Molecular Modeling of Poly(Ethylene Oxide) Melts and Poly(Ethylene Oxide)-Based Polymer Electrolytes

Property structure relationships in materials can be studied by a number of computational approaches such as ab initio quantum chemistry calculations, ab initio molecular dynamics (MD) simulations, classical MD and Monte-Carlo simulations, finite element modelling, etc. A choice of the computational method depends on the time and length scales and computational resources available. At the current stage of method and hardware development, ab initio quantum chemistry calculations are best suited for studying energy-structure relationships in relatively small systems consisting of tens of atoms. Ab initio MD simulations allow one to study dynamics of systems on a picosecond time scale for systems consisting of hundreds of atoms. Energy and forces in ab initio MD simulations are obtained from solving the electronic structure problem “on the fly”. Parameterization of the energy a system as a function of the relative atom positions, e. g., development of a classical force field, significantly speeds up calculations of the energies and forces in MD simulations, positioning classical MD simulations as the most suitable tool to obtain properties of the systems containing 10-10 atoms on the time scales from 10 to 10 s. However, the value of the property predictions using classical MD simulations is limited to the accuracy of the force field used, making a consistent derivation of a high quality classical force fields central to accurate prediction of the property-structure relationship from MD simulations.