Structural evolution of APh-LDH-MgO layers with nature-mimic architecture
M.CHAFIQ- A.CHAOUIKI- Y.G.KO

Materials Electrochemistry Group, School of Materials Science and engeneering, yeungnam university Gyongsan 38541, republic of korea

Abstract

Layered double hydroxides (LDH)-based materials are drawing
considerable attention over the years in many fields. The controlled and
flexible composition of the layers, as well as the wide range of possible
anionic guests and easy adaptability for versatile applications, are some of
many reasons for their wide usability. However, current LDH synthesis is
usually in situ grown in autoclave under high temperature and high-
pressure conditions. In this work, the possibility of direct synthesis of LDH
on plasma electrolytic oxidation (PEO) treated magnesium alloy in the
presence of a chelating agent (diethylenetriaminepentaacetic acid - DTPA)
is reported to avoid hydrothermal autoclave conditions, which strongly
limit wide industrial application of such coating systems. Herein, by
optimizing the pH and duration of the LDH reaction, a three-dimensional
assembly has been reported with architecture closely resembling
interconnected nano &quot-petals&quot- producing 3D rosette-like structures. This
LDH system was compared with the process in which an organic layer was
fabricated on the top of LDH film using aminophenol (APh) compound in
order to construct a hybrid architecture consisting of organic-inorganic
self-assembly. This strategy results in a smart hierarchical structure which
can provide robust LDH-APh film with superb anticorrosion performance.
At the molecular level, the first-principles DFT calculations were used to
provide theoretical understanding of the interfacial mechanism and
elucidate the mutual interactions in LDH system.

Keywords: Magnesium alloy, Layered double hydroxide, Plasma electrolysis, Chelation, rosette-like morphology.

Topic: Industrial and Engineering Chemistry