基于单宁酸负载的自预警-自修复双重功能防腐涂层

Self-Reporting and Self-Healing Dual Functional Anticorrosive Coating based on Tannic Acid Additives

通过一步合成法制备了负载单宁酸(TA)的显色、缓蚀双功能介孔二氧化硅纳米填料(TA-MSNs),将其掺杂到环氧涂层中,探究涂层的自预警和自修复性能。首先对TA的显色性能及缓蚀性能进行了表征,接着对TA-MSNs纳米填料的形貌结构以及TA的释放行为规律进行了探究,并综合分析纳米填料添加量对涂层自预警及自修复性能的影响规律。盐雾实验结果表明,涂层的自预警效果与填料含量呈正相关,5%(w)以上的TA-MSNs添加量可赋予涂层明显的显色性能。电化学阻抗谱和表面分析结果表明,TA-MSNs在涂层中的含量为5%时,破损涂层的低频阻抗模值比纯环氧破损涂层高出2个数量级。当涂层破损时,涂层中释放的TA分子能够与钢铁腐蚀形成的Fe^(3+)发生络合,产生蓝黑色预警金属腐蚀,同时络合物可形成金属表面保护膜层,抑制了腐蚀反应的进一步发展。综上,添加5%TA-MSNs的环氧涂层具有优异的自预警和自修复效果。

Tannic acid molecules are loaded into mesoporous silica nanoparticles(TA-MSNs) by one-step synthesis method to endow them with corrosion sensing and corrosion inhibition dual functions.TA-MSNs are added into the epoxy coatings to explore the self-reporting and self-healing performances of composite coatings.Firstly,the coloration and corrosion inhibition properties of TA are characterized.Then,the morphology and structure of TA-MSNs are investigated,and the release behaviors of TA from TA-MSNs studied.The influence of nanofiller content on the self-reporting and self-healing performances of coatings is comprehensively analyzed.Salt spray test indicates that the self-reporting effect of the coating is positively correlated with the filler content,and the addition of more than 5%(w) TA-MSNs could give the coating obvious coloration effect.Electrochemical measurement and surface analysis show that the low-frequency impedance modulus(|Z|_(0.01 Hz)) of the damaged coating with 5% TA-MSNs is two orders of magnitude higher than that of the damaged blank epoxy coating.When the coating is damaged,TA molecules released in the coating can be complexed with Fe^(3+) formed during steel corrosion,resulting in blue-black coloration for corrosion reporting,and the complex adsorbed on the metal surface can form a protective film layer to inhibit further corrosion reaction.In summary,the epoxy coating with 5% TA-MSNs possesses excellent self-reporting and self-healing performance.