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  • 1
    Electronic Resource
    Electronic Resource
    Improved analysis of ionic conductivity relaxation using the electric modulus with a Cole–Davidson distribution (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 5128-5132 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The empirical response function introduced by Cole and Davidson for the analysis of dielectric relaxation in the frequency domain has been used in an analogous way to reanalyze ionic conductivity relaxation using the electric modulus representation. The fitting of data for ionic relaxation in AgPO3, 0.1AgI-0.9AgPO3, and 0.4Ca(NO3)2-0.6KNO3 originally fit using a Kohlrausch–Williams–Watts response function has been considerably improved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347052
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  • 2
    Electronic Resource
    Electronic Resource
    Ionic conductivity in poly(propylene glycol) complexed with lithium and sodium triflate (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 681-690 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Conductivity and viscosity measurements have been made for poly(propylene glycol)-MCF3SO3 (M=Li, Na) complexes in order to examine more closely the Vogel–Tammann–Fulcher (VTF) empirical relationship which has been found in previous reports to provide a good fit to the experimental data. Further, a dynamic bond percolation model of ion conduction in polymer electrolytes has predicted VTF behavior and an inverse relationship between molar conductivity and viscosity or Walden "rule'' behavior. We find that deviations occur from both the VTF and Walden empirical relationships and propose a modest alteration in the form of the dynamic percolation model for ions moving in polyether systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.462453
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  • 3
    Electronic Resource
    Electronic Resource
    Dielectric and conductivity relaxation in poly(propylene glycol)–lithium triflate complexes (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 6323-6329 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The electric modulus representation is used to display conductivity and dielectric relaxation occurring in poly(propylene glycol)-4000 (PPG) complexed with LiCF3SO3, as the ether oxygen to lithium (O:Li) ratio is varied from 300:1 to 12:1. The frequency range covered is 10 to 107 Hz. Results are obtained for temperatures above the glass transition temperature appropriate for each PPG–LiCF3SO3 complex. For O:M=300:1, the conductivity peak and the α and α' relaxation are clearly resolved. As the concentration is increased, there is a coupling between the structural and the conductivity relaxations; the various peaks begin to overlap. The coupling is greatest for an O:Li ratio in the range 30:1 to 12:1, where the highest conductivity is measured. Below room temperature, the 30:1 complex has the highest conductivity, above room temperature the 12:1 complex has the highest. At any particular temperature there is a concentration above which the conductivity drops. This drop is due to reduced ion mobility resulting from a dramatic increase in viscosity to values above ∼100 poise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460420
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  • 4
    Electronic Resource
    Electronic Resource
    A 7Li nuclear magnetic resonance study of LiCF3SO3 complexed in poly(propylene-glycol) (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 1803-1811 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: 7Li nuclear magnetic resonance (NMR) linewidths and spin–lattice relaxation times for poly(propylene-glycol) complexed with a range of concentrations of LiCF3SO3 are reported over the temperature region from 205 to 405 K. Calculations suggest that the spin–lattice relaxation mechanism is caused by the interaction between the 7Li (I=3/2) quadrupole moment and fluctuations in the surrounding electric field gradients, whereas the line shapes are influenced by both the dipolar and quadrupolar interactions. The motional parameters reported indicate that ion–polymer or ion–ion interactions are important in determining the Li+ cation mobilities. This is reflected in the lengthening of the correlation time with increase in Li+ ion concentration which suggests a decreased mobility for the cations resulting from a transient coordination of the cation to the polymer matrix or ion aggregation. Also, the activation energies in this study (∼0.24 eV) are in agreement with values obtained from recent pulsed field gradient studies suggesting that the NMR techniques employed in this study are approriate methods for probing the dynamics of ion transport on a macroscopic scale in these materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459954
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  • 5
    Electronic Resource
    Electronic Resource
    Ion pairing effects in poly(propylene glycol)–salt complexes as a function of molecular weight and temperature: A Raman scattering study using NaCF3SO3 and LiClO4 (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 6862-6867 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The symmetric stretch modes for the anions in poly(propylene glycol) (PPG) complexed with NaCF3SO3 and LiClO4 at an ether oxygen of alkali metal cation ratio of 16:1 have been studied as a function of the molecular weight of PPG and temperature using Raman spectroscopy. The splitting of these modes has been analyzed in terms of "free'' anions and ion pairs. We have observed that the number of ion pairs increases with increasing molecular weight and increasing temperature. The effect is greater in the PPG–NaCF3SO3 complex than in the PPG–LiClO4 complex. We have found a simple exponential relationship for the number of free anions in a master-plot representation using a shift factor T* which increases with increasing molecular weight. These results are discussed in terms of the entropy and energetics of polymer–salt systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460265
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  • 6
    Electronic Resource
    Electronic Resource
    Elastic and dynamic properties of polymer electrolytes: A Brillouin scattering study of poly(propylene glycol)–NaCF3SO3 complexes (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 655-662 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In the present study of ion conducting polymers we demonstrate how light scattering can be used to obtain information about the elastic properties and the local intrachain mobility, which are essential characteristics of a high performance polymeric solid electrolyte. Brillouin scattering has been applied in studies of sodium triflate (NaCF3SO3)–poly(propylene glycol) (PPG) complexes of concentrations O:M=5:1, 8:1, and 16:1, where O:M is the backbone oxygen to sodium ratio. From the spectra sound velocity and absorption data were obtained. The acoustic data reveal structural relaxation processes associated with local translational (and orientational) intrachain motions of the polymer segments. The characteristic relaxations times τ were determined and found to be strongly dependent on the concentration of the dopant salt. This is because the dissociated ions act both as crosslinks betwen polymer chain segments and as "free'' ions available for conduction. Therefore, as the concentration of dissociated ions increases the intrachain mobility is slowed down (τ increases) due to increased crosslinking. The effect is demonstrated in the hypersonic velocity dispersion curve and in the absorption peak which both shift to higher temperatures with increasing salt concentration. The shift correlates with the increase in the glass transition temperature as salt is added to the polymer. It also correlates, at least at low salt concentrations, with the concentration of dissocated ions and with the conductivity. It can be concluded that the motions of free ions responsible for charge transport are strongly coupled to the intrachain motions of the polymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457171
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  • 7
    Electronic Resource
    Electronic Resource
    Furfuryl and Thenylalkylamines from Schiff Bases1,2 (1949)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 71 (1949), S. 703-705 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01170a091
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  • 8
    Electronic Resource
    Electronic Resource
    Substituted Sulfaquinoxalines. I. The Isolation and Synthesis of 3-Hydroxy-2-sulfanilamidoquinoxaline and of Related Quinoxalines (1946)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 68 (1946), S. 1035-1039 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01210a038
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  • 9
    Electronic Resource
    Electronic Resource
    The Chemistry of Vitamin E. XVIII. Condensation of Phenols and Hydroquinones with Allylic Alcohols, Allylic Halides, and Conjugated Dienes1 (1939)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 61 (1939), S. 2615-2618 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01265a014
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  • 10
    Electronic Resource
    Electronic Resource
    2,3-DIAMINOQUINOXALINE (1946)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 68 (1946), S. 2121-2121 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01214a524
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