Fluorescence studies of the binding of anionic derivatives of pyrene and fluorescein to cationic polyelectrolytes in aqueous solution

Abstract

The electrostatic binding of the anionic probes pyrenetetrasulfonic acid (4-PSA) and 6-carboxyfluorescein (6-CF) to poly(allylamine hydrochloride) (PAH), poly(diallyldimethylammonium chloride) (PDADMAC), and DADMAC-acrylamide (AAM) copolymers in aqueous solution has been investigated by fluorescence spectroscopy. Binding of the probes to the polyelectrolytes causes changes in their fluorescence emission and excitation spectra, which allows conclusions to be drawn about their binding mechanisms. 4-PSA forms excimers in the presence of PAH or PDADMAC, whereas the presence of polyelectrolyte in 6-CF solutions induces fluorescence self-quenching of 6-CF. Through measurement of the 4-PSA excimer ..