Study of Metal/Epoxy Interfaces between Epoxy Precursors and Metal Surfaces Using a Newly Developed Reactive Force Field for Alumina–Amine Adhesion

Abstract

In this work we study the adhesion between various alumina surfaces and precursors of amine-containing epoxies.To accomplish this we have developed a reactive force field (ReaxFF) parameterization for the aluminum-nitrogen interaction and combined this with the aluminum-water and glycine force fields reported in earlier work. Molecular clusters and reaction paths selected to model interfacial phenomena of amine-containing epoxy precursors on alumina were used in the fitting of the ReaxFF parameters. It is shown how this new force field satisfactorily reproduces equilibrium bond lengths and angles as well as binding energies for the proposed structures. Reaction profiles are also fitted in agreement with ab initio calculations performed making use of the nudge elastic band method. To substantiate the parametrization, room temperature molecular dynamics results of ammonia adsorption on alumina are compared using ab initio and ReaxFF methods. Using this new interaction scheme, adsorption energies of dimethylamine and DETA on differently terminated alumina surfaces are determined for ten different molecule-surface approach conditions each. We find that the mean and rms adsorption energy values vary considerably with the particular molecule/surface combination. It is also shown that the adhesion of the studied epoxy precursors decreases linearly with the hydroxyl coverage on alumina surfaces.

Thermodynamic Simulation of the RDX–Aluminum Interface Using ReaxFF Molecular Dynamics

“…We have produced a new ReaxFF reactive force field for aluminum and RDX interactions, based on previously published parameters for Al 33,[47][48][49] , C, H, N and O…”

“…All simulations were performed using the LAMMPS package in the framework of potential functions described by the ReaxFF force field. , The ReaxFF parametrization for C/H/N/O/Al is composed of original C/H/N/O parameters and modified Al parameters. ,− The C/H/N/O parameters used here are fully transferable to the “combustion” ReaxFF set described by Chenoweth et al The training data captures dissociation pathways and energies for a number of nitramine materials. Several prior publications ,− have proved ReaxFF’s accuracy to describe thermo-chemistry or mechanical-chemistry coupling in nitramines.…”

Adsorption of Epoxy Oligomers on Iron Oxide Surfaces: The Importance of Surface Treatment and the Role of Entropy

“…There have been several papers published looking at the interaction of DGEBA and related epoxy systems on alumina, including Semoto et al, 13 Knaup et al, 14 Yoshizawa et al, 15 and Kruger et al, 16 who all employ quantum mechanical approaches to investigate the bonding contributions. Valega Mackenzie et al 17 have developed a reactive force field approach to model alumina−amine interactions to capture the bond formation between the surface and the adsorbate. Lee et al 18 investigated the bonding of DGEBA on an iron (100) surface, and unlike on an alumina surface, no chemical bonds were found to form between DGEBA and the iron surface.…”

The Bonding Mechanism of the Micro-Interface of Polymer Coated Steel

“…The adhesion and mutual bonding of polymer materials on metal surfaces is an important research direction in the field of surface science [ 14 , 15 , 16 ].At present, there are four main types of metal and non-metal adhesion mechanisms generally recognized in the world: mechanical interlocking theory, electronic theory, diffusion theory, and adsorption theory [ 17 ].…”