Molecular Ordering of Organic Molten Salts Triggered by Single-Walled Carbon Nanotubes
Takanori Fukushima,1*
Atsuko Kosaka,1
Yoji Ishimura,2
Takashi Yamamoto,2
Toshikazu Takigawa,2
Noriyuki Ishii,3
Takuzo Aida1*
When mixed with imidazolium ion-based room-temperature ionic liquid, pristine single-walled carbon nanotubes formed gels after being ground. The heavily entangled nanotube bundles were found to untangle within the gel to form much finer bundles. Phase transition and rheological properties suggest that the gels are formed by physical cross-linking of the nanotube bundles, mediated by local molecular ordering of the ionic liquids rather than by entanglement of the nanotubes. The gels were thermally stable and did not shrivel, even under reduced pressure resulting from the nonvolatility of the ionic liquids, but they would readily undergo a gel-to-solid transition on absorbent materials. The use of a polymerizable ionic liquid as the gelling medium allows for the fabrication of a highly electroconductive polymer/nanotube composite material, which showed a substantial enhancement in dynamic hardness.
1 Aida Nanospace, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST), National Museum of Emerging Science and Innovation, 2-41 Aomi, Koto-ku, Tokyo 135–0064, Japan.
2 Department of Material Chemistry, Kyoto University, Sakyo-ku, Kyoto 606–8501, Japan.
3 Biological Information Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central-6, 1-1-1 Higashi, Tsukuba, Ibaraki 305–8566, Japan.
* To whom correspondence should be addressed. E-mail: fukushima{at}nanospace.miraikan.jst.go.jp (T.F.); aida{at}macro.t.u-tokyo.ac.jp (T.A.)
