Force Fields for Modeling of Ionic Liquids

The primary objective of the proposed work is to develop and validate a transferable force field that will allow for reliable, accurate and efficient prediction of thermodynamic (heat of vaporization, surface tension, density, melting temperature), transport (viscosity, ionic and thermal conductivity, self-diffusion coefficients) and structural properties for a wide variety of ionic liquids (ILs) with potential applications as hypergolic propellants, high energy explosives, insensitive munitions, and in non-energetic applications such as energy storage, gas storage, separations, lubrication and actuators.   Due to the demonstrated transferability of polarizable potentials, the core of our approach will be development of an atomistic polarizable force field applicable to a very broad set of ILs.  Because of the expense of many-body polarizable simulations compared to those using non-polarizable models (a factor of 2-4), a force field hierarchy for ILs will be developed via systematic parameterization of computationally less expensive two-body non-polarizable force fields and united atom non-polarizable force fields.  These force fields will be parameterized to reproduce as accurately as possible the structure, thermodynamics and transport properties of ILs obtained from simulations performed with highly accurate but more computationally expensive transferable potential. BENEFIT: Molecular Dynamics (MD) simulations utilizing the developed force fields will enable expedient and accurate prediction of IL properties resulting in acceleration of the development cycle for novel materials with potential applications in a variety of industries ranging from defense to energy production and storage to mitigation of climate change. The transferable polarizable potential will be incorporated into a force field database called Atomistic Polarizable Potential for Liquids, Electrolytes and Polymers (APPLE&P) that is currently being commercialized by Wasatch Molecular Inc.  This potential will be compatible with several commonly used simulation packages including Lucretius, AMBER, LAMMPS and TINKER, and will be marketed both alone and in conjunction with Lucretius.  Non-polarizable versions of the potential will be marketed in forms compatible with all major simulation packages.  We are actively seeking to develop marketing relationships for both APPLE&P and Lucretius with various modeling software firms.