G. Johansson, V. Percec, G. Ungar
Jan 16, 1997
Citations
1
Influential Citations
95
Citations
Quality indicators
Journal
Chemistry of Materials
Abstract
4-Substituted n-5,5,6,6,7,7,8,8,9,9,10,10,10-tridecafluorododecan-1-yloxybenzenes, n-5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heptadecafluorododecan-1-yloxybenzenes, and 2-methyl-4-substituted n-5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heptadecafluorododecan-1-yloxybenzenes were synthesized and characterized by a combination of techniques consisting of differential scanning calorimetry (DSC), thermal optical polarized microscopy, and small- and wide-angle X-ray diffraction. Thermotropic sA and sC LC phases are exhibited by compounds with NO2, CN, CO2CH3, CH2OH, CO2H, and COCH3 substituents in the 4-position of the benzene ring. The thermal stability of the LC phase of these compounds increases with the increase of the length of the perfluorinated segment of their alkoxy group. A ratio of the perhydrogenated [(CH2)m]/perfluorinated [F(CF2)n] segment lengths of m/n < 1 favors the formation of LC phases when n + m = 10 and 12. Additional substitution in the 2-position of the benzene ring with a methyl group ...