"Bicontinuous cubic" liquid crystalline materials from discotic molecules: a special effect of paraffinic side chains with ionic liquid pendants.
Triphenylene (TP) derivatives bearing appropriate paraffinic side chains with imidazolium ion-based ionic liquid (IL) pendants were unveiled to display a phase diagram with liquid crystalline (LC) mesophases of bicontinuous cubic (Cub(bi)) and hexagonal columnar (Col(h)) geometries. While their phase transition behaviors are highly dependent on the length of the side chains and the size of the ionic liquid pendants, TPs with hexadecyl side chains exclusively form a Cub(bi) LC assembly over an extremely wide temperature range of approximately 200 degrees C from room temperature when the anions of the IL pendants are relatively small. Wide-angle X-ray diffraction analysis suggested that the Cub(bi) LC mesophase contains pi-stacked columnar TP arrays with a plane-to-plane separation of approximately 3.5 A. Consistently, upon laser flash photolysis, it showed a transient microwave conductivity comparable to that of a Col(h) LC reference.
Alam
Md Akhtarul
MA
ERATO-SORST Nanospace Project, Japan Science and Technology Agency (JST), 2-41 Aomi, Koto-ku, Tokyo 135-0064, Japan.
Motoyanagi
Jin
J
Yamamoto
Yohei
Y
Fukushima
Takanori
T
Kim
Jungeun
J
Kato
Kenichi
K
Takata
Masaki
M
Saeki
Akinori
A
Seki
Shu
S
Tagawa
Seiichi
S
Aida
Takuzo
T
D002911:Chrysenes / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D015394:Molecular Structure; D010232:Paraffin / Q000737:chemistry*
D002911:Chrysenes; D052578:Ionic Liquids; C009590:triphenylene; D010232:Paraffin