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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 1272-1278 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Photochemical hole spectra of 1,4-dihydroxyanthraquinone in polymer matrices at liquid helium temperatures were investigated by changing the main chain structure of polymer molecules systematically. Polymer molecules adopted here were poly(ethylene-co-methacrylic acid) (EMA) and its homopolymers poly(ethylene) (PE) and poly(methacrylic acid) (PMAA). Polarity of matrices or the number density of the electric dipoles mainly localized around the methacrylic acid units are decreased in the sequence of PMAA, EMA, and PE. Remarkable matrix effects on the hole-growth profiles were observed: The holewidth in the saturated regime decreased with decreasing the polarity of the polymer matrices from 1.4 cm−1 in PMAA through 0.15 cm−1 in EMA to 0.05 cm−1 in PE. The model of the photoinduced hole broadening is proposed in relation to the nature of two-level systems of the polymer glasses which exert influence on the holewidth. Dipole–dipole coupling is possibly a dominant interaction in the present systems. The results on the annealing properties of holewidth are also discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 186 (1985), S. 923-931 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dialkyldiallylammonium salts 1a-c were prepared by quaternization of diallylamine with alkyl bromides and their polymerizability as oriented molecular assemblies in aqueous solution is discussed. Thin films of those ammonium salts on the glass wall were incubated by adding a phosphate buffer solution to yield giant spherical vesicles with diameters ranging from 10 to 100 μm. When large amounts of the ammonium salt were applied, it was necessary to add more than 5 mol-% of cholesterol in order to stabilize the resulting giant vesicles. By ultrasonication of the film-aqueous solution system, much smaller vesicles with diameters ranging from 0,03 to 0,2 μm were obtained. The stabilizing effect of cholesterol addition to the system of the small vesicles is similar to that observed for the giant vesicles. Under an inert atmosphere, the vesicles in aqueous solution were polymerized by ultraviolet irradiation. From the results of TEM and NMR spectroscopy, it was concluded that the molecules were polymerized in the vesicles without changing the profile of molecular assembly during an irradiation of 6 h. However, when the ammonium salts were dissolved homogeneously in degassed benzene, the ultraviolet irradiation polymerization did not proceed beyond a conversion of 5% under the same conditions.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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