Thermal and Structural Studies of Imidazolium-Based Ionic Liquids with and without Liquid-Crystalline Phases: The Origin of Nanostructure

被引:58
作者
Nemoto, Fumiya [1 ]
Kofu, Maiko [1 ]
Yamamuro, Osamu [1 ]
机构
[1] Univ Tokyo, Inst Solid State Phys, Kashiwa, Chiba 2778581, Japan
关键词
ALKYL CHAIN-LENGTH; X-RAY-SCATTERING; 1-ALKYL-3-METHYLIMIDAZOLIUM HEXAFLUOROPHOSPHATE; SPATIAL HETEROGENEITY; BEHAVIOR; DYNAMICS; CHLORIDE; SALTS; TRANSITION; MIXTURES;
D O I
10.1021/acs.jpcb.5b01080
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
To clarify the origin of the nanostructure of ionic liquids (ILs), we have investigated two series of ILs 1-alkyl-3-methylimidazolium hexafluorophosphate (CnmimPF(6), n = 4-16, n is an alkyl-carbon number) and 1-alkyl-3-methylimidazolium chloride (CnmimCl, n = 4-14) using differential scanning calorimetry and X-ray diffraction techniques. The PF6 samples with n > 13 and the Cl samples with n > 10 exhibited the liquid-crystalline (LC) to liquid (L) phase transitions, as reported before. We found that both samples with smaller n also exhibited the LC to L transitions under supercooled states as far as the ionic motions were not frozen-in at the glass transition temperatures T-g. The T-g of the LC phase was close to that of the L phase, indicating that the characteristic length of the glass transition is shorter than that of the nanostructure. A low-Q peak due to the nanostructure in the L phase and a diffraction peak due to the layer structure in the LC phase appeared at almost the same Q positions in both samples. On the basis of the above results and some thermodynamic analysis, we argue that the nanostructures of ILs are essentially the same as the layer structures in the LC phases.
引用
收藏
页码:5028 / 5034
页数:7
相关论文
共 45 条
  • [1] What is the Origin of the Prepeak in the X-ray Scattering of Imidazolium-Based Room-Temperature Ionic Liquids?
    Annapureddy, Harsha V. R.
    Kashyap, Hemant K.
    De Biase, Pablo M.
    Margulis, Claudio J.
    [J]. JOURNAL OF PHYSICAL CHEMISTRY B, 2010, 114 (50) : 16838 - 16846
  • [2] Nanoscale heterogeneity in alkyl-methylimidazolium bromide ionic liquids
    Aoun, Bachir
    Goldbach, Andreas
    Gonzalez, Miguel A.
    Kohara, Shinji
    Price, David L.
    Saboungi, Marie-Louise
    [J]. JOURNAL OF CHEMICAL PHYSICS, 2011, 134 (10)
  • [3] Heat capacities and phase transitions of the antiferroelectric liquid crystals MHPOBC and MHPOCBC
    Asahina, S
    Sorai, M
    Fukuda, A
    Takezoe, H
    Furukawa, K
    Terashima, K
    Suzuki, Y
    Kawamura, I
    [J]. LIQUID CRYSTALS, 1997, 23 (03) : 339 - 348
  • [4] Liquid-crystalline ionic liquids
    Bowlas, CJ
    Bruce, DW
    Seddon, KR
    [J]. CHEMICAL COMMUNICATIONS, 1996, (14) : 1625 - 1626
  • [5] Small-angle X-ray scattering studies of liquid crystalline 1-alkyl-3-methylimidazolium salts
    Bradley, AE
    Hardacre, C
    Holbrey, JD
    Johnston, S
    McMath, SEJ
    Nieuwenhuyzen, M
    [J]. CHEMISTRY OF MATERIALS, 2002, 14 (02) : 629 - 635
  • [6] A physicochemical investigation of ionic liquid mixtures
    Clough, Matthew T.
    Crick, Colin R.
    Grasvik, John
    Hunt, Patricia A.
    Niedermeyer, Heiko
    Welton, Tom
    Whitaker, Oliver P.
    [J]. CHEMICAL SCIENCE, 2015, 6 (02) : 1101 - 1114
  • [7] Correlating Structure with Thermal Properties for a Series of 1-Alkyl-4-methyl-1,2,4-triazolium Ionic Liquids
    Daily, Lucas A.
    Miller, Kevin M.
    [J]. JOURNAL OF ORGANIC CHEMISTRY, 2013, 78 (08) : 4196 - 4201
  • [8] de Gennes P. G., 2002, International Series of Monographs on Physics, V2nd
  • [9] Application of complementary experimental techniques to characterization of the phase behavior of [C16mim][PF6] and [C14mim][PF6]
    De Roche, J
    Gordon, CM
    Imrie, CT
    Ingram, MD
    Kennedy, AR
    Lo Celso, F
    Triolo, A
    [J]. CHEMISTRY OF MATERIALS, 2003, 15 (16) : 3089 - 3097
  • [10] Solubility of 1-alkyl-3-methylimidazolium hexafluorophosphate in hydrocarbons
    Domanska, U
    Marciniak, A
    [J]. JOURNAL OF CHEMICAL AND ENGINEERING DATA, 2003, 48 (03) : 451 - 456