TY - JOUR
T1 - Investigation of Multilayered Structures of Ionic Liquids on Graphite and Platinum Using Atomic Force Microscopy and Molecular Simulations
AU - Chen, Zhichao
AU - Li, Zixuan
AU - Zhao, Wei
AU - Matsumoto, Ray A.
AU - Thompson, Matthew W.
AU - Morales-Collazo, Oscar
AU - Cummings, Peter T.
AU - Mangolini, Filippo
AU - Brennecke, Joan F.
N1 - Funding Information:
This research (J.F.B., O.M.-C., and Z.C.) was funded by the Robert A. Welch Foundation (grant no. F-1945-20180324). These authors also thank Toyota Motor Engineering & Manufacturing North America, Inc. for financial support and technical discussions. In addition, the authors would like to acknowledge NIH (no. 1 S10 OD021508-01) for funding of the Bruker Avance III 500 NMR. The MD simulations and their analysis were supported as part of the Fluid Interface Reactions, Structures, and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. The MD calculations used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under contract no. DE-AC02-05CH11231. F.M. acknowledges support from the Robert A. Welch Foundation (grant no. F-2002-20190330) and the National Science Foundation Faculty Early Career Development Program (grant no. 2042304).
Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022/4/5
Y1 - 2022/4/5
N2 - The molecular-level orientation and structure of ionic liquids (ILs) at liquid-solid interfaces are significantly different than in the bulk. The interfacial ordering influences both IL properties, such as dielectric constants and viscosity, and their efficacy in devices, such as fuel cells and electrical capacitors. Here, we report the layered structures of four ILs on unbiased, highly ordered pyrolytic graphite (HOPG) and Pt(111) surfaces, as determined by atomic force microscopy. The ILs investigated are 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]), 1-ethyl-3-methylimidazolium perfluorobutylsulfonate ([emim][C4F9SO3]), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene bis(trifluoromethylsulfonyl)imide ([MTBD][Tf2N]), and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene perfluorobutylsulfonate ([MTBD][C4F9SO3]). Molecular dynamics simulations provide complementary information on the position and orientation of the ions. These ILs form a cation layer at the IL-solid interface, followed by a layer of anions. [Emim]+and [MTBD]+have similar orientations at the surface, but [MTBD]+forms a thinner layer compared to [emim]+on both HOPG and Pt(111).
AB - The molecular-level orientation and structure of ionic liquids (ILs) at liquid-solid interfaces are significantly different than in the bulk. The interfacial ordering influences both IL properties, such as dielectric constants and viscosity, and their efficacy in devices, such as fuel cells and electrical capacitors. Here, we report the layered structures of four ILs on unbiased, highly ordered pyrolytic graphite (HOPG) and Pt(111) surfaces, as determined by atomic force microscopy. The ILs investigated are 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]), 1-ethyl-3-methylimidazolium perfluorobutylsulfonate ([emim][C4F9SO3]), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene bis(trifluoromethylsulfonyl)imide ([MTBD][Tf2N]), and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene perfluorobutylsulfonate ([MTBD][C4F9SO3]). Molecular dynamics simulations provide complementary information on the position and orientation of the ions. These ILs form a cation layer at the IL-solid interface, followed by a layer of anions. [Emim]+and [MTBD]+have similar orientations at the surface, but [MTBD]+forms a thinner layer compared to [emim]+on both HOPG and Pt(111).
UR - http://www.scopus.com/inward/record.url?scp=85127305370&partnerID=8YFLogxK
U2 - 10.1021/acs.langmuir.2c00024
DO - 10.1021/acs.langmuir.2c00024
M3 - Article
C2 - 35313730
AN - SCOPUS:85127305370
SN - 0743-7463
VL - 38
SP - 4036
EP - 4047
JO - Langmuir
JF - Langmuir
IS - 13
ER -