Polymer, Vol.36, No.23, 4445-4448, 1995
Solvent Dependence of Magnetic-Field Effect in a Polymer-Linked Exciplex System
The response of pyrene-polystyrene-dimethylaniline (Py-PS-DMA) polymer (M(n)=4770) to an externally applied magnetic field has been examined in different solvents. Although the dielectric-constant (epsilon) effect is similar to that for the unlinked system, a closer look. shows an interesting dependence on the nature of the solvent mixture. In pure acetone Delta phi/phi is higher than that in a mixed solvent (tetrahydrofuran/dimethylformamide) of the same epsilon. The results have been explained on the basis of the fact that the influences of coil extension on the magnetic-held effect and the dielectric-constant effect compete with each other, resulting in different behaviours depending on the nature of the solvent mixture.
Keywords:TO-END CYCLIZATION;RADICAL ION-PAIRS;INTERMOLECULAR EXCIPLEX;DYNAMICS;LUMINESCENCE;POLYSTYRENE;DONOR