CAREER: Corrosion Resistance of Nano-meter Graphene Coatings in Aggressive Microbial Environment

CBET -1454102 GadhamshettyCAREER：纳米石墨烯涂层在侵蚀性微生物环境中的耐腐蚀性据报道，在美国，金属腐蚀对基础设施的直接和间接影响的年度成本接近1万亿美元。微生物腐蚀占总腐蚀费用的近20- 40%。虽然有几种保护涂层可用于金属保护，但商业涂层往往在水性和微生物环境中失效。该项目的中心目标是研究一种新型的微创（厚度为几纳米），无针孔，坚固耐用的保护涂层，由保形石墨烯制成，用于防止微生物腐蚀。这个CAREER项目能够合理设计下一代微创，纳米级，耐微生物腐蚀的涂层，其特征是石墨烯构建块。它将专注于四个更广泛的影响目标：1）开发一个基于IBM的虚拟实验室，为学生提供微生物腐蚀/Gr实验的实践教程; 2）将石墨烯研究纳入本科课程; 3）鼓励代表性不足的美国印第安人（从9个SD保留）加入BS和MS学位;与教育专家合作，评估教育/这个CAREER提案旨在为我们理解石墨烯在微生物条件下有效工作的原因做出根本性的贡献。为此，PI将使用脱硫弧菌作为硫酸盐还原菌的模型，以研究石墨烯涂层在与以下因素相关的不同刺激下的有效性：i）电化学约束，ii）生理参数，iii）石墨烯中的点缺陷，iv）石墨烯的润湿性，v）石墨烯的细胞毒性，以及vi）石墨烯生产技术。在初步研究中，详细的电化学分析显示，与Parylene涂层相比，石墨烯的抗微生物腐蚀性提高了约100倍，与裸石墨烯相比提高了约41倍，与聚氨酯涂层相比提高了约10倍。这些发现显示了耐微生物腐蚀的石墨烯涂层的前景，因为它们的平均厚度（1-2 nm）比Parylene（40-50 nm）小25倍，比聚氨酯（20-80微米）小4000倍。显微镜和光谱技术揭示了在本研究中观察到的微生物（例如，γ变形菌内的链养单胞菌属物种）可以攻击聚合物并诱导微米长度的撕裂，导致非保形聚合物涂层，而石墨烯涂层被发现是电化学惰性的，非常保形的，并且抵抗微生物攻击。纳米级石墨烯涂层也对底层表面拓扑结构造成最小的变化。

CBET - 1454102GadhamshettyCAREER: Corrosion Resistance of Nano-meter Graphene Coatings in Aggressive Microbial EnvironmentThe annual costs for the direct and indirect effects of metallic corrosion on infrastructure have been reported to reach nearly $1 trillion in United States. Microbial corrosion accounts for nearly 20-40 % of the total corrosion costs. While there are several protective coatings available for metal protection, the commercial coatings tend to fail in the aqueous and microbial environments. The central goal of this project is to investigate a new class of minimally invasive (thickness of few nanometers), pin-hole-free, robust, and protective coatings made from conformal graphene for use against microbial corrosion. This CAREER project enables the rational design of the next generation of minimally invasive, nanometer-scale, microbial-corrosion resistant coatings featuring graphene building blocks. It will focus on four broader impact objectives: 1) to develop an Adobe-director-based virtual laboratory to provide students with hands-on tutorials on microbial corrosion/Gr experiments; 2) to integrate graphene research in undergraduate curriculum; 3) to encourage under-represented American Indians (from 9 SD reservations) to join BS and MS degrees; and 4) to work with educational experts to evaluate the educational/outreach activities.This CAREER proposal seeks to make fundamental contributions in our understanding on why graphene works effectively under microbial conditions. Towards this end, the PI will use Desulfovibrio vulgaris as a model for sulfate-reducing bacteria to investigate the effectiveness of graphene-coatings under varying stimuli related to: i) electrochemical constraints, ii) physiological parameters, iii) the point defects in graphene, iv) wettability of graphene, v) cytotoxicity of graphene, and, vi) graphene-production techniques. In preliminary studies, a detailed electrochemical analysis revealed that the graphene offers ~100-fold improvement in microbial corrosion resistance compared to Parylene coatings, ~41-fold compared to bare graphene, and ~10-fold compared to polyurethane coatings. These findings shows a promise for microbial corrosion-resistant graphene coatings as their average thickness (1-2 nm) is 25-fold smaller than Parylene (40-50 nm), and 4000-fold smaller than polyurethane (20-80 micron). The microscopy and spectroscopy techniques revealed that the microbes observed in this study (e.g. Strenotrophomonas species within gammaproteobacteria) can attack polymers and induce micron-length tears leading to non-conformal polymer coatings, while the graphene coating was found to be electrochemically inert, extremely conformal, and resistant to microbial attack. The nano-scale graphene coatings also cause minimal changes to the underlying surface topology.