Interface engineering of LDH-based material as efficient anti-corrosive system via synergetic performance of host, interlayers, and morphological features of nature-mimic architectures

Abstract

High-performance hybrid materials with special features are desired to meet the requirements of more complex cutting-edge applications. However, the self-assembly of layered double hydroxides (LDH) with organic frameworks is hampered by a lack of understanding of the formation mechanism and the effects of the self-assembled architecture on anticorrosion activity remain a major challenge. Herein, we put forward how the honeycomb-like network would architecturally upgraded on the pre-existing hierarchical floral structure with Trimesic acid (TMA) compound resulting in a promising layer-by-layer (LBL) material. This nature-inspired network is realized to offer an ideal approach not only endows with excellent properties but also exploits the power of layered coating materials as a bastion in the fields of nanotechnology, without limiting conditions, taking advantage of the synergy beneficial effects of the self-assembled honeycomb-like TMA and the anion-exchange ability of the layered coating material. In this work, a three-dimensional assembly with an architecture closely resembling interconnected micro-petals was successfully deposited on the defective surface obtained via plasma electrolytic oxidation (PEO) of Mg alloy, where TMA compound was used for supramolecular self-assembly. The MgO layer was first formed on AZ31Mg alloy via PEO treatment and the Mg-Al LDH micro-petals were synthesized on the MgO surface in the presence of a chelating agent [diethylenetriaminepentaacetic acid (DTPA)]. In a typical synthesis, TMA compound was used as an appropriate linker for the formation of well-organized multidimensional layered materials taking advantage of the synergy beneficial effects of the self-assembled honeycomb-like TMA and the anion-exchange ability of the Mg-Al LDH coating. The results indicate that Mg alloy coated with the self-assembled TMA@LDH-MgO materials presents excellent anti-corrosion performance as compared to the bare Mg. The use of such system would open a brand-new possibility to correct, in a targeted way, the inevitable defects of the layered coating morphology while retaining its exceptional potential. First-principles calculations, quantitative molecular surface analyses and independent gradient model framework further verify the self-assembly and adsorption behavior of TMA over the Mg-Al LDH layer. The improved performance of the TMA@Mg-Al LDH film is attributed to the synergistic effects of different interactions that occurred around active sites in the hierarchical network.