TY - JOUR
T1 - Surface behaviour of 1-alkyl-3-methylimidazolium ionic liquids at the air-water interface
AU - Taßler, Stephanie
AU - Bonatout, Nathalie
AU - Eusébio, Tiago M.
AU - Valente, Raquel M.
AU - Rego, Tomás
AU - Ibrahim, Helen
AU - Morgado, Pedro
AU - Filipe, Eduardo J.M.
AU - Goldmann, Michel
AU - Fontaine, Philippe
N1 - Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2023/1/15
Y1 - 2023/1/15
N2 - The ability of 1-alkyl-3-methylimidazolium ionic liquids, [Cnmim][X], to form layers at the air–water interface has been investigated systematically for the first time: five different chain lengths of the cation, n = 12, 14, 16, 18, 20 were studied, combined with three different anions, namely [N(Tf)2]−, [PF6]− and [Cl]−. The results show that only cations with chains longer than n = 16, combined with the [N(Tf)2]− anion form stable monolayers at the air/water interface, allowing measurable surface pressure vs area per molecule (π-A) isotherms immediately after spreading. The films of [C20mim][N(Tf)2] on water have been characterised using Brewster angle microscopy (BAM), Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS), specular X-ray reflectivity (XRR) and grazing incidence X-ray diffraction (GIXD). Additionally, atomistic molecular dynamics simulations were also performed to obtain a molecular level interpretation of the experimental results. The results are compatible with a transition from an expanded monolayer to a trilayer structure, followed by the 3D collapse of the film.
AB - The ability of 1-alkyl-3-methylimidazolium ionic liquids, [Cnmim][X], to form layers at the air–water interface has been investigated systematically for the first time: five different chain lengths of the cation, n = 12, 14, 16, 18, 20 were studied, combined with three different anions, namely [N(Tf)2]−, [PF6]− and [Cl]−. The results show that only cations with chains longer than n = 16, combined with the [N(Tf)2]− anion form stable monolayers at the air/water interface, allowing measurable surface pressure vs area per molecule (π-A) isotherms immediately after spreading. The films of [C20mim][N(Tf)2] on water have been characterised using Brewster angle microscopy (BAM), Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS), specular X-ray reflectivity (XRR) and grazing incidence X-ray diffraction (GIXD). Additionally, atomistic molecular dynamics simulations were also performed to obtain a molecular level interpretation of the experimental results. The results are compatible with a transition from an expanded monolayer to a trilayer structure, followed by the 3D collapse of the film.
KW - 1-Alkyl-3-methylimidazolium ionic liquids
KW - GIXD
KW - IRRAS
KW - Langmuir monolayer
KW - MD Simulations
KW - XRR
UR - https://www.scopus.com/pages/publications/85144319250
UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=pure_univeritat_ramon_llull&SrcAuth=WosAPI&KeyUT=WOS:000906514800001&DestLinkType=FullRecord&DestApp=WOS_CPL
U2 - 10.1016/j.molliq.2022.121028
DO - 10.1016/j.molliq.2022.121028
M3 - Article
AN - SCOPUS:85144319250
SN - 0167-7322
VL - 370
JO - Journal of Molecular Liquids
JF - Journal of Molecular Liquids
M1 - 121028
ER -