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Quantifying Fluorogenic Dye Hydration in an Epoxy Resin by Non-Contact Microwave Dielectric Spectroscopy



Sindhu Seethamraju, Jan Obrzut, Jack F. Douglas, Jeremiah Woodcock, Jeffrey W. Gilman


We investigated a chemically modified Rhodamine B dye as a sensor of local water content in dye-modified epoxy resins, where these measurements were combined with dielectric measurements to estimate the dye-water association ratio in the material. In particular, the water sensitive fluorogenic dye was covalently attached to the epoxy resin backbone. This dye becomes fluorescent only upon photo activation by ultraviolet (UV) light and its protonation in the presence of water. High-resolution non-contact microwave cavity dielectric measurements on these materials indicate a decrease of the dielectric permittivity upon photo activation. We utilize this effect to determine the average extent of hydration of the activated dye molecules. Our results suggest that fluorogenic dyes are promising for the quantification of the local water content in polymer materials, such as the technologically important problem of interfacial water in epoxy materials.
Journal of Physical Chemistry B


fluorogenic sensors, interfacial water, dielectric measurement, epoxy resins


Seethamraju, S. , Obrzut, J. , Douglas, J. , Woodcock, J. and Gilman, J. (2020), Quantifying Fluorogenic Dye Hydration in an Epoxy Resin by Non-Contact Microwave Dielectric Spectroscopy, Journal of Physical Chemistry B (Accessed May 28, 2024)


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Created March 11, 2020, Updated October 12, 2021