Publication Date


Document Type


Committee Members

Jason Deibel (Other), Brent Foy (Committee Chair), Wendy Goodson (Committee Member), Chia-Suei Hung (Committee Co-Chair)

Degree Name

Master of Science (MS)


Current United States aircraft are equipped with a multitude of protective coatings on the interior and exterior of the vehicle, ultimately enhancing their ability to ensure a safe and effective mission. Aircraft, over the course of their lifetime, will experience impact, corrosion, weathering, and microbial damage to its defensive structures, rendering it vulnerable to attacks. Damaged coatings are then repaired on the aircraft once detected in inspection or replaced in accordance to the lifecycle of the material on the aircraft. However potentially harmful threats such as bacteria are not considered by the Air Force to be dangerous. Therefore, the purpose of this study was to analyze the impact and potential biodegradation properties of microbial colonies on polyurethane film. Using Infrared Spectroscopy, the results of this research effort show chemical peak amplitude corresponding to the polyurethane spectra significantly decreased when in the presence of Cryptococcus laurentii after a week time trial. Similarly, changes in surface area and volume measurements via laser confocal microscopy coincide with chemical peak loss results, supporting spectroscopic analysis. Weight measurements of experimental samples showed no significant linkage between chemical cleaving and mass loss underneath the biofilm. Additionally, other modalities such as Ultrasound, Scanning Electron Microscopy, and Thermography were used for potential microbial detection capabilities as well as 3D structural analysis; the results do not reinforce previous spectroscopic data. This research demonstrated that Infrared Spectroscopy could reliably detect regions of localized polyurethane degradation, although the technique is laborious and time consuming. Further evaluation of microbes using the aforementioned systems is needed to determine and/or optimize suitable detection methods for field application and intra-topographical structures underneath the sampled biofilm.

Page Count


Department or Program

Department of Physics

Year Degree Awarded


Included in

Physics Commons