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Nguyen MD, Simon J, Scott JW, Zimmerman AM, Tsai YCC, Halperin WP. Orbital-flop transition of superfluid 3He in anisotropic silica aerogel. Nat Commun 2024; 15:201. [PMID: 38172106 PMCID: PMC10764773 DOI: 10.1038/s41467-023-44557-5] [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: 04/19/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
Superfluid 3He is a paradigm for odd-parity Cooper pairing, ranging from neutron stars to uranium-based superconducting compounds. Recently it has been shown that 3He, imbibed in anisotropic silica aerogel with either positive or negative strain, preferentially selects either the chiral A-phase or the time-reversal-symmetric B-phase. This control over basic order parameter symmetry provides a useful model for understanding imperfect unconventional superconductors. For both phases, the orbital quantization axis is fixed by the direction of strain. Unexpectedly, at a specific temperature Tx, the orbital axis flops by 90∘, but in reverse order for A and B-phases. Aided by diffusion limited cluster aggregation simulations of anisotropic aerogel and small angle X-ray measurements, we are able to classify these aerogels as either "planar" and "nematic" concluding that the orbital-flop is caused by competition between short and long range structures in these aerogels.
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Affiliation(s)
- M D Nguyen
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA.
| | - Joshua Simon
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - J W Scott
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - A M Zimmerman
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - Y C Cincia Tsai
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - W P Halperin
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA.
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2
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Rawson SD, Bayram V, McDonald SA, Yang P, Courtois L, Guo Y, Xu J, Burnett TL, Barg S, Withers PJ. Tailoring the Microstructure of Lamellar Ti 3C 2T x MXene Aerogel by Compressive Straining. ACS NANO 2022; 16:1896-1908. [PMID: 35130692 PMCID: PMC8867911 DOI: 10.1021/acsnano.1c04538] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Aerogels are attracting increasing interest due to their functional properties, such as lightweight and high porosity, which make them promising materials for energy storage and advanced composites. Compressive deformation allows the nano- and microstructure of lamellar freeze-cast aerogels to be tailored toward the aforementioned applications, where a 3D nanostructure of closely spaced, aligned sheets is desired. Quantitatively characterizing their microstructural evolution during compression is needed to allow optimization of manufacturing, understand in-service structural changes, and determine how aerogel structure relates to functional properties. Herein we have developed methods to quantitatively analyze lamellar aerogel domains, sheet spacing, and sheet orientation in 3D and to track their evolution as a function of increasing compression through synchrotron phase contrast X-ray microcomputed tomography (μCT). The as-cast domains are predominantly aligned with the freezing direction with random orientation in the orthogonal plane. Generally the sheets rotate toward flat and their spacing narrows progressively with increasing compression with negligible lateral strain (zero Poisson's ratio). This is with the exception of sheets close to parallel with the loading direction (Z), which maintain their orientation and sheet spacing until ∼60% compression, beyond which they exhibit buckling. These data suggest that a single-domain, fully aligned as-cast aerogel is not necessary to produce a post-compression aligned lamellar structure and indicate how the spacing can be tailored as a function of compressive strain. The analysis methods presented herein are applicable to optimizing freeze-casting process and quantifying lamellar microdomain structures generally.
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Affiliation(s)
- Shelley D. Rawson
- Henry
Royce Institute, Department of Materials, The University of Manchester, Manchester M13 9PL, U.K.
| | - Vildan Bayram
- Department
of Materials, University of Manchester, Manchester M13 9PL, U.K.
| | | | - Pei Yang
- Department
of Materials, University of Manchester, Manchester M13 9PL, U.K.
| | | | - Yi Guo
- Department
of Materials, Imperial College London, London SW7 2BU, U.K.
| | - Jiaqi Xu
- Henry
Royce Institute, Department of Materials, The University of Manchester, Manchester M13 9PL, U.K.
| | - Timothy L. Burnett
- Henry
Royce Institute, Department of Materials, The University of Manchester, Manchester M13 9PL, U.K.
| | - Suelen Barg
- Department
of Materials, University of Manchester, Manchester M13 9PL, U.K.
- Institute
of Materials Resource Management, Augsburg
University, Augsburg 86159, Germany
| | - Philip J. Withers
- Henry
Royce Institute, Department of Materials, The University of Manchester, Manchester M13 9PL, U.K.
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3
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Synthesis, Characterizations and Catalysis of Sulfated Silica and Nickel Modified Silica Catalysts for Diethyl Ether (DEE) Production from Ethanol towards Renewable Energy Applications. Catalysts 2021. [DOI: 10.3390/catal11121511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sulfated silica (SO4/SiO2) and nickel impregnated sulfated silica (Ni-SO4/SiO2) catalysts have been successfully carried out for the conversion of ethanol into diethyl ether (DEE) as a biofuel. The aims of this research were to study the effects of acidity on the SO4/SiO2 and Ni-SO4/SiO2 catalysts in the conversion of ethanol into diethyl ether. This study focuses on the increases in activity and selectivity of SiO2 with the impregnation of sulfate and Ni metal, which had good activity and acidity and were less expensive. The SO4/SiO2 catalysts were prepared using TEOS (Tetraethyl Orthosilicate) as a precursor and sulfuric acid with various concentrations (1, 2, 3, 4 M). The results showed that SO4/SiO2 acid catalyst treated with 2 M H2SO4 and calcined at 400 °C (SS-2-400) was the catalyst with highest total acidity (2.87 g/mmol), while the impregnation of Ni metal showed the highest acidity value at 3%/Ni-SS-2 catalyst (4.89 g/mmol). The SS-2-400 and 3%/Ni-SS-2 catalysts were selected and applied in the ethanol dehydration process into diethyl ether at temperatures 175, 200, and 225 °C. The activity and selectivity of SS-2-400 and 3%/Ni-SS-2 catalysts shown the conversion of ethanol reached up to 9.54% with good selectivity towards diethyl ether liquid product formation.
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Shaheed N, Javanshir S, Esmkhani M, Dekamin MG, Naimi-Jamal MR. Synthesis of nanocellulose aerogels and Cu-BTC/nanocellulose aerogel composites for adsorption of organic dyes and heavy metal ions. Sci Rep 2021; 11:18553. [PMID: 34535724 PMCID: PMC8448726 DOI: 10.1038/s41598-021-97861-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 08/31/2021] [Indexed: 11/09/2022] Open
Abstract
MOFs compounds with open metal sites, particularly Cu-BTC, have great potential for adsorption and catalysis applications. However, the powdery morphology limits their applications. One of the almost new ways to overcome this problem is to trap them in a standing and flexible aerogel matrix to form a hierarchical porous composite. In this work, Cu-BTC/CNC (crystalline nanocellulose) and Cu-BTC/NFC (nanofibrillated cellulose) aerogel composites were synthesized using a direct mixing method by the addition of Cu-BTC powder to the liquid precursor solution followed by gelation and freeze-drying. Also, pure nanocellulose aerogels (CNC and NFC aerogels) have been synthesized from cellulose isolated from peanut shells. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra, and X-ray diffraction (XRD) were utilized to evaluate the structure and morphology of the prepared materials. The adsorption ability of pure CNC aerogel and Cu-BTC/NFC aerogel composite for organic dye (Congo Red) and heavy metal ion (Mn7+) was studied and determined by the UV-Vis spectrophotometry and inductively-coupled plasma optical emission spectrometry (ICP-OES), respectively. It was concluded that Cu-BTC/NFC aerogel composite shows excellent adsorption capacity for Congo Red. The adsorption process of this composite is better described by the pseudo-second-order kinetic model and Langmuir isotherm, with a maximum monolayer adsorption capacity of 39 mg/g for Congo Red. Nevertheless, CNC aerogel shows no adsorption for Congo Red. Both CNC aerogel and Cu-BTC/NFC aerogel composite act as a monolith standing solid reducer, which means they could remove permanganate ions from water by reducing it into manganese dioxide without releasing any secondary product in the solution.
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Affiliation(s)
- Nuhaa Shaheed
- Pharmaceutical and Heterocyclic Compounds Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran, Iran
| | - Shahrzad Javanshir
- Pharmaceutical and Heterocyclic Compounds Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran, Iran.
| | - Maryam Esmkhani
- Pharmaceutical and Heterocyclic Compounds Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran, Iran
| | - Mohammad G Dekamin
- Pharmaceutical and Heterocyclic Compounds Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran, Iran
| | - Mohammad Reza Naimi-Jamal
- Research Laboratory of Green Organic Synthesis and Polymers, Department of Chemistry, Iran University of Science and Technology, 16846, Tehran, Iran
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5
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Chong S, Riley BJ, Kuang W, Olszta MJ. Iodine Capture with Mechanically Robust Heat-Treated Ag-Al-Si-O Xerogel Sorbents. ACS OMEGA 2021; 6:11628-11638. [PMID: 34056318 PMCID: PMC8153970 DOI: 10.1021/acsomega.1c00852] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
Various radionuclides are released as gases during reprocessing of used nuclear fuel or during nuclear accidents including iodine-129 (129I) and iodine-131 (131I). These isotopes are of particular concern to the environment and human health as they are environmentally mobile and can cause thyroid cancer. In this work, silver-loaded heat-treated aluminosilicate xerogels (Ag-HTX) were evaluated as sorbents for iodine [I2(g)] capture. After synthesis of the base NaAlSiO4 xerogel, a heat-treatment step was performed to help increase the mechanical integrity of the NaAlSiO4 gels (Na-HTX) prior to Ag-exchanging to create Ag-HTX xerogels. Samples were characterized by powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller analysis, gravimetric iodine loading, nanoindentation, and dynamic mechanical analysis. The structural and chemical analyses of Ag-HTX showed uniform distribution of Ag throughout the gel network after Ag-exchange. After I2(g) capture, the AgI crystallites were observed in the sorbent, verifying chemisorption as the primary iodine capture mechanism. Iodine loading of this xerogel was 0.43 g g-1 at 150 °C over 1 day and 0.52 g g-1 at 22 °C over 33 days. The specific surface area of Ag-HTX was 202 m2 g-1 and decreased to 87 m2 g-1 after iodine loading. The hardness of the Na-HTX was >145 times higher than that of the heat-treated aerogel of the same starting composition. The heat-treatment process increased Young's modulus (compressive) value to 40.8 MPa from 7.0 MPa of as-made xerogel, demonstrating the need for this added step in the sample preparation process. These results show that Ag-HTX is a promising sorbent for I2(g) capture with good iodine loading capacity and mechanical stability.
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Affiliation(s)
- Saehwa Chong
- Pacific Northwest National
Laboratory, Richland, Washington 99354, United States
| | - Brian J. Riley
- Pacific Northwest National
Laboratory, Richland, Washington 99354, United States
| | - Wenbin Kuang
- Pacific Northwest National
Laboratory, Richland, Washington 99354, United States
| | - Matthew J. Olszta
- Pacific Northwest National
Laboratory, Richland, Washington 99354, United States
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6
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Gan G, Li X, Fan S, Wang L, Qin M, Yin Z, Chen G. Carbon Aerogels for Environmental Clean-Up. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201801512] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Guoqiang Gan
- State Key Laboratory of Fine Chemicals; Key Laboratory of Industrial Ecology and Environmental Engineering (MOE); School of Environmental Science and Technology; Dalian University of Technology; 116024 Dalian China
| | - Xinyong Li
- State Key Laboratory of Fine Chemicals; Key Laboratory of Industrial Ecology and Environmental Engineering (MOE); School of Environmental Science and Technology; Dalian University of Technology; 116024 Dalian China
- Department of Chemical and Biological Engineering; The Hong Kong University of Science and Technology; China
| | - Shiying Fan
- State Key Laboratory of Fine Chemicals; Key Laboratory of Industrial Ecology and Environmental Engineering (MOE); School of Environmental Science and Technology; Dalian University of Technology; 116024 Dalian China
| | - Liang Wang
- State Key Laboratory of Fine Chemicals; Key Laboratory of Industrial Ecology and Environmental Engineering (MOE); School of Environmental Science and Technology; Dalian University of Technology; 116024 Dalian China
| | - Meichun Qin
- State Key Laboratory of Fine Chemicals; Key Laboratory of Industrial Ecology and Environmental Engineering (MOE); School of Environmental Science and Technology; Dalian University of Technology; 116024 Dalian China
| | - Zhifan Yin
- State Key Laboratory of Fine Chemicals; Key Laboratory of Industrial Ecology and Environmental Engineering (MOE); School of Environmental Science and Technology; Dalian University of Technology; 116024 Dalian China
| | - Guohua Chen
- Department of Chemical and Biological Engineering; The Hong Kong University of Science and Technology; China
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7
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Lu Y, Li X, Yin X, Utomo HD, Tao NF, Huang H. Silica Aerogel as Super Thermal and Acoustic Insulation Materials. ACTA ACUST UNITED AC 2018. [DOI: 10.4236/jep.2018.94020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Liquid metal technology of synthesis of AlOOH anisotropic nanostructured aerogel. NUCLEAR ENERGY AND TECHNOLOGY 2017. [DOI: 10.1016/j.nucet.2017.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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9
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Jiang F, Hsieh YL. Cellulose Nanofibril Aerogels: Synergistic Improvement of Hydrophobicity, Strength, and Thermal Stability via Cross-Linking with Diisocyanate. ACS APPLIED MATERIALS & INTERFACES 2017; 9:2825-2834. [PMID: 28079358 DOI: 10.1021/acsami.6b13577] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A facile gelation cross-linking approach was devised to fabricate meso- and macroporous cellulose nanofibril (CNF) aerogels with multiple improved properties. CNF hydrogels made using a freezing-thawing method with a 94 kPa modulus were solvent exchanged with acetone and then cross-linked with methylene diphenyl diisocyanate (MDI) to produce aerogels with significantly improved compressive properties that follow a power law increment against aerogel density with impressive 1.69, 2.49, and 1.43 scaling factors for Young's modulus, yield stress, and ultimate stress, respectively. The optimally cross-linked aerogels had nearly tripled specific surface area (228 m2/g) and doubled pore volume (1 m3/g) from numerous new 9-12 nm wide mesopores as well as significantly improved thermal stability (43% char residue at 500 C vs 9.1% for un-cross-linked aerogel). Cross-linking also made the amphiphilic CNF aerogel highly hydrophobic and capable of completely separating chloroform from water via simple filtration. These nanocellulose aerogels show great promise for efficient and continuous separation of oils and hydrophobic liquids from water.
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Affiliation(s)
- Feng Jiang
- Fiber and Polymer Science, University of California , Davis, California 95616, United States
| | - You-Lo Hsieh
- Fiber and Polymer Science, University of California , Davis, California 95616, United States
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10
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Zuo L, Zhang Y, Zhang L, Miao YE, Fan W, Liu T. Polymer/Carbon-Based Hybrid Aerogels: Preparation, Properties and Applications. MATERIALS (BASEL, SWITZERLAND) 2015; 8:6806-6848. [PMID: 28793602 PMCID: PMC5455374 DOI: 10.3390/ma8105343] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 09/20/2015] [Accepted: 09/28/2015] [Indexed: 11/17/2022]
Abstract
Aerogels are synthetic porous materials derived from sol-gel materials in which the liquid component has been replaced with gas to leave intact solid nanostructures without pore collapse. Recently, aerogels based on natural or synthetic polymers, called polymer or organic aerogels, have been widely explored due to their porous structures and unique properties, such as high specific surface area, low density, low thermal conductivity and dielectric constant. This paper gives a comprehensive review about the most recent progresses in preparation, structures and properties of polymer and their derived carbon-based aerogels, as well as their potential applications in various fields including energy storage, adsorption, thermal insulation and flame retardancy. To facilitate further research and development, the technical challenges are discussed, and several future research directions are also suggested in this review.
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Affiliation(s)
- Lizeng Zuo
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, 220 Handan Road, Shanghai 200433, China.
| | - Youfang Zhang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, 220 Handan Road, Shanghai 200433, China.
| | - Longsheng Zhang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, 220 Handan Road, Shanghai 200433, China.
| | - Yue-E Miao
- State Key Laboratory of Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620, China.
| | - Wei Fan
- State Key Laboratory of Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620, China.
| | - Tianxi Liu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, 220 Handan Road, Shanghai 200433, China.
- State Key Laboratory of Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620, China.
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11
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Effect of polymer molecular weight and deposition temperature on the properties of silica aerogel/hydroxy-terminated poly(dimethylsiloxane) nanocomposites prepared by reactive supercritical deposition. J Supercrit Fluids 2015. [DOI: 10.1016/j.supflu.2014.12.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Wang W, Zhang Z, Zu G, Shen J, Zou L, Lian Y, Liu B, Zhang F. Trimethylethoxysilane-modified super heat-resistant alumina aerogels for high-temperature thermal insulation and adsorption applications. RSC Adv 2014. [DOI: 10.1039/c4ra08832h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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13
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Rechberger F, Heiligtag FJ, Süess MJ, Niederberger M. Assembly of BaTiO3Nanocrystals into Macroscopic Aerogel Monoliths with High Surface Area. Angew Chem Int Ed Engl 2014; 53:6823-6. [DOI: 10.1002/anie.201402164] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/24/2014] [Indexed: 01/01/2023]
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14
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Rechberger F, Heiligtag FJ, Süess MJ, Niederberger M. Anordnung von BaTiO3-Nanokristallen zu makroskopischen Aerogelmonolithen mit großer Oberfläche. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201402164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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Sanli D, Erkey C. Monolithic composites of silica aerogels by reactive supercritical deposition of hydroxy-terminated poly(dimethylsiloxane). ACS APPLIED MATERIALS & INTERFACES 2013; 5:11708-11717. [PMID: 24168319 DOI: 10.1021/am403200d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Monolithic composites of silica aerogels with hydroxyl-terminated poly(dimethylsiloxane) (PDMS(OH)) were developed with a novel reactive supercritical deposition technique. The method involves dissolution of PDMS(OH) in supercritical CO2 (scCO2) and then exposure of the aerogel samples to this single phase mixture of PDMS(OH)-CO2. The demixing pressures of the PDMS(OH)-CO2 binary mixtures determined in this study indicated that PDMS(OH) forms miscible mixtures with CO2 at a wide composition range at easily accessible pressures. Upon supercritical deposition, the polymer molecules were discovered to react with the hydroxyl groups on the silica aerogel surface and form a conformal coating on the surface. The chemical attachment of the polymer molecules on the aerogel surface were verified by prolonged extraction with pure scCO2, simultaneous deposition with superhydrophobic and hydrophilic silica aerogel samples and ATR-FTIR analysis. All of the deposited silica aerogel samples were obtained as monoliths and retained their transparency up to around 30 wt % of mass uptake. PDMS(OH) molecules were found to penetrate all the way to the center of the monoliths and were distributed homogenously throughout the cylindrical aerogel samples. Polymer loadings as high as 75.4 wt % of the aerogel mass could be attained. It was shown that the polymer uptake increases with increasing exposure time, as well as the initial polymer concentration in the vessel.
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Affiliation(s)
- D Sanli
- Department of Chemical and Biological Engineering, Koç University , 34450 Sariyer, Istanbul, Turkey
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16
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Müller R, Zhang S, Neumann B, Bäumer M, Vasenkov S. Study of Carbon Dioxide Transport in a Samaria Aerogel Catalyst by High Field Diffusion NMR. CHEM-ING-TECH 2013. [DOI: 10.1002/cite.201300041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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In situ atom transfer radical polymerization of styrene in the presence of nanoporous silica aerogel: Kinetic study and investigation of thermal properties. JOURNAL OF POLYMER RESEARCH 2013. [DOI: 10.1007/s10965-013-0163-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Heath L, Zhu L, Thielemans W. Chitin nanowhisker aerogels. CHEMSUSCHEM 2013; 6:537-44. [PMID: 23335426 PMCID: PMC3615177 DOI: 10.1002/cssc.201200717] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/23/2012] [Indexed: 05/21/2023]
Abstract
Chitin nanowhiskers are structured into mesoporous aerogels by using the same benign process used previously in our group to make cellulose nanowhisker aerogels. The nanowhiskers are sonicated in water to form a hydrogel before solvent-exchange with ethanol and drying under supercritical CO2 (scCO2 ). Aerogels are prepared with various densities and porosities, relating directly to the initial chitin nanowhisker content. scCO2 drying enables the mesoporous network structure to be retained as well as allowing the gel to retain its initial dimensions. The chitin aerogels have low densities (0.043-0.113 g cm(-3) ), high porosities (up to 97 %), surface areas of up to 261 m(2) g(-1) , and mechanical properties at the high end of other reported values (modulus between 7 and 9.3 MPa). The aerogels were further characterized by using X-ray diffraction, BET analysis, electron microscopy, FTIR, and thermogravimetric analysis. Characterization showed that the rod-like crystalline nature of the nanowhiskers was retained during the aerogel production process, making the aerogel truly an assembled structure of chitin nanocrystals. These aerogels also showed the lowest reported shrinkage during drying to date, with an average shrinkage of only 4 %.
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Affiliation(s)
- Lindy Heath
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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19
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Rice Husk Ash as a Renewable Source for the Production of Value Added Silica Gel and its Application: An Overview. BULLETIN OF CHEMICAL REACTION ENGINEERING & CATALYSIS 2012. [DOI: 10.9767/bcrec.7.1.1216.1-25] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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20
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Hrubesh LW, Poco JF. Processing and Characterization of High Porosity Aerogel Films. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-371-195] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractAerogels are highly porous solids having unique morphology among materials because both the pores and particles making up the material have sizes less than wavelengths of visible light. Such a unique morphology modifies the normal molecular transport mechanisms within the material, resulting in exceptional thermal, acoustical, mechanical, and electrical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant for any solid material. Special methods are required to make aerogel films with high porosity. In this paper, we discuss the special conditions needed to fabricate aerogel films having porosities greater than 75% and we describe methods of processing inorganic aerogel films having controllable thicknesses in the range 0.5 to 200 micrometers. We report methods and results of characterizing the films including thickness, refractive index, density (porosity), and dielectric constant. We also discuss results of metallization and patterning on the aerogel films for applications involving microminiature electronics and thermal detectors.
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21
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Poco JF, Coronado PR, Pekala RW, Hrubesh LW. A Rapid Supercritical Extraction Process for the Production of Silica Aerogels. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-431-297] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractSilica aerogels are a special class of porous materials in which both the pore size and interconnected particle size have nanometer dimensions. This structure imparts unique optical, thermal, acoustic, and electrical properties to these materials. Transmission electron microscopy and small angle x-ray scattering show that this nanostructure is sensitive to variations in processing conditions that influence crosslinking chemistry and growth processes prior to gelation. Recently, Lawrence Livermore National Laboratory (LLNL) has demonstrated that a Rapid Supercritical Extraction (RSCE) process can be used to prepare near-net shape silica aerogels in hours rather than days. Preliminary data from RSCE silica aerogels show that they have improved mechanical properties and slightly lower surface areas than their conventionally dried counterparts, while not compromising their optical and thermal performance.
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22
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Liebner F, Haimer E, Wendland M, Neouze MA, Schlufter K, Miethe P, Heinze T, Potthast A, Rosenau T. Aerogels from Unaltered Bacterial Cellulose: Application of scCO2
Drying for the Preparation of Shaped, Ultra-Lightweight Cellulosic Aerogels. Macromol Biosci 2010; 10:349-52. [DOI: 10.1002/mabi.200900371] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Bhupathi P, Hwang J, Martin RM, Blankstein J, Jaworski L, Mulders N, Tanner DB, Lee Y. Aerogel waveplates. OPTICS EXPRESS 2009; 17:10599-10605. [PMID: 19550455 DOI: 10.1364/oe.17.010599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Optical transmission measurements were made on 98% porosity silica aerogel samples under various degrees of uniaxial strain. Uniaxially compressed aerogels exhibit large birefringence, proportional to the amount of compression, up to the 15% strain studied. The birefringence is mostly reversible and reproducible through multiple compression-decompression cycles. Our study demonstrates that uniaxially strained high porosity aerogels can be used as tunable waveplates in a broad spectral range.
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Affiliation(s)
- Pradeep Bhupathi
- Department of Physics, University of Florida, Gainesville, Florida 32611-8440, USA.
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Pollini M, Sannino A, Maffezzoli A, Licciulli A, Nicolais L. Nonsupercritical synthesis of microporous gels. J Appl Polym Sci 2008. [DOI: 10.1002/app.28588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Balkis Ameen K, Rajasekar K, Rajasekharan T. Silver Nanoparticles in Mesoporous Aerogel Exhibiting Selective Catalytic Oxidation of Benzene in CO2 Free Air. Catal Letters 2007. [DOI: 10.1007/s10562-007-9233-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Affiliation(s)
- Alain C Pierre
- Institut de Recherches sur la Catalyse, UPR 5401 du CNRS, Université Claude Bernard Lyon1, 2 avenue Albert Einstein, 69626 Villeurbanne Cedex, France
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Schubert U. New materials by sol–gel processing: design at the molecular level. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/dt9960003343] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sun Y, Sermon PA. Surface reactivity and bulk properties of ZrO2. Part 2.—Importance of homogeneity in the stabilisation of high surface area CeO2–ZrO2aerogels. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/jm9960601025] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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SCHNEIDER MICHAEL, BAIKER ALFONS. Aerogels in Catalysis. CATALYSIS REVIEWS-SCIENCE AND ENGINEERING 1995. [DOI: 10.1080/01614949508006450] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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