pH dependence of the interaction between rhodamine B and the water-soluble poly(sodium 4-styrenesulfonate).
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.
Moreno-Villoslada
Ignacio
I
Instituto de Química, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile. imorenovilloslada@uach.cl
Jofré
Marlén
M
Miranda
Víctor
V
Gonzalez
Rodrigo
R
Sotelo
Tamara
T
Hess
Susan
S
Rivas
Bernabé L
BL