Enhanced corrosion protection property of Li-Al layered double hydroxides (LDHs) film modified by 2-guanidinosuccinic acid with excellent self-repairing and self-antibacterial properties.

Abstract The long-lasting chrome-free, corrosion-resistant surface treatment of aluminum is of crucial importance. In our work, we prepared an intrinsic self-repairing and self-antibacterial film of single step in-situ grown inorganic lithium (Li), aluminum (Al)-containing layered double hydroxides film modified by 2-guanidinosuccinic acid (denoted as GLDHs) on the surface of 6 N01-T5 Al alloy by a facile method with enhanced corrosion protection performance. A series of electrochemical tests and neutral salt tests (NSS) showed that the corrosion resistance performance of GLDHs was significantly improved as compared with blank LiAl-LDH film. Interestingly, an artificial defect in the GLDHs film exhibited remarkable performances of self-repairing. After immersion in 3.5 wt% NaCl solution for certain time, new LiAl-LDH film at the Al alloy surface were formed, which was characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), inductive coupled plasma emission spectrometer (ICP), elemental analyzer, polarization curves, electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). A self-repairing mechanism was proposed and discussed. Furthermore, GLDHs also exhibited excellent self-antibacterial activity toward Escherichia coli and Bacillus subtilis. The high self-antibacterial performance of GLDHs film could attribute to the modified 2-guanidinosuccinic acid. Our full demonstration of the multifunctional GLDHs film is considerably beneficial to the researchers to further understand its potential for the practical application in the field of corrosion protection of aluminum and aluminum alloy. Highlights • Li-Al layered double hydroxides (LDHs) film on aluminum alloy. • Multifunctional conversion film with enhanced corrosion protection property. • Excellent self-repairing property and the possible mechanism. • Excellent self-antibacterial property and the possible mechanism. [ABSTRACT FROM AUTHOR]