Traditional coatings for hindering fungal growth are environmentally hazardous. As regulations become increasingly stringent, environmentally benign coating materials are becoming more prevalent. However, due to these new, lower-toxicity coating materials, the growth of mold, mildew, and other fungi is beginning to cause detrimental effects on materials. There is an urgent need to develop an understanding of fungal survival and material degradation mechanisms on nonresistant coating materials and to explore possible solutions to mitigating or eliminating fungal growth and biocorrosion. The primary goal of this research project is to explore the fungal degradation mechanisms of coating materials by developing an approach combining laser-induced breakdown spectroscopy (LIBS), mass spectrometry (MS), and Raman spectroscopy. A thorough understanding of the degradation mechanisms will provide pathways to reduce or avoid this type of biocorrosion. To accomplish the goal, research efforts will focus on the following four objectives: 1) track the transfer of critical nutritional elements used for fungal survival and their compound forms; 2) determine the fungal metabolic products causing corrosion and their formation pathways; 3) monitor the formation of fungal biofilms in real time; and 4) understand the degradation mechanisms and explore possible pathways to avoid fungal corrosion.
In this project, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and laser-assisted direct-analysis-in-real-time mass spectrometry (LA-DART-MS), in conjunction with LIBS and Raman spectroscopy, will be used to understand the mechanisms of fungal survival, growth, and degradation of coating materials and to explore possible pathways to mitigate or eliminate the corrosion. In this combined method, LIBS will be used to identify whether and what elements in coatings are attacked by fungi. MS will be used to identify the forms of elements attacked in the fungal biofilms, determine the fungal metabolic products, and understand the product formation pathways. Raman spectroscopic techniques, including spontaneous and coherent anti-Stokes Raman spectroscopy (CARS), will be used to visualize the chemical composition changes and monitor the formation of fungal biofilms to achieve a complete understanding of the coating degradation caused by fungal biofilms.
The proposed research will lead to a new fundamental understanding of the biocorrosion processes induced by fungi in nonresistant coating materials, as needed to meet Department of Defense (DoD) requirements. A thorough understanding of the degradation mechanisms will provide possible pathways to suppress or avoid biocorrosion. Therefore, the research project will significantly impact multiple facets of scientific understanding and technological applications as related to biocorrosion in nonresistant coating materials.