高等学校化学学报 ›› 2019, Vol. 40 ›› Issue (1): 96-107.doi: 10.7503/cjcu20180589

• 物理化学 • 上一篇    下一篇

十八胺基分子组装体在碳钢表面的作用机理与模拟

马玉聪1, 樊保民1(), 郝华2, 吕金玉1, 冯云皓3, 杨彪1   

  1. 1. 北京工商大学材料与机械工程学院, 北京 100048
    2. 中国科学院化学研究所, 北京 100190
    3. 北京化工大学材料科学与工程学院, 北京 100029
  • 收稿日期:2018-08-23 出版日期:2019-01-10 发布日期:2018-12-20
  • 作者简介:

    联系人简介: 樊保民, 男, 博士, 副教授, 主要从事超分子化学与腐蚀电化学方面的研究. E-mail: fanbaomin@btbu.edu.cn

  • 基金资助:
    国家自然科学基金(批准号: 21606005, 51473007)和北京市教委科研计划一般项目(批准号: SQKM201710011001)资助.

Experimental and Theoretical Studies of Action Mechanism of an Octadecylamine-based Molecular Assembly on Mild Steel

MA Yucong1, FAN Baomin1,*(), HAO Hua2, LÜ Jinyu1, FENG Yunhao3, YANG Biao1   

  1. 1. School of Materials and Mechanical Engineering, Beijing Technology and Business University, Beijing 100048, China
    2. Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
    3. Department of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
  • Received:2018-08-23 Online:2019-01-10 Published:2018-12-20
  • Contact: FAN Baomin E-mail:fanbaomin@btbu.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos.21606005, 51473007) and the Science and Technology Development Project of Beijing Municipal Commission of Education, China(No.SQKM201710011001).

摘要:

应用分子动力学模拟明确了以β-环糊精(β-CyD)为主体、 十八胺(ODA)为客体的分子组装体(CDDA)的最优空间构型, 并采用动态失重、 电化学极化与阻抗测试结合扫描电子显微镜、 原子力显微镜、 接触角、 X射线光电子能谱(XPS)与衰减全反射红外光谱(ATR-FTIR)等表面分析手段, 研究了CDDA对Q235碳钢在蒸汽凝结水中的缓蚀机理. 结果显示, CDDA的4种构型可共存于组装体系内; 35 ℃下, 添加1 mmol/L CDDA对碳钢的缓蚀率达94.1%; 添加CDDA不改变腐蚀机理, 但可同时抑制电化学反应的阴、 阳极过程, 并显著提升极化阻抗, 属于阳极抑制为主的混合型缓蚀剂. XPS和ATR-FTIR结果均表明, CDDA在碳钢/溶液界面释放客体ODA, 并由其自发吸附组装形成疏水膜, 吸附过程符合Langmuir等温式. 分子动力学模拟与量子化学计算结果支持上述ODA释放并于金属表面组装成膜的推断.

关键词: 蒸汽凝结水, 十八胺, 分子识别与自组装, 分子动力学, 量子化学

Abstract:

A supramolecular complex CDDA was prepared based on β-cyclodextrin(β-CyD) and octadecylamine(ODA). Four possible configurations of CDDA might coexist in the supramolecular system based on molecular dynamics simulation(MD). The corrosion inhibition effect and mechanism of CDDA for Q235 steel in the condensate water was evaluated via dynamic weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy(EIS), coupling with scanning electron microscopy(SEM), atomic force microscopy, contact angles, X-ray photoelectron spectroscopy(XPS) and attenuated total reflection infrared spectroscopy(ATR-FTIR). The inhibition efficiency for mild steel in the condensate water could reach 94.1% with 1 mmol/L CDDA at 35 ℃. The corrosion mechanism of mild steel in the condensate water was not altered in the presence of CDDA; however, both the anodic and cathodic processes were inhibited along with the elevated polarization resistance. CDDA could be treated as a mixed-type inhibitor with predominantly anodic dominant. The results of XPS and ATR-FTIR indicated that ODA could be released from CDDA at on the metal/solution interface and form a protective monolayer film. The adsorption process could be well fitted by the Langmuir adsorption isotherm. Molecular dynamics simulations provided the visual evidence of the assembly mechanism of CDDA on the mild steel surface. The release of ODA from CDDA and assembly mechanism on the steel/solution interface were verified by MD and quantum chemical calculations based on density functional theory.

Key words: Condensate water, Octadecylamine, Molecular recognition and self-assembly, Molecular dynamics, Quantum chemistry

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