Abstract:

Monolayer films of 2-amino-5-mercapto-1,3,4-thiadiazole-4-hydroxy benzaldehyde (A) and 2-aminobenzimidazole-4-hydroxy benzaldehyde (B) were fabricated respectively on copper surface by molecular self-assembled process. The corrosion inhibition performance of the Schiff self-assembled films (SAMs) in 3% NaCl solution was examined by electrochemical methods. The results indicated that SAMs could effectively inhibit the corrosion on the copper. The best corrosion inhibition rate of Schiff base A reached to 98.9% with the concentration of 15 mmol·L^-1 and assembly time of 6 h at 25℃. The best corrosion inhibition rate of Schiff base B reached to 96.73% with the concentration of 20 mmol·L^-1 and assembly time of 12 h at 25℃. The surface analysis showed that a protective film on the surface of copper was formed, which effectively blocked the transfer of corrosive medium to the metal substrate. Quantitative calculation and molecular dynamics simulation were used to analyze the relationships between the molecular structure and corrosion inhibition performance of two inhibitors of A and B, and the adsorption form on copper surface. The results showed that two inhibitors had good corrosion inhibition performance. The inhibition effect of A was better than that of B, which was consistent with the experimental results.

Key words: Schiff base, self-assembled membrane, corrosion inhibition, quantum chemistry, dynamic simulation

摘要：

通过分子自组装技术在铜表面制备2-氨基-5-巯基-1，3，4-噻二唑缩对羟基苯甲醛（简称A）和2-氨基苯并咪唑缩对羟基苯甲醛（简称B）缓蚀膜。采用电化学测试方法研究了两种席夫碱自组装膜在质量分数为3%的NaCl溶液中对铜的缓蚀作用。结果表明，自组装分子膜能有效抑制铜片的腐蚀，对于席夫碱A，当溶液浓度为15 mmol·L^-1，组装时间为6 h时缓蚀效果最佳；对于席夫碱B，当溶液浓度为20 mmol·L^-1，组装时间为12 h时缓蚀效果最佳，A、B的缓蚀效率分别达到98.9%和96.73%。表面分析技术表明，席夫碱化合物在铜表面形成一层保护膜，有效阻挡了腐蚀粒子向金属基底的转移，从而抑制了腐蚀的发生。量化计算和分子动力学模拟分析了A、B两种缓蚀剂分子构型与缓蚀性能的关系以及在铜表面的吸附形态，结果表明，两种缓蚀剂具有很好的缓蚀性能，且缓蚀效果A>B，与实验结果一致。

关键词: 席夫碱, 自组装膜, 缓蚀性能, 量子化学, 动力学模拟