Global compartmental analysis of the fluorescence decay surface of the halato telechelic polymer (n,n-dimethyl-n-[3-(1-pyrenyl)propyl]ammonio)-trifluoromethanesulfonate-end-capped poly(tetrahydrofuran)
Hermans, R × Deschryver, Fc Vanstam, J Boens, Noël Jerome, R Teyssie, P Trossaert, G Goethals, E Schacht, E #
Amer chemical soc
Macromolecules vol:28 issue:9 pages:3380-3386
The kinetic behavior of the halato telechelic polymer (N,N-dimethyl-N-[3-(1-pyrenyl)propyl]-ammonio)trifluoromethanesulfonate-end-capped poly(tetrahydrofuran) (POLYPROBE) in tetrahydrofuran is investigated by global compartmental analysis of the fluorescence decay surface. At low POLYPROBE concentrations the emission decays monoexponentially. When an analogous end-capped halato telechelic polymer without the pyrene chromophore ((N,N,N-triethylammonio)trifluoromethanesulfonate-end-capped poly(tetrahydrofuran), POLYSALT) is added to solutions containing a low POLYPROBE concentration, the emission can be fitted by a biexponential decay function. From these observations it is concluded that the second excited-state species in the POLYPROBE-POLYSALT system is POLYPROBE involved in ion aggregation due to dipole-dipole or ion-dipole interaction. At higher POLYPROBE concentrations, without added POLYSALT, a triexponential decay function is needed to describe the emission. The third excited-state species is POLYPROBE excimer, which can be formed via two pathways: either intermolecularly when a locally excited POLYPROBE encounters a ground-state POLYPROBE or intramolecularly when an aggregate of two POLYPROBE molecules rearranges. From the global compartmental analysis in which the value of one of the rate constants is scanned, it is found that the bimolecular processes are slowed down by the presence of the polymer chain, while intramolecular rearrangements are not affected.