Molecular dynamic investigations of aluminum nanoparticles coated by the mixtures of ethanol and diethyl ether with different molecular proportions

Aluminum nanoparticles (ANPs) are considered energetic, economical, and eco-friendly additives. In this investigation, advanced ReaxFF molecular dynamics (MD) simulation has been used to discover the mechanism of coating ether and ethanol molecules on ANPs. Those MD results generally reveal the dynamics process of ethanol and ether adsorption. It is found that the adsorption of ethanol and ether molecules is not a physical adsorption process only. Newly generated aluminum-oxygen bonds are formed between oxygen atoms and aluminum atoms. Those oxygen atoms come from both ethanol and ether molecules. Moreover, ethanol and ether molecules generate ethyl and new ethanol molecules during the adsorption process. The radial distribution function curves and adsorption curves are used to describe the adsorption process. The results show that the adsorption amount of ethanol molecule is significantly higher than that of the ether molecule. It is observed that the outermost aluminum atoms form an organic-provided alumina layer, the inside of ANPs is active aluminum atoms, and the outside is the organic coating layer. Heating could eliminate the hydrogen-bonding between solution molecules. High pressure and high temperature destroy the external structure of aluminum particles, which makes atoms migrate to the interior of aluminum particles. Finally, the oxidation resistance test shows that at 300 K, the organic coating layer can maintain good stability and oxidation resistance.