Ab Initio Study of Proton Transfer and Interfacial Properties in Phosphoric Acid-Doped Polybenzimidazole

Ab initio study of hydrogen bonding in the H3PO2 dimer and H3PO2-DMF complex

The molecular structures and H-bonding interactions in the phosphinic acid dimer and the complex of phosphinic acid with N,N-dimethylformamide (DMF) were investigated by density functional theory calculations at the B3LYP level of theory. In order to better understand these phenomena, the individual molecules were also studied. The results were compared with previously obtained data for similar H-bonded complexes of phosphoric and phosphorous acids with DMF. Various correlations were found between geometric characteristics and parameters derived from Bader's theory and natural bond orbital analysis. Graphical abstract Irina V. Fedorova and Lyubov P. Safonova. Ab initio study of hydrogen bonding in the H₃PO₂ dimer and H₃PO₂-DMF complex. The acids of phosphorus are considered suitable candidates for ionomers due to their efficient proton transport properties. In order to better understand their molecular structures and their H-bond characteristics in real liquids, the most stable configurations of the H₃PO₂ dimer and the H₃PO₂-DMF complex were examined using computational methods in quantum chemistry. It was found that the strength of the H-bonding interactions in these systems depends strongly on the environment.

Ab initio molecular dynamics study of H-bonding and proton transfer in the phosphoric acid-N,N-Dimethylformamide system

Car-Parrinello molecular dynamics simulations of phosphoric acid (H₃PO₄)-N,N-dimethylformamide (DMF) mixtures over the whole composition range have been carried out. It has been found that the neutral molecules are the dominant species in this system. The concentration dependences of the average number of H-bonds per proton acceptor atom in P=O and C=O groups as well as per proton donor atom in DMFH⁺ ions towards phosphate species have been discussed. The H-bonding between components in all investigated mixtures of H₃PO₄ and DMF is possible. A significant fraction of the protonated DMF forms appears at phosphoric acid mole fraction higher than 0.37, indicating a high probability of proton transfer from phosphate species to oxygen atoms in C=O groups. The intermolecular proton transfer between phosphate species themselves is mainly observed when x_H3PO4 > 0.19. Satisfactory agreement with available experimental data for structural characteristics of the investigated system was obtained.

Exploring the hydrated microstructure and molecular mobility in blend polyelectrolyte membranes by quantum mechanics and molecular dynamics simulations

QMs and MD simulations were employed to investigate the effect of water contents and temperatures on structural and dynamical behaviors of blended PEMs.