具有聚集诱导发光效应的缓蚀剂的设计合成及其吸附与荧光特性研究

Metal corrosion happens ubiquitously in all walks, causing severe detriments to metallic materials and installations. Addition of corrosion inhibitors is a common and effective strategy to resist corrosion. Imidazoline, as well as its derivatives, and carboxylic compounds are frequently-used corrosion inhibitors. Whereas there are still some shortcomings in their applications. Reports rarely lie in the intactness of the adsorption film formed by the corrosion inhibitors on metal surface. The concentration of the corrosion inhibitor is hard to determine in corrosive medium. Besides, the mechanism of anticorrosion is not quite clear in some cases. Based on the aggregation-induced emission (AIE) effect of tetraphenylethylene (TPE), as well as its features of high electron density and big hydrophobic framework, new kinds of water-soluble or water-dispersive cationic and non-ionic TPE-based corrosion inhibitors will be developed. When dissolved or dispersed in corrosive medium, such TPE-based corrosion inhibitors do not emit fluorescence. Once got adsorbed onto the metal surface, they show intensive fluorescence. Hence, exploration of the fluorescent characteristics of the metal surface is helpful to study the adsorption process and the intactness of the adsorption film. Moreover, the anticorrosion and adsorption mechanism will be disclosed by the favor of computational calculation. In addition, the concentration of the TPE-based corrosion inhibitors can be confirmed by UV-Vis and FL analysis. Through above efforts, the types of corrosion inhibitors will be enriched. And the dosing and control systems will also be improved, leading to reduction of metal corrosion, especially some more devastating localized corrosion. This project may also contribute to solidify the safety and long period operation of industrial metallic facilities.

金属材料的腐蚀现象普遍且危害严重，添加缓蚀剂是一种有效的防腐蚀方法。常用的咪唑啉类、羧酸类缓蚀剂等具有较好的缓蚀效果，但存在一些不足，在金属表面形成吸附膜的完整性鲜见报道，在介质中的浓度难以测定，缓蚀作用机理亦不十分明确。为了解决这些问题，本项目利用四苯乙烯的聚集诱导发光（AIE）效应及其富电子、疏水基大的结构特点，设计合成水溶性或水分散性阳离子型和非离子型四苯乙烯基缓蚀剂。当这些缓蚀剂分子溶解或分散在腐蚀性介质中时，不发射荧光或荧光很弱，而在金属表面发生吸附后荧光显著增强。通过分析金属表面的荧光特性，探究缓蚀剂分子在金属表面的吸附过程及吸附的完整性；结合理论化学计算，揭示吸附过程和缓蚀作用机理；以紫外和荧光分析，测定缓蚀剂分子在介质中的浓度。本项目可丰富缓蚀剂的种类，指导优化缓蚀剂的加药和控制条件，抑制金属腐蚀，尤其是危害严重的局部腐蚀，为保障工业设备的安全和长周期运行做出贡献。

金属腐蚀现象无处不在，危害严重，添加缓蚀剂是一种常用的防护方式。本项目基于四苯乙烯的聚集诱导发光效应、富电子、疏水性和空间位阻大等特点，设计合成了多种新结构的阳离子型和非离子型四苯乙烯缓蚀剂，以核磁共振氢谱、核磁共振碳谱、高分辨质谱等对分子结构进行了表征。通过紫外-可见吸收光谱，建立了检测浓度的方法。确认了它们的聚集诱导发光性质。以腐蚀失重试验，验证它们在腐蚀介质中对两种最常用的金属——黄铜和碳钢，均具有高效的缓蚀性能，对黄铜缓蚀率最高超过99%，对碳钢缓蚀率最高超过98%。在黄铜或碳钢表面的吸附均符合Langmuir吸附等温式，根据吸附-脱附平衡常数和吉布斯自由能的计算结果，确认在黄铜或碳钢表面的吸附均为热力学自发过程，且为强作用的化学吸附。XPS分析金属表面元素组成，证明了缓蚀剂分子在金属表面形成了保护性吸附膜，并以SEM、接触角测试等表征了金属表面状态。对于吸附有四苯乙烯缓蚀剂的黄铜和碳钢试片，经365 nm紫外光激发，黄铜表面发射明显荧光、保留了AIE效应，碳钢表面未发射荧光、即淬灭了荧光。以软硬酸碱理论、密度泛函理论、分子动力学、巨正则蒙特卡洛等研究了吸附和缓蚀作用机理。基于研发的四苯乙烯缓蚀剂的高效缓蚀性，及其在黄铜表面的吸附和荧光行为，可为金属缓蚀提供荧光可视化的新方法，在强荧光处不需补加药剂，只需在弱/无荧光处定向补加药剂，以替代当前工业上普遍采用的每天或每周期定量加药的方式，如此可有效节约药剂、提高药剂使用效率。