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  • 1
    Electronic Resource
    Electronic Resource
    Structure of organic aerogels. 1. Morphology and scaling (1993)
    s.l. : American Chemical Society
    Macromolecules 26 (1993), S. 5487-5493 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00072a029
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    SAXS investigations on organic aerogels (1991)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 24 (1991), S. 771-776 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Structural properties of organic aerogels were studied by ultra-small-angle X-ray scattering (USAXS) at the Synchrotron Radiation Laboratory HASYLAB at DESY, Hamburg, Germany. The organic aerogels were synthesized from the base-catalyzed sol–gel polymerization of resorcinol with formaldehyde (RF) followed by a supercritical drying process. RF aerogels are low-density materials with a solid matrix composed of interconnected colloidal-like particles. Scattering experiments were carried out using a crystal camera optimized for ultra-small-angle X-ray scattering with synchrotron radiation. The measured SAXS profiles revealed a scattering power depending upon synthetic conditions of the gels. RF aerogels were found to be homogeneous at length scales greater than 20 nm. From Guinier plots, radii of gyration Rg of 3–20 nm were computed. Rg appears to be a measure of the pore (cell) size. Although fractal silica aerogels show similar characteristics, fractal behavior of the organic aerogels is uncertain. These materials are best described as random aggregates of smooth colloidal like particles with open-cell porosity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889890011815
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  • 3
    Electronic Resource
    Electronic Resource
    Capacitive deionization of NH4ClO4 solutions with carbon aerogel electrodes (1996)
    Springer
    Journal of applied electrochemistry 26 (1996), S. 1007-1018 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A process for the capacitive deionization of water with a stack of carbon aerogel electrodes has been developed by Lawrence Livermore National Laboratory (LLNL). Unlike ion exchange, one of the more conventional deionization processes, no chemicals are required for regeneration of the system. Electricity is used instead. An aqueous solution of NH4ClO4 is pumped through the electrochemical cell. After polarization, NH in4 su+ and ClO in4 su− ions are removed from the water by the imposed electric field and trapped in the extensive cathodic and anodic double layers. This process produces one stream of purified water and a second stream of concentrate. The effects of cell voltage, salt concentration, and cycling on electrosorption capacity have been studied in detail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242195
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Rate effect on lithium-ion graphite electrode performance (1996)
    Springer
    Journal of applied electrochemistry 26 (1996), S. 1161-1167 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The electrochemical performance of lithium-ion graphite electrodes with particle diameter in the range of 6–44 µm was evaluated at different discharge (intercalation)/charge (deintercalation) rates (C to C/60). The electrode capacity depends on both the average particle size and rate. With a simple rate programme, the electrode performance is dependent on the cycling rate. The capacity of small graphite particles (6 µm) at C/2 rate was 80% of that achieved at C/24 rate (∼372 mAh g−1). The capacity of large graphite particles (44 µm) obtained at fast rates (C/2) was only 25% of that obtained under near-equilibrium conditions (C/24). The electrode capacity, however, is nearly independent of the charge rate when the electrode is fully intercalated using a modified rate programme containing a constant-voltage hold at 0.005 V (vs Li+/Li) for several hours. The electrochemical behaviour is related to the physicochemical properties of the graphite particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243741
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  • 5
    Electronic Resource
    Electronic Resource
    Organic aerogels from the polycondensation of resorcinol with formaldehyde (1989)
    Springer
    Journal of materials science 24 (1989), S. 3221-3227 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer “clusters”. The covalent crosslinking of these “clusters” produces gels which are processed under supercritical conditions to obtain low density, organic aerogels ( ⩽ 0.1 g cm−3). The aerogels are transparent, dark red in colour, and consist of interconnected colloidal-like particles with diameters of approximately 10 nm. The polymerization mechanism, structure and properties of the resorcinol-formaldehyde aerogels are similar to the sol-gel processing of silica.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01139044
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Imaging aerogels at the molecular level (1992)
    Springer
    Journal of materials science 27 (1992), S. 4341-4349 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Aerogels are a special class of open-cell foams that have an ultrafine cell/pore size (〈50 nm), high surface area (400–1000 m2 g−1), and an ultrastructure composed of interconnected colloidal-like particles or polymeric chains with characteristic dimensions of 10 nm. The purpose of this paper is to directly image a series of resorcinol-formaldehyde (RF) and silica aerogels by high resolution transmission electron microscopy (HRTEM). A new vertical replication technique allows us to examine aerogels at the molecular level in situ so that differences in polymeric and colloidal aerogels can be visualized. Such information is crucial for nano-engineering the structure and properties of these novel materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00541564
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    Paper (German National Licenses)
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