Date of Award

12-2013

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Polymers and High Performance Materials

Committee Chair

James Rawlins

Committee Chair Department

Polymers and High Performance Materials

Committee Member 2

Sergei Nazarenko

Committee Member 2 Department

Polymers and High Performance Materials

Committee Member 3

Daniel Savin

Committee Member 3 Department

Polymers and High Performance Materials

Committee Member 4

Derek Patton

Committee Member 4 Department

Polymers and High Performance Materials

Abstract

The successful measurement and prediction of material lifetimes is of high importance for proper maintenance on metal infrastructures for prevention of asset loss through corrosive processes. Current testing protocols include mismatched accelerated weathering techniques in combination with visual corrosion detection that consume substantial amounts of time and resources and often lead to inaccurate extrapolation to natural conditions. For corrosion science and engineering to evolve further, accurate and early detection methods of efficiently evaluating materials are necessary. Fluorescence spectroscopy is one established non-destructive analytical technique that is highly sensitive and selective to a variety of metal ion species and chemical environments (pH, polarity etc.). Our lab has adopted the use of fluorescence for evaluation and screening of coated substrates for early detection of corrosion in advance of serious metal visual and/or physical damage. The use of various environmentally sensitive fluorescent molecules doped in thermoplastic polyepoxides for detecting water, chloride ions, metal ions (Fe3+, Fe2+, Al3+), and pH have and can be further used to quantify corrosion events and develop an understanding of ion migration and pre-corrosion events and kinetics. Fluorescence emissions monitored versus time potentially yields rate and/or kinetic data and quantifiable correlations between fluorescence response and undercoating pre-macroscopic corrosion. Our results can be utilized for earlier corrosion detection and testing protocols in combination with real time corrosion indicators. Several Fe2+ and Fe3+ specific fluorophores were evaluated for their efficacy as possible in situ corrosion indicators on ferrous substrates. Differentiation of Fe2+ and Fe3+ will allow for improved understanding of corrosion mechanisms.

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