Synthesis And Characterization Of Side-chain Liquid Crystalline Elastomers Containing Perfluorocarbon Groups

It is well known that liquid crystalline elastomers （LCEs） are directed towards the development of multifunctional and oriented structures and has properties of high strength, high modulus, high-temperature resistant, low coefficient of expansion, low shrinkage shape, low density and excellent dielectric, chemical resistance, flame retardance and so on. These most outstanding characteristic of mechanical oriented ability can be applied in many fields. In the field of polymeric liquid crystals, side chain liquid crystal polymer is important. The side chain liquid crystal polymers have been investigated in recent years, such as acrylic polymer, polysiloxane, epoxy, and chitin. Although many liquid crystal materials have been developed, they are not suitable for display, because the liquid crystal materials for display require wide temperature range, low voltage, and fast response time. Therefore, the development of liquid crystal material with large An value, low viscosity, high△εvalue, miscibility under low temperature is one of the most important researches. Fluorine atom has electronic effect, simulative effect, obstructed effect, penetrative effect, higher negative charge effect and other special characters, which enable the liquid crystal with fluorine to be dipole. Thus, the liquid crystal material with fluorine is very important.Some liquid crystal monomers were synthesized: 4 - （acrylic ethoxy ester） benzoic acid, acrylic isosorbide ester, 4 - （acrylic ethoxy ester） benzoyloxy benzoic acid, 4 - （acrylic ethoxy ester） benzoic acid cholesterol ester and the characterization of their molecular structures were also tested. The fluoride has been introduced to the liquid crystal polymer according to bond polymerization reaction. Two types of fluoride SLCP materials were synthesized: 4 - （acrylic ethoxy ester） benzolyloxy benzoic acid with the fluoride SLCP and 4 - （acrylic ethoxy ester） benzoic acid cholesterol ester with the fluoride. Their molecular structures were characterized through IR, ¹HNMR, ¹⁹FNMR.With DSC and organizational structure analysis of liquid crystal polymers, it shows that 4 - （acrylic ethoxy ester） benzolyloxy benzoic acid with the fluoride SLCP is the nematic liquid crystal texture patterns and 4 - （acrylic ethoxy ester） benzoic acid cholesterol ester with the fluoride SLCP is the cholesterol liquid crystal texture patterns. 4 - （acrylic ethoxy ester） benzolyloxy benzoic acid with the fluoride SLCP has properties of high melting point,high cleaning point, wide range of phase change. This liquid crystal polymer is suitable for using in the wide temperature range liquid crystal material. 4 - （acrylic ethoxy ester） benzoic acid cholesterol ester with the fluoride SLCP has properties of low melting point, low cleaning point、narrow range of phase change. This liquid crystal polymer is suitable for using in low-bright point liquid crystal material.Liquid crystal polymer with fluorine is synthesized, which made tropism of liquid units in liquid crystal polymer much more stable .Thus the fluoride SLCP with fluoride polymer liquid crystal side chains is obtained, which has wide temperature range and very significant liquid crystal performance.