Synthesis of novel and regioselectively mesogen-incorporated thermotropic liquid crystals from cellulose derivatives

ABSTRACT

Regioselectively mesogen-incorporated cellulose derivatives, in which the hydroxy group at C-6 is displaced by a bulky and rigid mesogenic group such as {4-[(4-methoxyphenoxy)carbonyl]phenoxy}acetate or [(4′-cyanobiphenyl-4-yl)oxy]acetate, and the C-2 and C-3 groups are displaced by octanoyl or lauroyl groups, were synthesized. Thermogravimetric and differential scanning calorimetric analyses of the final products, along with polarized optical microscopic observations, revealed that the obtained cellulose derivatives have a thermotropic liquid-crystalline nature and transition from the mesomorphic to the isotropic phase over a wide range of temperatures. These derivatives could be considered to be main-chain liquid-crystalline cellulosic polymers.

KEYWORDS:

• cellulose derivative
• thermotropic liquid crystal
• mesogen
• chiral resolution

Acknowledgments

The authors thank Lenzing Japan's marketing office for donating us the Tencel® fiber, and prof. Mikio Kajiyama at Tsukuba University and the staff of industrial technology center of Tochigi prefecture (at Sano-shi) for helpful advises and the use of analytical instruments in DSC measurements, respectively. The authors also thank the staff of center of the elemental analysis of organic compounds at Kyushu University and Enago (www.enago.jp) for the elementary analyses and the English language review, respectively.