Al~tracl--The efficiency of triplet energy transfer from the benzophenone group to naphthalene has been studied in a series of copolymers styrene-vinylbenzophenone, either as films or in glassy solutions at 77 K. Energy migration has been shown to be efficient in both cases. For a given copolymer, H
Energy migration and transfer in polymer systems
β Scribed by A.M. North; M.F. Treadaway
- Publisher
- Elsevier Science
- Year
- 1973
- Tongue
- English
- Weight
- 729 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0014-3057
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β¦ Synopsis
Theoretical treatments of singlet energy transfer are reviewed with the objective of determining the expressions most relevant for polymeric systems. Observations of singlet energy transfer from 1,3 diphenyl oxazole to 1,4 di[2-(4-methyl 5-phenyl oxazolyl)]-benzene, anthracene and benzophenone confirm that the F~Srster relationships are valid for dilute solutions of these small molecules.
For a polymer donor in which there exists spectral overlap in absorption and emission, there is the possibility of energy migration along the chain. Under these conditions, and where acceptor diffusion may be important, it is found that relationships due to Yokota and Tanimoto are the most useful in both fluid and polymeric environments. Coefficients for migration of singlet energy down chains of poly(N-vinyl carbazole), poly(2-vinyl) naphthalene) and copolymers of N-vinyl carbazole with methyl acrylate have been evaluated. They are consistent with a model in which energy is transferred by a random walk series of F/Srster interactions between spectroscopically active nearest neighbours.
π SIMILAR VOLUMES
Studies have been made of energy migration and transfer in dilute solutions of poly(phenylacetylene). In fluid media, "down-chain" energy migration is very efficient (being limited only by chain length in the system studied); however, in a rigid matrix, the energy migration rate is significantly low
The emission spectra of polyaeenaphthylene (PA&T) and polyvinyluaphthalene (PVN) tihus and solutions have heen compared at room temperature and 77Β°K. In organic glasses at 77'K, normal fluoresceuee and phosphorescence are observed for both polymers. Quenching of PAcN phosphorescence by piperylene in
Energy transfer has been shown to occur from triplet polyvinylbenzophenone to naphthalene by an exchange mechanism at liquid nitrogen temperature. The radius of the Terenin "critical sphere" is much larger for the polymer containing naphthalene (29.3,) than for mixtures benzophenonenaphthalene in or