Method development: Iterative QM/MD approach to generate molecule-surface potentials
In the framework of modeling polymer coating systems on solid substrates we are currently working on a software package to automate the generation of molecule-surface potentials. This is done in an iterative QM/MD approach that allows us starting from a DFT minimum energy structure (and the corresponding adsorption energy) to develop classical force field potentials to describe the interaction between the molecules and surfaces (metal or metal oxide surfaces). The corresponding iterative scheme that is used is shown in the picture.
For organic coatings polymers like polyurethanes are used as typical materials. It is computationally not feasible to calculate the adsorbed state of the long polymer chains with ab intio methods. That is why we make use of the so called building block approach, where smaller fragments of the polymer (“building blocks”) are used to derive force field potentials (shown in the picture: ethanol on alumina).
P. Schravendijk, L. M. Ghiringhelli, L. Delle Site, N. F. A. van der Vegt, J. Phys. Chem. C, 111, 2631-2642 (2007).