海藻酸及白蛋白在铝基涂层表面贴附机制及其对污损生物膜和涂层耐蚀性能的影响研究

Biofouling is a major concern for maritime structures and affects markedly the performances of thermal sprayed anti-corrosive coatings. As the first stage participating in the biofouling process, adsorption of the molecules (conditioning layer) plays key roles in mediating formation of biofilm and following development of biofouling. This project utilizes thermal sprayed aluminum-based coatings for investigating the adsorption behaviors of alginate and albumin, the typical polysaccharide and protein, and subsequent colonization of E. coli and biatoms. Dynamic adsorption behaviors of alginate/albumin are to be investigated and their conformational changes upon adsorption on the coatings are to be analyzed at molecular level by reconstructing their three-dimensional (3D) structures by single particle electron microscopy technique. Further influence of the molecules on colonization of E. coli and diatoms and their relations with biocorrosion of the aluminum-based coatings are also investigated. Through the interpretation of the 3D structures of the molecules and understanding of the relations among conditioning layer, biofilm, and biocorrosion, this research is aimed to provide fundamental insights into selection of cost-efficient and environment-friendly marine coating materials, design of coating structures, and regulation of biofouling processes.

生物污损显著影响热喷涂海洋耐蚀涂层的服役性能，而有机大分子（如多糖/蛋白质）条件膜的形成是海洋生物污损发生和发展的首要环节，继而结合材料表面特性调控和决定后续系列生物污损行为。本项目利用热喷涂铝基涂层为典型海洋无机耐蚀材料体系，选择海藻酸和白蛋白为典型多糖/蛋白，结合单颗粒电镜技术等手段，从分子水平研究海藻酸/白蛋白在材料表面贴附行为，探讨条件膜与大肠杆菌/硅藻定殖（生物膜）行为的关系，并研究条件膜与生物膜对涂层腐蚀行为的影响。基于上述研究，建立利用单颗粒电镜技术重构海洋材料表面贴附多糖/蛋白构象的实验方法，揭示影响海藻酸和白蛋白贴附及其结构变化的耐蚀无机材料涂层关键表面特征参数，明确海藻酸和白蛋白的贴附行为对大肠杆菌/硅藻的定殖等行为的影响机制，并揭示条件膜/生物膜对铝基涂层耐腐蚀性能的影响规律，为热喷涂海洋涂层材料选择、涂层表面结构设计以及生物污损调控提供基础实验数据。

针对海洋生物污损发生机理和演变规律，本项目以热喷涂铝基海洋涂层为典型材料体系，系统制备和表征了耐蚀铝基涂层，选择海藻酸和白蛋白为典型条件膜成分，大肠杆菌、芽孢杆菌、小球藻、三角褐指藻等为典型细菌/硅藻，深入研究了污损条件膜及生物膜的形成机制和调控机理；通过采用单颗粒电镜技术，重构了贴附于涂层表面的海藻酸和白蛋白二维及三维空间结构，并从分子水平明确了海水中典型金属阳离子对条件膜形成和发展的影响机制；同时利用生化技术方法揭示了快速形成的条件膜及其特性对涂层电化学性能的影响规律，并较系统地研究了条件膜对涂层耐蚀性能的影响机理和调控机制。基于本项目研究成果，利用热喷涂等技术构筑了数种环保耐蚀防污涂层体系。本研究创新性地把单颗粒电镜技术（冷冻电镜技术）用于海洋材料表面贴附多糖/蛋白结构的研究，并结合耐蚀铝基无机涂层表面化学和结构的调控制备，阐明了材料表面典型化学特性和微纳米结构特征对生物污损条件膜形成的影响机制。本项目成果为开展海洋污损基础研究和开发环保高效防污耐蚀涂层技术提供了新的思路和基础数据。