Syntheses of highly twisted helical polyacetylene under nano-order chiral nematic liquid crystal reaction field 948-951

• Published in: Current applied physics pp. 948 - 951
• Main Authors: M.J. Goh, M. Kyotani, K. Akagi
• Format: Journal Article
• Language: Korean
• Published: 한국물리학회 01-09-2006
• Subjects: 물리학
• ISSN: 1567-1739; 1878-1675

We synthesized novel mesogenic axially chiral binaphthyl derivative by substituting phenyl-cyclohexyl (PCH) moieties into 2, 20,6 and 60 positions of binaphthyl rings. The binaphthyl derivative showed the highest twisting power ofbM = 381.87 l m. 1, when0.05 mol% of the chiral dopant was added into a mixture of PCH302 and PCH304. The helical pitches of N*-LC varied from270 to 350 nm with changes of the concentration of the chiral dopant from 1.5 to 1.0 mol%. These helical pitches are smallerone-tenth than those (25l m) observed in the N*-LC containing di-substituted binaphthyl derivatives. This indicates that the pres-ent N*-LC including tetra-substituted binaphthyl derivatives is feasible for much higher twisted asymmetric reaction eld. It is ofinterest that the polyacetylene lm synthesized in the N*-LC with helical pitch of 270 nm showed highly screwed brils, but notthe bundle of bril. This is due to the fact that the helical pitch of 270 nm is smaller than the diameter of the bundle of bril. Thissituation might depress the formation of the bundle of bril. The brillar morphology without the bundle of brils should make it much easier to evaluate electromagnetic properties of the screwed fibril. KCI Citation Count: 15