Neutron scattering studies on short- and long-range layer structures and related dynamics in imidazolium-based ionic liquids
-
- Fumiya Nemoto
- Institute for Solid State Physics, University of Tokyo 1 , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
-
- Maiko Kofu
- Institute for Solid State Physics, University of Tokyo 1 , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
-
- Michihiro Nagao
- NIST Center for Neutron Research, National Institute of Standards and Technology 3 , 100 Bureau Drive, Gaithersburg, Maryland 20899-6102, USA
-
- Kazuki Ohishi
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS) 5 , IQBRC Bldg., 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
-
- Shin-ichi Takata
- J-PARC Center, Japan Atomic Energy Agency 2 , 2-4 Shirakata, Tokai, Naka, Ibaraki 319-1195, Japan
-
- Jun-ichi Suzuki
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS) 5 , IQBRC Bldg., 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
-
- Takeshi Yamada
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS) 5 , IQBRC Bldg., 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
-
- Kaoru Shibata
- J-PARC Center, Japan Atomic Energy Agency 2 , 2-4 Shirakata, Tokai, Naka, Ibaraki 319-1195, Japan
-
- Takeshi Ueki
- Department of Materials Engineering, University of Tokyo 6 , 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
-
- Yuzo Kitazawa
- Department of Chemistry and Biotechnology, Yokohama National University 7 , 79-5 Tokiwadai, Hodogaya, Yokohama, Kanagawa 240-8501, Japan
-
- Masayoshi Watanabe
- Department of Chemistry and Biotechnology, Yokohama National University 7 , 79-5 Tokiwadai, Hodogaya, Yokohama, Kanagawa 240-8501, Japan
-
- Osamu Yamamuro
- Institute for Solid State Physics, University of Tokyo 1 , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
この論文をさがす
説明
<jats:p>Alkyl-methyl-imidazolium ionic liquids CnmimX (n: alkyl-carbon number, X: anion) have short-range layer structures consisting of ionic and neutral (alkylchain) domains. To investigate the temperature dependences of the interlayer, interionic group, and inter-alkylchain correlations, we have measured the neutron diffraction (ND) of C16mimPF6, C9.5mimPF6, and C8mimPF6 in the temperature region from 4 K to 470 K. The quasielastic neutron scattering (QENS) of C16mimPF6 was also measured to study the dynamics of each correlation. C16mimPF6 shows a first-order transition between the liquid (L) and liquid crystalline (LC) phases at Tc = 394 K. C8mimPF6 exhibits a glass transition at Tg = 200 K. C9.5mimPF6, which is a 1:3 mixture between C8mimPF6 and C10mimPF6, has both transitions at Tc = 225 K and Tg = 203 K. In the ND experiments, all samples exhibit three peaks corresponding to the correlations mentioned above. The widths of the interlayer peak at ca. 0.2 Å−1 changed drastically at the L-LC transitions, while the interionic peaks at ca. 1 Å−1 exhibited a small jump at Tc. The peak position and area of the three peaks did not change much at the transition. The structural changes were minimal at Tg. The QENS experiments demonstrated that the relaxation time of the interlayer motion increased tenfold at Tc, while those of other motions were monotonous in the whole temperature region. The structural and dynamical changes mentioned above are characteristic of the L-LC transition in imidazolium-based ionic liquids.</jats:p>
収録刊行物
-
- The Journal of Chemical Physics
-
The Journal of Chemical Physics 149 (5), 054502-, 2018-08-02
AIP Publishing
