certainty. It is established that this discrepancy relates to a molecule's effective collision area, which is poorly described in the frameworks of conventional gas permeation models. Two models are proposed for the description of the effect: self-diffusion of penetrate gases due to intermolecular collisions and enhancement of the slip flow contribution due to tangential momentum accommodation growth with the decrease of a molecule's effective collision area. The best fit parameters for the simultaneous fit of the experimental data with different models for 30 membrane-gas pairs are given.
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Affiliation(s)
- D I Petukhov
- Department of Chemistry, Moscow State University, Leninskie Hills 1-3, Moscow 119991, Russia. Physical-Technical Institute UB RAS, 132 Kirov Street, Izhevsk 426000, Russia
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Mattia D, Leese H. Controlled hydrothermal pore reduction in anodic alumina membranes. NANOSCALE 2014; 6:13952-13957. [PMID: 25315125 DOI: 10.1039/c4nr04661g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Porous anodic aluminium oxide nanostructures are popular templates for the fabrication of a wide range of nanomaterials. When open at both ends, they are now being used as model membranes, called anodic alumina membranes (AAM). In both cases, their appeal resides in the possibility of accurately controlling pore size via the anodization voltage, with a narrow size distribution. This characteristic, though, is maintained only in specific pore size ranges, reflecting specific ordering regimes in the material. Outside these domains, less ordered structures are obtained. Furthermore, the smallest pores currently achieved by anodization are about ∼10 nm in diameter, using sulphuric acid, which yields very thin and fragile nanostructured membranes. In this work we address these limitations by decoupling the control of pore size from the anodization stage. We achieve this by subjecting AAMs produced under a high order regime (40 V, 0.3 M oxalic acid) to a post-anodization hydrothermal treatment using steam. With this process we were able to decrease the pore size by 80% down to ∼10 nm. The membranes retain their integrity and are more robust than AAMs with the same pore structure produced via anodization in sulphuric acid.
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Affiliation(s)
- D Mattia
- Department of Chemical Engineering, University of Bath, BA27AY, UK.
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Roslyakov IV, Eliseev AA, Yakovenko EV, Zabelin AV, Napolskii KS. Longitudinal pore alignment in anodic alumina films grown on polycrystalline metal substrates. J Appl Crystallogr 2013. [DOI: 10.1107/s002188981302579x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A quantitative analysis of longitudinal pore alignment in anodic alumina films grown on polycrystalline metal substrates was performed on the basis of small-angle X-ray diffraction mapping. The very high sensitivity of the diffraction pattern to the orientation of the anodic alumina film allowed the average pore alignment within the irradiated area to be determined, with an accuracy better than 0.1°. It is shown that pores deviate from the orientation orthogonal to the metal surface by a small angle that is constant within a single-crystal grain. Strong correlation between the longitudinal pore alignment within the anodic alumina film and the grain structure of the aluminium substrate indicates the important role of the crystallographic orientation of the metal in the pore growth process.
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