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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Langmuir 5 (1989), S. 1288-1292 
    ISSN: 1520-5827
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 672 (1992), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 3230-3233 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Near-edge x-ray absorption fine structure spectroscopy was used to study the effect of temperature on ion pairing of a potassium salt in a modified carbonate (MC3) solution and in a poly(ethylene oxide)-potassium salt complex that used MC3 as a plasticizer. The modified carbonate was made by attaching three ethylene oxide units to the four position of ethylene carbonate. Spectra were obtained, at the K edge of potassium, over the temperature range of 25–110 °C. Studies of reference systems showed a correlation between ion pairing and white line splitting in the near-edge region of the spectra. The degree of white line splitting was used as a qualitative indicator of the degree of ion pairing as a function of temperature. The results indicate that, in both systems, the number of ion pairs increases with increasing temperature.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electroanalysis 3 (1991), S. 751-756 
    ISSN: 1040-0397
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The response characteristics of a new sensor for determining acetylcholine are reported. The sensor is based on a carbon paste electrode containing the enzymes acetylcholinesterase and choline oxidase and the electron transfer mediator tetrathiafulvalene (TTF). TTF is shown to efficiently reoxidize the reduced flavin adenine dinucleotide centers of choline oxidase. Acetylcholine calibration graphs are obtained in the range 10-6 to 10-3 M in pH 7.0 phosphate buffer, and the sensors are shown to operate efficiently at low applied potentials, where electrochemical interference due to oxidation of ascorbic acid is minimized.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 879-885 
    ISSN: 0887-624X
    Keywords: polyisocyanates ; polymer electrolytes ; metallic cation conducting polymers ; steric hindered phenols ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,6-Di-t-butylphenol and oligo(ethylene oxide) bound covalently to polyisocyanate were synthesized and characterized. The ionic conductivities of their Li, Na, and K phenolates were studied at various temperatures. The conductivities were in the range of 10-7-10-5 S/cm at 30°C. The conductivity of Na and K salts was approximately 102 greater than that of the Li salts. The t-butyl groups serve to dissociate K and Na ions from the phenoxide. The cations, therefore, are more mobile as a result increasing the conductivity. The temperature dependence of ionic conductivity suggests that the migration of ions is controlled by segmental motion of the polymer, shown by linear curves obtained in Vogel-Tammann-Fulchere plots. The polyisocyanate backbone is a rather stiff structure, however, a flexible oligo(ethylene oxide) side chain forms complexes with metal ion. Since the ion transport is associated with the local movement of polymer segments, the rigidity of the polymer backbone does not have much influence on the ion mobility.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2573-2581 
    ISSN: 0887-624X
    Keywords: single alkaline metal ion conductors ; polymer electrolytes ; antioxidation properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polysiloxanes with covalently attached oligo ethylene oxide and di-t-butylphenol (I), naphthol (II), and hexafluoropropanol (III) were synthesized. The crosslinked polymers with a hexamethylene spacer were also prepared. The ion conductivities of the Li, Na, and K salts were measured as a function of temperature. The highest conductivities for K and Na of I at 30°C were 5.5 × 10-5 and 5.0 × 10-5 S/cm, respectively, when the ratio of the ion to ethylene oxide unit was 0.014. On the other hand, Li conductivity was 8.0 × 10-6 S/cm when the ratio between Li and ethylene oxide unit was 0.019. The maximum conductivities of Li ions of II and III were in the order of 10-6 and 10-7 S/cm at 30°C, respectively. When the polymers were crosslinked by a hexamethylene residue, the ion conductivities decreased while the degree of crosslinking increased. The temperature dependence of the cation conductivities of these systems could be described by the Williams-Landel-Ferry (WLF) and the Vogel-Tammann-Fulcher (VTF) equation. The results demonstrate that ion movement in these polymers is correlated with the polymer segmental motion. The order of ionic conductivity was K+ 〉 Na+ ≫ Li+. This suggests that steric hindrance and π-electron delocalization of the anions attached to polymer backbone have a large effect on ion-pair separation and their ionic conductivities. Thermogravimetric analysis of the polymers indicated that the degradation temperature for I and II were about 100°C higher than for poly(siloxane-g-ethylene oxide). This is due to the antioxidant properties of sterically hindered phenols and naphthols. © 1993 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 2 (1991), S. 229-235 
    ISSN: 1042-7147
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A polysiloxane and an acrylonitrile-ethylene copolymer with covalently attached p-hydroquinone/benzoquinone moieties were prepared and tested as electron transfer relay systems in amperometric glucose biosensors. Using experiments involving cyclic voltammetry and stationary potential measurements, it was shown that the polysiloxane relay system can efficiently mediate electron transfer from reduced glucose oxidase to a conventional carbon-paste electrode. Sensors containing this polymeric relay system and glucose oxidase respond rapidly to low (〈0.1 mm) glucose concentrations, with steady state current responses achieved in less than 1 min. The acrylonitrile-ethylene copolymer was found to be less efficient than the polysiloxane system at mediating the electron transfer from reduced glucose oxidase to the electrode. The dependence of the sensor response on the nature of the polymer backbone is discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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