Orientational ordering of alkyl chain at the air/liquid interface of ionic liquids studied by sum frequency vibrational spectroscopy

Adsorption of 1-Decyl-3-methylimidazolium Bromide and Solvation Structure of Bromide at the Air/Water Interface

“…3, a side by side arrangement of the ion pair at the surface is possible in principle even at the maximum adsorption. Such a side by side arrangement has been reported with respect to the adsorbed films of imidazorium ionic liquids having BF4 -as their counter ion on the basis of the results of the sum frequency generation method applied to the adsorbed film, 19 the phase diagram of adsorption of an ionic liquid and alcohol mixture, 22 and the surface properties of neat ionic liquids. 23 Therefore, it is an important issue to get information on the location of Br -at the air/water interface and then on the difference of distributions at the interface among counter ion species.…”

“…15 Actually many reports have been published with respect to surface properties and structures not only of neat ILs but also of their aqueous solutions. [16][17][18][19][20][21][22][23][24][25] Nevertheless, researches on the surface properties and structures of IL systems are not satisfactory but rather have just started in these last few years. The present study was performed with a view to elucidating the adsorption of 1-decyl-3-methylimidazolium bromide (DeMIMB), a typical of IL, at the air/water surface from the viewpoints of the macroscopic thermodynamic quantity such as surface excess concentration and the molecular level structure such as the coordination number of bromide ions.…”

Vibrational Spectroscopy for Studying Hydrogen Bonding in Imidazolium Ionic Liquids and their Mixtures with Cosolvents

“…In particular, sum-frequency generation (SFG) is a useful tool for investigating interfaces between ionic liquids and gases [46,47], liquids [48] and solids [49,50]. Moreover, time-resolved coherent anti-Stokes Raman scattering (CARS) will facilitate studying ionic liquids in excited vibrational states.…”

Surface of room temperature ionic liquid [bmim][PF6] studied by polarization- and experimental configuration-dependent sum frequency generation vibrational spectroscopy

“…Owing to these excellent technical advantages, RTILs have shown great potentials in a variety of applications, including catalysis [6], electrochemistry [7], synthesis [8], separation [9], and green chemistry [10], many of which involve chemical or physical processes on the RTIL surface. As a result, a great number of experimental and theoretical efforts have been made to investigate the surface structure of ionic liquids using various techniques such as surface tension measurements [11], X-ray/neutron reflectivity [12,13], sum frequency generation vibrational spectroscopy (SFG-VS) [14][15][16] and molecular dynamics (MD) simulations [17][18][19][20]. In this study, the polarization and experimental configuration-dependent SFG-VS was employed to explore the orientational structures of the interfacial 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]) on a molecular level.…”

“…Baldelli's group [14] and Kim's group [15] carried out some of the pioneering SFG-VS studies on the molecular orientations of interfacial [bmim][PF 6 ] and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim] [BF 4 ]). Both reported that the butyl chain protrudes into the air.…”