| Abstract
| - The interaction between the cationic HTMA-PFP (Poly-(9,9-bis(6‘-N,N,N-trimethylammonium)hexyl-fluorenephenylene) bromide) and oppositely charged sodium n-alkyl sulfonate surfactants of different chain lengthshas been studied in DMSO−water solutions (4% v/v) by UV−visible absorption, fluorescence spectroscopy,fluorescence lifetimes, electrical conductivity, and 1H NMR spectroscopy. Polymer−surfactant interactionslead to complex spectroscopic behaviors which depends on surfactant concentration. At low surfactantconcentrations, the observed strong static fluorescence quenching of fluorescence seems to be associatedwith formation of aggregates between polymer chains neutralized through interaction with surfactants. Thisis supported by conductivity and by analysis of absorption spectra deconvoluted at each surfactant concentrationusing an adapted iterative method. In contrast, above the surfactant critical micelle concentration, there is astrong fluorescence enhancement, leading in some cases to higher intensities than in the absence of surfactants.This is attributed to the transformation of the initially formed aggregates into some new aggregate speciesinvolving surfactant and polymer. These changes in HTMA-PFP fluorescence as a function of n-alkyl sulfonateconcentration are important for the general understanding of polymer−surfactant interactions, and the aggregatesformed may be important as novel systems for applications of these conjugated polyelectrolytes.
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