Fine-grained and coarse-grained molecular dynamics simulations of ionic liquids and soft matter systems

Author(s)

Rafael Maglia de Souza

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC)
• Defense date: 2020-05-13

Examining board members

Luis Gustavo Dias; Guilherme Menegon Arantes; Kaline Rabelo Coutinho; Gustavo Troiano Feliciano; Eudes Eterno Fileti; Leonardo José Amaral de Siqueira

• Advisor: Luis Gustavo Dias

Abstract

In molecular mechanics, coarse-grained models map a set of atoms in a single interaction site. This reduction in the number of degrees of freedom of the system decreases the computational cost of the simulations and allows the study of systems on a wide space-time scale. In this context, the thesis presents extensions and applications of the coarse-grained ELBA force field for the following soft matter systems: micelles, bicelles, reverse micelles and amino acids. The results show that ELBA describes a series of geometric, thermodynamic and transport properties of the amphiphilic aggregates, in good agreement with fine-grained (atomistic) simulations or experiments. This thesis also presents a top-down coarse-grained model for the ionic liquid of 1-ethyl-3-methyl-imidazolium tetracyanoborate, calibrated to reproduce experimental data of density, viscosity and diffusion coefficients of the ionic species as a function of temperature. The coarse-grained model complements the fine-grained molecular dynamics study carried out for the same ionic liquid, thought of as an electrolytic medium for sodium or potassium ion batteries. In the fine-grained simulations, thermodynamic and transport properties of this electrolyte were evaluated in different amounts of sodium or potassium salts and polyethylene glycol (PEO6) molecules. The best conditions of the electrolyte (higher ionic conductivities and lower viscosities) occurred in low amounts of the alkali metal ion and PEO6. (AU)

• FAPESP's process: 17/26102-5 - Computational simulation of the electrolytic medium of secondary alkali and/or alkaline earth metal ion batteries
• Grantee: Rafael Maglia de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate