Study On Preparation And Properties Of Fluorinated Chiral Side Liquid Crystalline Polymers

Fluorine atom has unique properties such as electronic effect, analog effects, obstacles and other special effects and the nature of osmosis effect, so the introduction of fluorine atom into will change many properties of liquid crystal. Fluorinate liquid crystal has low viscosity, high resistance rate, rapid response speed and higher dielectric constant, etc., with these excellent features, fluorinated liquid crystals have broad application prospects. The unique optical and electrical properties of chiral liquid crystal materials draw increasingly widespread attention. Due to the chiral centers such liquid crystal molecules present spiral structure, which lead to the unique optical properties of liquid crystal polymers than usual. The type of such liquid crystal was cholesteric or smectic phase.In this paper, five liquid crystalline monomers and two Chiral monomers were synthesized,which include:Cholestery undecylenate(M1),4’-(6-(4-fluorobenzamido)hexa-noloxy)biphenyl-4-yl4-(allyloxy)benzoate(M2),4’-(4-(allyloxy)benzoyloxy)biphenyl-4-yl (3S,3aR,6R,6aR)-6-(4-fluorobenzoyloxy)hexahydrofuro[3,2-b]furan-3-yladipate(M3),4’-(4-(al lyloxy)benzoyloxy)biphenyl-4-yl(3S,3aR,6R,6aR)-6-(6-(4-fluorobenzamido)hexanoyloxy)he xahydrofuro[3,2-b]furan-3-yladipate(M4),(3S,3aR,6R,6aR)-6-(4-fluorobenzoyloxy)hexahydro furo[3,2-b]furan-3-yl4’-(undec-10-enoyloxy)biphenyl-4-yladipate(M5),4’-(allyloxy)biphenyl-4-yl(3S,3aR,6R,6aR)-6-(4-fluorobenzoyloxy)hexahydrofuro[3,2-b]furan-3-yladipate(M6),4’-(al lyloxy)biphenyl-4-yl(3S,3aR,6R,6aR)-6-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluoroctanoyl oxy)hexahydrofuro[3,2-b]furan-3-yl adipate(M7). Meanwhile the three series of polymers P1-P3and all monomers except M1, were no reports at home and abroad.FT-IR spectroscopy, differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) were used to investigate the structures and properties of the products.The results show that:the chemical structure of the synthesized monomers and polymers are consistent with the molecular designs, M1was cholesteric liquid crystal, fluorinated monomer M2was nematic liquid crystal. Fluorinated monomers M3M4and M5are cholesteric liquid crystal. Fluorinated monomers M6and M7are Chiral liquid crystal. Three series of polymers P1～P3were all cholesteric liquid crystals and exhibited colorful cholesteric Grand-jean textures on both heating process and cooling cycle. With the increasing the content of M3, Tg of series of P1decreased, while Ti of P1decreased firstly, and then increased; With the increasing the content of M4, Tg and while Ti of series of P2increased; With the increasing the content of M5, Tm of series of P3decreased firstly, and then increased, while Ti of series of P3increased. Three series of polymers P1～P3were all optical active, and all of them had good thermal stability.