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  • Polymer and Materials Science  (12)
  • emission anisotropy  (1)
  • photosensitizers  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Journal of Photochemistry and Photobiology B: Biology 2 (1988), S. 109-122 
    ISSN: 1011-1344
    Schlagwort(e): Candida phototoxicity test. ; DNA reactions ; Pyrrolocoumarins ; laser flash photolysis ; photohaemolysis ; photosensitizers ; phototoxicity
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of sol gel science and technology 8 (1997), S. 895-899 
    ISSN: 1573-4846
    Schlagwort(e): luminescence ; pyranine ; sol-gel ; hybrid coatings ; emission anisotropy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The sensitivity of the pyranine fluorescence to protonation/deprotonation is used to follow modifications in cured sol-gel thin films. The acid concentration in the sol-gel solution is varied for TEOS-based coatings and a series of organically modified silanes Si(OR)3R′ are added to the TEOS solution. The concentration of the organically modified silane is varied as well as the chain length of the alkylgroup (R′). The stationary fluorescence measurements show that the equilibrium between the protonated and the deprotonated form of pyranine changes depending on the type of silica matrix. The deprotonated form is dominant in the cured SiO2 films and the protonation/deprotonation ratio of pyranine is constant for the different acid concentrations used. The protonated form becomes dominant as the concentration of Si(OR)3R′ is increased and as the alkyl chain length (R′) of the organically modified silanes is augmented. Emission anisotropy measurements of pyranine in the same coatings show that the rotational freedom of the molecule changes due to modifications in the cages for the TEOS-based coatings. These modifications are produced by the acid concentration used to prepare the coatings. An increase in the rotational freedom of pyranine is observed in the TEOS-Si(OR)3R′ systems.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 85-106 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Different modes of interaction between the realm of photochemistry and photophysics and the domain of polymer chemistry are discussed. A distinction between photoinitiation and photopolymerization is drawn on the basis of the role of the excited state either in the chain starting or chain-growing process. Attention is drawn to specific properties or problems in the photochemistry and photophysics of macromolecules. The influence of neighbouring groups, high local concentrations etc. are discussed in relation to polymer transformation and excimer formation.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 13 (1985), S. ix 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Dipeptides of the aromatic fluorescent amino acid, pyrenylalanine, are studied using both stationary and transient fluorescence techniques. Since the conformational transitions of the peptide chain are slow compared to the decay of the pyrene excited state, both ground state conformations, adopted by the peptide, i.e., C5 and C7, can be monitored separately. Kinetic models are proposed to describe the molecular dynamics of the peptide chain as probed by the intramolecular excimer formation between both pyrene chromophores. These kinetic schemes explain the influence of solvent, chain chirality, main chain-side chain interactions, and nature of the protecting groups on the emission spectrum and the fluorescence decay profile of these model peptides. These schemes also provide a tool to calculate rate constants of conformational transitions and excimer formation. By comparing the kinetic and thermodynamic parameters of the various compounds, the influence of a structural modification on the molecular dynamics of the peptide chain is determined.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 13 (1975), S. 215-225 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The kinetics of the photoreduction of benzophenone and the reductive photopolymerization of diaryl ketones are closely interrelated. The photoreductive polyrecombination presents the characteristics of a polycondensation, namely, an increase in molecular weight with reaction time. In the absence of side reactions, benzophenone and diketone Ia show identical behavior toward hydrogen abstraction, as is reflected in the di-bis rate constants of hydrogen abstraction.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 13 (1975), S. 227-252 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The irradiation of nonconjugated bichromophoric systems, diaryl ketones, with ultraviolet light in the presence of hydrogen donors, such as isopropanol or bisbenzhydrol, yields high polymers. Two series of arylketones were investigated, namely bisbenzophenones and bisketotriazoles. The cage reaction, which arises from the cross combination between the acetone ketyl and bisbenzophenone ketyl radicals, was estimated to be very small but may constitute a chain termination reaction in the photopolymerization in isopropanol. The photopolymerization of bisdiketone-dihydrol systems was found to yield polymers with much higher molecular weights than those obtained from the photopolymerization of bisdiketone-isopropanol systems. The photolysis of some binary mixtures of aromatic diketones in the presence of isopropanol yielded statistical copolypinacols. In some favorable cases, the NMR spectrum of the copolymer obtained showed three distinct linkages and from the infrared spectrum intensities the copolymers composition and the number average length of the sequences may be determined.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 6 (1968), S. 547-550 
    ISSN: 0449-2986
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 9 (1971), S. 777-780 
    ISSN: 0449-2986
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 10 (1972), S. 669-673 
    ISSN: 0449-2986
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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