Date of Award

Spring 5-2015

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Biochemistry

School

Mathematics and Natural Sciences

Committee Chair

Paige Buchanan

Committee Chair Department

Chemistry and Biochemistry

Committee Member 2

Dr. Anthony Bell

Committee Member 2 Department

Chemistry and Biochemistry

Committee Member 3

Randy Buchanan

Committee Member 3 Department

Computing

Committee Member 4

Wujian Miao

Committee Member 4 Department

Chemistry and Biochemistry

Committee Member 5

Karl Wallace

Committee Member 5 Department

Chemistry and Biochemistry

Abstract

In this document the film composition, self-cleaning aspect, photocatalytic efficiency, and methods employed to analyze a novel photocatalytic titania-containing thin film was evaluated. A primary objective of this research project was to assess the conditions required to achieve a stable titania dispersion for the photocatalytic coating and to determine the extent to which the presence of additives contributes to this process. Modified titania dispersions were prepared and characterized via dynamic light scattering (DLS), transmission electron microscopy (TEM), fourier transmission infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Characterization details of the previous focus on the influence of polyhedral oligomeric silsesquioxane (POSS) titania modification, monomer presence, and particle identity. Various POSS derivatives, Trisilanol Isobutly POSS (TSI-POSS), Trisilanol Phenyl POSS (TSP-POSS), and Aminopropyl Isobutly POSS (API-POSS) were investigated due to the differences in functionality and sterics. Monomers, trimethylolpropane tris (3-mercaptopropionate) (TMPMP), pentaerythritol allyl ether (APE), and 1,3,5-triallyl-1,3,5-triazine-2,4,6 (1h,3h,5h)-trione (TTT) were incorporated into the stable dispersion and characterized prior to the application. A second goal was to measure the hydrophobic/hydrophilic transition of the novel photocatalytic material and to evaluate the transition performance as a function of concentrations, humidity, and film composition. Thin films were created using the modified dispersions and characterized by scanning electron microscopy (SEM), optical imaging, atomic force microscopy (AFM), and contact angle analysis. Since the thin film composition contributed to the observed efficiency of the photocatalytic process, the third goal of this research was to determine the optimum composition that permits complete degradation in a timely manner. Light conditioning and experimental analysis of the photocatalytic thin films were conducted using a novel photoreactor designed to control environmental parameters while providing the conditions necessary for titania activation to occur. Evaluation of the thin films provided CO2/VOC area ratios as a function of mustard gas simulant concentration, film composition, and relative humidity. The data acquired was used for the design and employment of novel prediction modeling software capable of forecasting the photocatalytic performance of titania containing thin films in various conditions.

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