Author ORCID Identifier

https://orcid.org/0000-0003-2244-5505

Year of Publication

2020

Degree Name

Master of Science in Mechanical Engineering (MSME)

Document Type

Master's Thesis

College

Engineering

Department

Mechanical Engineering

First Advisor

Dr. Sergiy Markutsya

Second Advisor

Dr. Y. Charles Lu

Abstract

Ionic liquids, possessing improved properties in many areas of technical application, are excellent candidates as components in development of next-generation technology, including ultra-high energy batteries. If they are thus applied, however, extensive interfacial analysis of any selected ionic configuration will likely be required. Molecular dynamics (MD) provides an advantageous route by which this may be accomplished, but can fall short in observing some phenomena only present at larger time/length scales than it can simulate. Often times this is approached by coarse-graining (CG), with which scope of simulation can be significantly increased. However, coarse-grained MD systems are generally known to produce inaccurately “fast” dynamics. In this work, two different sets of ionic liquid pairs are coarse-grained from atomistic MD reference systems, expanding their system size and time duration capabilities for analysis at vacuum-interface. The dynamics of each system are corrected using the novel in-house probability distribution function coarse-graining (PDF-CG) method. The bonded structure, non-bonded structure and dynamics of each system are developed and proven to match reference system data at two temperature scales. Density profile results of vacuum-interface exposure show effects of both temperature scaling and CG method, varying significantly from bulk behavior. At the interface, a density increase, cation orientations and multilayer ordering are observed.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2020.086

Funding Information

This research was supported by NASA Kentucky under NASA award No: NNX15AR69H awarded for 2019.

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