Kinetic Monte Carlo simulation of the adsorption competition of epoxide components
J. Kundin, J. M. Knaup, T. Frauenheim, H. Emmerich.
Soft Materials, 10, 235-256, (2011)
In the present work we describe a kinetic Monte-Carlo method (KMC) in the framework of the lattice gas model for the simulation of the adsorption in multicomponent systems from a liquid solution. The algorithm is subsequently used for an investigation of the influence of an adhesion promoter additive on the adsorption of amine-curing epoxide components on the aluminium oxide surface. The KMC method is coupled to the Metropolis algorithms to accelerate the simulations and take into account effects of various adsorption sites and neighboring adsorbates. An inclusion of the bulk diffusion in the simulation scheme allows to study the distribution of components in the solution near the interface. Parameters used in the simulations are reaction barriers and reaction energies for the surface complex formation. They were calculated in previous works by using density functional based tight binding (1–3 Knaup, J. M., Köhler, C., Frauenheim, T., Blumenau, A. T., Amkreutz, M., Schiffels, P., Schneider, B. and Hennemann, O.-D. 2006. Computational Studies on Polymer Adhesion at the Surface of γ-Al2O3. I. The Adsorption of Adhesive Component Molecules from the Gas Phase. J. Phys. Chem. B, 110: 20460–20468. Knaup, J. M. 2008. Ph.D. thesis, Paderborn, , Germany: Universität Paderborn. Knaup, J. M., Tölle, P., Köhler, C. and Frauenheim, T. 2009. Quantum Mechanical Simulation Approaches Bridging Length and Time Scales for Simulation of Interface Reactions in Realistic Environments. Eur. Phys. J. St, 177(1): 1951–6355. ). Results of the simulations show that the small additions of the adhesion promoter (˜2%), which adsorption is more favourable in comparison to other components, lead to the essential increasing of surface concentration of adsorbed molecules and as a consequence to the increasing of the adhesive strength. The analysis of simulated adsorption kinetics allows us to evaluate the engineering rules, which can be useful in the optimisation of the adhesive technology.