Date of Award

Spring 5-14-2016

Degree Type

Thesis

Degree Name

MS Chemistry

Department

Chemistry and Biochemistry

Advisor

Sergiu M. Gorun, Ph.D

Committee Member

James E. Hanson, Ph.D

Committee Member

Wyatt R. Murphy, Ph.D

Keywords

Photocatalyst, Self-cleaning coating, Singlet oxygen, Phthalocyanine, Titanium dioxide, visible light

Abstract

A new photocatalytic composite powder incorporated into a siloxane epoxy polymer has been shown to yield a highly efficient self-cleaning coating. The composite, which makes greater use of light in the visible/near-infrared (NIR) region, was prepared by coating a nano-particle photocatalytic TiO2 with 3% w/w of F64PcZn photosensitizer resulting in a dark green powder. The F64PcZn/P25 TiO2 composite exhibited a greater photo-induced degradation of methyl red, a model surface contaminant, compared to traditional nano-particle photocatalytic TiO2. Singlet oxygen (1Δg 1O2), generated form the F64PcZn, is believed to be the primary species responsible for the observed photo-activity. The durability of the coating was evaluated by electrochemical impedance spectroscopy (EIS) due to the potential for unwanted photo-oxidation of the polymer by the photocatalytic material. After 11 weeks of atmospheric sunlight exposure, the coating containing the composite displayed a small drop in impedance value but still remained >10 GOhm cm2, indicating the formation of a strong barrier that is able to protect the underlying metal surface. A control coating containing uncoated nano-particle photocatalytic TiO2 dropped slightly lower to ~10 GOhm cm2. The novelty of the disclosed composite for producing self-coatings was recognized by the US Patent Office, US 9,260,630 B2.

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