title: pH dependence of the interaction between rhodamine B and the water-soluble poly(sodium 4-styrenesulfonate).
abstract: The binding of rhodamine B (RB) to the polyanion containing aromatic groups poly(sodium 4-styrenesulfonate) (PSS) is studied by separation and spectroscopic techniques at pH between 2 and 7. Significant binding is found at pH below 5, together with a red-shift of the RB maximum of absorbance to 564 nm, and RB fluorescence quenching. The dependence of the pH is related with protonation of RB molecules. Fluorescence quenching is a consequence of a more hydrophobic environment and may occur on territorially or site-specifically bound molecules, and/or on self-aggregated molecules in a hydrophobic polymer domain. Remarkably, the basicity of RB is increased by the influence of the polymer.
authors.affiliation: Instituto de Química, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile. imorenovilloslada@uach.cl
authors.forename: Ignacio
authors.initials: I
authors.lastname: Moreno-Villoslada
authors.forename: Marlén
authors.initials: M
authors.lastname: Jofré
authors.forename: Víctor
authors.initials: V
authors.lastname: Miranda
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Gonzalez
authors.forename: Tamara
authors.initials: T
authors.lastname: Sotelo
authors.forename: Susan
authors.initials: S
authors.lastname: Hess
authors.forename: Bernabé L
authors.initials: BL
authors.lastname: Rivas