On the interactions between poly(ethylene oxide) and graphite oxide: a comparative study by different computational methods.

The aim of this work is to investigate polymer[middle dot][middle dot][middle dot]substrate interactions for a polymer nanocomposite material: poly(ethylene oxide) (PEO) confined in graphite oxide (GO). Six discrete and simplified models (one for PEO and five for GO) have been chosen in order to reproduce the most likely PEO···GO interactions. Twelve potential interaction energy curves have been built using the models and curve minima have been optimized using the 2nd order Møller-Plesset perturbation theory (MP2)∕6-31+G(d) method. The intermolecular interactions have been analyzed in terms of distances, stabilities, and bond critical points properties revealing several dispersion assisted π-interactions and the most stable hydrogen bond interaction between the hydrogen of the GO hydroxyl groups and the oxygen of the PEO. MP2 results have been compared with five density functionals developed by Truhlar and Zhao (M05, M05-2X, M05-2X, M06-HF, and M06-L).