Force Field Parameterization and Molecular Dynamics Simulation of Epoxy Interaction with Boron Nitride Nanotube Surfaces

Abstract

Wettability is a key phenomenon in understanding solid-liquid interface behavior in composite materials and is important in the manufacturing of boron nitride nanotube (BNNT)-based composite materials. Wettability is often quantified by calculating the contact angle values of liquid resin droplets on reinforcement surfaces. Determining contact angle values using experimental techniques for nanomaterials like BNNT is challenging and costly. Computational simulations with interface calculation capabilities offer an easier approach to solve this problem. In this study, a molecular dynamics framework is used to determine the contact angle values of various epoxy systems on the BNNT surface. The Interface Force-Field (IFF) was used for this study. Forcefield parameters were developed to describe the interaction of boron (B) atoms, nitrogen (N) atoms, and the pi electrons that dominate the out-of-plane behavior of two-dimensional B-N materials. A single layer BNNT surface was modelled as shown in “Figure 1â€. For wetting simulations, the selection of resin system is based on a combination of EPON 862 and EPON 828 monomers with aromatic amine hardeners and aliphatic amine hardeners. The results are dependent on the chemical groups present in the resin system, temperature, and the charges on the atoms in the functional groups. The EPON 828 systems show overall better wettability than EPON 862 systems irrespective of choice of hardener.