title: The change in excited-state proton transfer kinetics of 1-naphthol i micelles upon the binding of polymers: The influence of hyaluronan hydration.
abstract: The fast deprotonation of 1-naphthol was studied in aqueous solution and in polymer-cetyltrimethylammonium bromide (CTAB) mixtures using picosecond fluorescence spectroscopy to study the influence of hyaluronan hydration in polymer-surfactant interactions. The aqueous micelle solution showed the expected change of proton transfer rate around the reported critical micelle concentration (∼1 mM). The proton transfer rate dependence on CTAB concentration in the hyaluronan-CTAB and polystyrenesulfonate-CTAB systems differed significantly from that in the aqueous micelle solution. The dynamic study of excited state proton transfer (ESPT) revealed the significant influence of hyaluronan hydration in CTAB micelles. When hyaluronan-CTAB aggregates were formed at the CTAB concentration of 0.5mM, a tenfold decrease in the rate of deprotonation was observed when compared to polystyrenesulfonate-CTAB aggregates due to hyaluronan hydration. In 2mM CTAB-hyaluronan aggregates, the rate of deprotonation was found to be almost two times faster than in the 2mM CTAB or polystyrenesulfonate-CTAB system. Furthermore, the study of excited-state proton transfer of 1-naphthol confirmed that hyaluronan hydration layer penetrates into the micelle and changes the emission characteristics of 1-naphthol.
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. Electronic address: xcmondek@fch.vutbr.cz.
authors.forename: Jakub
authors.initials: J
authors.lastname: Mondek
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: Miloslav
authors.initials: M
authors.lastname: Pekař
keywords: Excited-state proton transfer; Fluorescence; Hyaluronan; Hydration