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Title: Computational Studies of [Bmim][PF6]/n-Alcohol Interfaces with Many-Body Potentials

Abstract

In this paper, we present the results from molecular-dynamics simulations of the equilibrium properties of liquid/liquid interfaces of room temperature ionic liquid [bmim][PF6] and simple alcohols (i.e., methanol, 1-butanol, and 1-hexanol) at room temperature. Polarizable potential models are employed to describe the interactions among species. Results from our simulations show stable interfaces between the ionic liquid and n-alcohols, and we found that the interfacial widths decrease from methanol to 1-butanol systems, and then increase for 1-hexanol interfaces. Angular distribution analysis reveals that the interface induces a strong orientational order of [bmim] and n-alcohol molecules near the interface, with [bmim] extending its butyl group into the alcohol phase while the alcohol has the OH group pointing into the ion liquid region, which is consistent with the recent sum-frequency-generation experiments. We found the interface to have a significant influence on the dynamics of ionic liquids and n-alcohols. The orientational autocorrelation functions illustrate that [bmim] rotate more freely near the interface than in the bulk, while the rotation of n-alcohol is hindered at the interface. Additionally, the time scale associated with the diffusion along the interfacial direction is found to be faster for [bmim] but slowed down for n-alcohols approaching the interface. Wemore » also calculate the dipole moment of n-alcohols as a function of the distance normal to the interface. We found that, even though methanol and 1-butanol have different dipole moments in bulk phase, they reach a similar value at the interface. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for the Department of Energy by Battelle. The calculations were carried out using computer resources provided by the Office of Basic Energy Sciences.« less

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1168886
Report Number(s):
PNNL-SA-96379
KC0301020
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A, 118(35):7186-7193
Additional Journal Information:
Journal Name: Journal of Physical Chemistry A, 118(35):7186-7193
Country of Publication:
United States
Language:
English

Citation Formats

Chang, Tsun-Mei, and Dang, Liem X. Computational Studies of [Bmim][PF6]/n-Alcohol Interfaces with Many-Body Potentials. United States: N. p., 2014. Web. doi:10.1021/jp405910k.
Chang, Tsun-Mei, & Dang, Liem X. Computational Studies of [Bmim][PF6]/n-Alcohol Interfaces with Many-Body Potentials. United States. https://doi.org/10.1021/jp405910k
Chang, Tsun-Mei, and Dang, Liem X. 2014. "Computational Studies of [Bmim][PF6]/n-Alcohol Interfaces with Many-Body Potentials". United States. https://doi.org/10.1021/jp405910k.
@article{osti_1168886,
title = {Computational Studies of [Bmim][PF6]/n-Alcohol Interfaces with Many-Body Potentials},
author = {Chang, Tsun-Mei and Dang, Liem X.},
abstractNote = {In this paper, we present the results from molecular-dynamics simulations of the equilibrium properties of liquid/liquid interfaces of room temperature ionic liquid [bmim][PF6] and simple alcohols (i.e., methanol, 1-butanol, and 1-hexanol) at room temperature. Polarizable potential models are employed to describe the interactions among species. Results from our simulations show stable interfaces between the ionic liquid and n-alcohols, and we found that the interfacial widths decrease from methanol to 1-butanol systems, and then increase for 1-hexanol interfaces. Angular distribution analysis reveals that the interface induces a strong orientational order of [bmim] and n-alcohol molecules near the interface, with [bmim] extending its butyl group into the alcohol phase while the alcohol has the OH group pointing into the ion liquid region, which is consistent with the recent sum-frequency-generation experiments. We found the interface to have a significant influence on the dynamics of ionic liquids and n-alcohols. The orientational autocorrelation functions illustrate that [bmim] rotate more freely near the interface than in the bulk, while the rotation of n-alcohol is hindered at the interface. Additionally, the time scale associated with the diffusion along the interfacial direction is found to be faster for [bmim] but slowed down for n-alcohols approaching the interface. We also calculate the dipole moment of n-alcohols as a function of the distance normal to the interface. We found that, even though methanol and 1-butanol have different dipole moments in bulk phase, they reach a similar value at the interface. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for the Department of Energy by Battelle. The calculations were carried out using computer resources provided by the Office of Basic Energy Sciences.},
doi = {10.1021/jp405910k},
url = {https://www.osti.gov/biblio/1168886}, journal = {Journal of Physical Chemistry A, 118(35):7186-7193},
number = ,
volume = ,
place = {United States},
year = {Thu Sep 04 00:00:00 EDT 2014},
month = {Thu Sep 04 00:00:00 EDT 2014}
}