title: Formation and dissociation of the acridine orange dimer as a tool for studying polyelectrolyte-surfactant interactions.
abstract: Steady-state and time-resolved fluorescence and UV-vis techniques were used to study the formation and dissociation of acridine orange dimer in order to investigate hyaluronan-acridine orange, hyaluronan-CTAB (cetyltrimethylammonium bromide), polystyrenesulfonate-acridine orange, and polystyrenesulfonate-CTAB interactions in aqueous solution. Steady-state and time-resolved fluorescence and the dimer:monomer absorbance ratio of acridine orange (AO) were used to determine dimer formation on polymer chains of polyelectrolytes. Acridine orange clearly formed dimers on polystyrensulfonate chains as well as on hyaluronan, but we show that the electrostatic interaction is much weaker in the case of hyaluronan. After the addition of surfactant, we observed an enhancement of fluorescence intensity, indicating the dissociation of AO dimers into monomers and the replacement of acridine orange on polymer chains by surfactant molecules. Importantly, we show that surfactant molecules bind to polymer chains before the critical micelle concentration is reached and form the so-called "bottle-brush" structure.
authors.affiliation: Brno University of Technology, Faculty of Chemistry, Institute of Physical and Applied Chemistry and Materials Research Centre , Purkyňova 464/118, 612 00 Brno, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Mondek
authors.forename: Filip
authors.initials: F
authors.lastname: Mravec
authors.forename: Tereza
authors.initials: T
authors.lastname: Halasová
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Hnyluchová
authors.forename: Miloslav
authors.initials: M
authors.lastname: Pekař