| AVS 64th International Symposium & Exhibition | |
| Biomaterial Interfaces Division | Monday Sessions |
| Session BI-MoM |
| Session: | Engineering a Paradigm Shift in Control of Microbes and Fouling |
| Presenter: | Daniel Barlow, US Naval Research Laboratory |
| Authors: | D.E. Barlow, US Naval Research Laboratory J.C. Biffinger, US Naval Research Laboratory C.-S. Hung, Air Force Research Laboratory L.J. Nadeau, Air Force Institute of Technology A.L. Crouch, Air Force Research Laboratory T. Zicht, Air Force Research Laboratory J.N. Russell, Jr., US Naval Research Laboratory W.J. Crookes-Goodson, Air Force Research Laboratory |
| Correspondent: | Click to Email |
Fungal and bacterial fouling on military aircraft is a problem that can lead to polyurethane top coat deterioration and pose health hazards to personnel; the phasing out of hexavalent chromium in coatings is expected to worsen fouling problems. Thus, better understanding of the relevant microbiological interactions with polyurethanes is required to identify new ways to inhibit fouling and associated affects. We have screened over 400 aircraft isolates for polyurethane degradation, with Cryptococcus strains among the most aggressive polyurethane degraders. These strains were further characterized for their capability to metabolize and grow on expected hydrolysis products from polyester components of the polymers, showing that fungal growth occurs to varying degrees on the metabolites. Gas chromatography also showed that microbes metabolize polymers and hydrolysis products to CO2. Polymer metabolization to CO2 results in bulk polymer loss and optical profilometry confirmed that fungal cells steadily “eat” trenches into solid polyurethane films over time. Initial polyurethane film degradation processes at the micro and nano scales were analyzed by confocal Raman and AFM-IR (combined AFM and infrared spectroscopy). These results showed varying, non-uniform degradation events among cells, indicating that variations in single cell physiology play roles in early stage degradation. The spectroscopic results are consistent with lipase activity as the primary driver of degradation.