Exciton movement in polymer chains

This picture of the energy transfer is simplistic, as in a real polymer the chromophores will have alignments which are controlled by the conformations which the chain may adopt. As discussed in earlier chapters, increasing the temperature may introduce local gauche conformations and these will have a different 

The migration of an exciton along the polymer chain is much faster than the diffusion together of dilute small molecules in a mobile solvent. Furthermore, the migration is not dependent on translational diffusion (though it is dependent on internal rotation) and so the reaction may well be able to take place in a solid, which is not the case for separated small molecules. 

In this example, the polymer chain acts rather like the antenna of a television set, picking up the signal of the incident photon and transmitting it to the site of activity. Consequently, the phenomenon has been called the antenna ect. 

Interestingly, photosynthesis makes use of a similar process. The photons incident on the leaf are harvested by stacks of chlorophyll, which then allow the energy to migrate through them to the site of chemical reaction in a slightly different chlorophyll molecule. 

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