The effect of interlayer spacing on the inhibitor release capability of layered double hydroxide based nanocontainers

Layered double hydroxide (LDH) nanoparticles are utilized as nanocontainers for reserving corrosion inhibitors in order to construct a controlled release system with targeted delivery of inhibitive compounds on the corrosion sites of metal. In this way, the NO intercalated Zn-Al LDH nanoparticles were synthesized through the co-precipitation route with different interlayer spacing by changing the pH of synthesis. The structure and interlayer spacing were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy, Field emission scanning electron microscopy and high-resolution transmission electron microscopy. The outcomes showed that the greatest interlayer spacing belonged to the LDH particles synthesized at pH = 9.5 +/- 0.5. The relation between the interlayer spacing and inhibitor release performance is discussed and conceptualized for the first time in this study. Results revealed that the structure and interlayer spacing strongly depends on the pH of the synthesis process. It was found that the synthesis pH is the most influential parameter affecting the inhibitor release by changing the interlayer spacing and ion charge density. Moreover, the LDH synthesized at pH = 9.5 +/- 0.5 with a higher interlayer spacing exhibited the best corrosion inhibition performance. The results from surface characterizations also confirmed the formation of a protective film over the mild steel surface. The obtained material is believed has great potential being an environmentally friendly nanocontainer or nanopigment. It is thus recommended that the obtained material can be utilized to inhibit the metals from corrosion and provide ion-exchange via harsh ions of saline solution at the onset of corrosion. (C) 2019 Elsevier Ltd. All rights reserved.