In this study we report on the interfacial kinetic behavior of the widely used laser dye Rhodamine 6G in two different matrices frequently used for dye immobilization in fluorescence sensing applications. The water content of Nafion membranes and Silica Gel has been shown to be the critical parameter which determines the probe motion. Fluorescence anisotropy measurements indicate a free rotation of the R6G in wet and dry Nafion even through this cationic dye is held electrostatically within the water pores of the system. These results indicate that in Nafion the interfacial microviscosity of the water pore increases as water is removed but the dye position does not changes. Conversely in the case of silica gel the R6G is initially hindered in its motion when the water content is high but becomes free to rotate as the gel is dehydrated. This indicates that the level of water within the sol gel pore determines the strength of the interaction between the charged surface and the rhodamine 6G.

Date Published: 8 May 1995
PDF: 8 pages
Proc. SPIE 2388, Advances in Fluorescence Sensing Technology II, (8 May 1995); doi: 10.1117/12.208499

Published in SPIE Proceedings Vol. 2388:
Advances in Fluorescence Sensing Technology II
Joseph R. Lakowicz, Editor(s)