Nondestructive Early Detection of Metal Corrosion in Pigmented Coatings with Fluorescent Smart Materials (First-year Report)

Abstract : Fluorescent dyes were studied in an effort to develop molecules suitable to signal the onset of metal corrosion under a paint or coating. Rhodamine B and fluorescein were chemically modified to determine the effect of steric hindrance and electron withdrawing/donating substituents on the selective binding of these dyes to various metals. Rhodamine B and fluorescein were converted into the corresponding hydrazide to provide a precursor material. The hydrazides were then reacted with various diphenyl and dialkyl ketones to determine the impact of bulky groups on dye-metal binding. Electronic effects were probed as the hydrazide precursors were reacted with various aldehydes that contained substituted phenyl rings. Fluorescence measurements were used to determine the impact of each substitution on dye-metal binding efficiency and selectivity.