Transport and diffusion of fluorescent probes in nanoporous materials

HODAK, JOSE HECTOR; ZAMBRANO GARCIA ISKRA NICOLE; GALO J. A. A. SOLER-ILLIA; ESTEFANIA GONZALEZ SOLVEYRA

Ciudad Universittaria CABA

Workshop; Currenttrendsinspectroscopyforbioandnanosciences; 2023

Facultad de ciencias Exactas y Naturales UBA / INQUIMAE CONICET

The understanding of the transport properties within the mesopores of Titania is crucial to take advantage of these materials in separations chemical sensors and catalysts. In this talk I will present the results of Fluorescence Correlation spectroscopy studies that reveal how the surface charge of the mesopore´s wall affects the restricted diffusion of fluorescent probes. It was found that positive and neutral dyes Nile Red and Rhodamine 6G, that are hydrophobic, tend to have effective diffusion coefficients at least one order of magnitude smaller than that for the negatively charged dye sulforhodamine B. Transport of these dyes reflect the mechanism of trap-and-diffuse, where diffusion is interrupted by ocassional strong adsorption events.As the pH increases the desorption of the negative dyes tends to be facilitated and the fraction of the dye that is free to diffuse increases.