Date of Graduation

7-2015

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

Degree Level

Graduate

Department

Mechanical Engineering

Advisor/Mentor

Huang, Po-Hao Adam

Committee Member

Jensen, David C.

Second Committee Member

Wejinya, Uche C.

Keywords

Applied sciences; Composite materials; Corrosion; Mems; Nabo particles; Novel technologies; Sensors

Abstract

The primary objective for this thesis is to contribute to the understanding of the oxide removal process for a corrosion sensing device. The goal for designing such a device is for monitoring corrosion on metallic structures. The sensing material (6.35mm x 1mm discs) of the device is composed of copper (I) oxide particles mixed in some polydimethylsiloxane (PDMS). The PDMS, “housing,” is meant for controlling the oxidation rate through the sensing material. A solvent was used to facilitate the etchant diffusion through the PDMS matrix. Toluene and acetic acid were the ideal solvent and etchant, respectively, for carrying out the oxide removal process. [1] The experimental setup used a Microsoft® LifeCam to measure the expansion of the sensing material submitted to the oxide removal process. LabVIEW™ and Vision Assistant™ where used to acquire and store the swelling data, which was then analyzed in Matlab®. There were two oxide removal processes adopted in this thesis. The first process consisted of submerging the copper (I) oxide to PDMS composite sample in toluene until it reached its known maximum growth size and then adding the etchant to carry out the oxide removal process. This process proved to be efficient and failure proof. Though the time for reaching maximum growth weighed against the oxide removal time, this process ensured a thorough oxide etching within the sensing material. The second process consisted of premixing the solvent and etchant prior to submerging the copper (I) oxide to PDMS composites. The second process proved to be faster than the first process, since the sample was not initially grown to its maximum size, with an average time constant (maximum swelling and supposedly complete oxide removal time) differed by about half the average time constant of the first process. Two different growth instances with two different time constants were observed on the graphs of the second process. These instances could be caused by the removal of the oxide which had previously stiffened the PDMS structure prohibiting the solvent from reaching certain areas of the PDMS’s matrix. Once the oxide removed, those areas were exposed permitting the solvent to have access thus causing a second distinct growth instance for the same copper (I) oxide composite sample.

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