Synthesis and Mesomorphic Properties of a Series of Cholesteric Liquid Crystals

Abstract

A series of cholesterol liquid crystal compounds was synthesized. Phase-transition temperatures and mesomorphic textures of these synthesized compounds were characterized with differential scanning calorimetry and polarized optical microscopy, respectively. In these molecules the terminal ester chains CnH2n-1COO-, where n was the number of carbon atoms in the terminal ester chains, were linked to the cholesterol core. All of the synthesized cholesterol compounds exhibited mesophases for the first heating. However, as temperature decreased from their clearing points, their micrographs can also be divided into two categories, the first category exhibits branch-like mesophase textures for n in the range of 1-10 while the second category exhibits branch-like crystal textures for n in the range of 11-18.

One-Step Synthesis of a Liquid Crystal TB4A at Room Temperature

“…Using capillary method, the TB4A was filled into a LC cell whose spacing was measured to be about ten micrometers. The optical textures of the TB4A were investigated with a POM (Aipha Technologies, China) with a homemade hot stage [5][6][7][8][9][10][11][12].…”

“…Using capillary method, the TB4A was filled into a LC cell whose spacing was measured to be about ten micrometers. The optical textures of the TB4A were investigated with a POM (Aipha Technologies, China) with a homemade hot stage[5][6][7][8][9][10][11][12].The spectroscopic data are listed below for the TB4A:1 H NMR (500 MHz, CDCl 3 , δ/ppm): 8.53 (2H, s, 2HC=N), 7.99 (4H, s, 4Ar-H), 7.18-7.25 (8H, m, 8Ar-H), 2.62-2.65 (4H, t, 2CH 2 -Ar), 1.59-1.65 (4H, m, 2CH 2 ), 1.34-1.41 (4H, m, 2CH 2 -), 1.13-1.94 (6H, t, 2CH 3 ). FTIR (KBr, cm -1 ): 3023 (=C-H); 2956-2853(-CH 3 , -CH 2 -); 1622 (HC=N); 1599, 1560, 1497, 1464, 1417 (Ar-).…”