External and internal quenching in photochemical reactions of vinylbenzophenone-vinyl ferrocene copolymers: The problem of triplet energy transfer
✍ Scribed by G. Sánchez; R. Knoesel; G. Weill
- Publisher
- Elsevier Science
- Year
- 1978
- Tongue
- English
- Weight
- 332 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0014-3057
No coin nor oath required. For personal study only.
✦ Synopsis
The quantum yield of the photochemical reaction of the benzophenone group, either free or bound to a macromolecular chain in polyvinylbenzophenone, with a proton donor (isopropanol) has been measured in the absence and in the presence of an efficient triplet acceptor (Ferrocene), either free (external) or copolymerized (internal quenching). From an analysis of the quantum yields and Stern-Volmer constants using the proper local concentration, it is concluded that energy migration along the polymer chain is negligible in this system at the time scale of the triplet life-time (~ 10 -7 sec). Re-examination of data of Luk~i~ et al. on polyvinylphenylketone, taking in account the local concentration, shows that in this last system energy migration is however efficient even with a shorter triplet life-time.