Synthesis And Characterization Of Acrylate Liquid Crystalline Compounds Containing Steroid Groups

In recent years,chiral liquid crystalline polymers(LCPs)have attracted more and more attention due to their unique optical-electrical property and the potential application in the fields of nonlinear optics,fast light switch,microelectronics.The synthesis of chiral LC materials with new structure has been a very important subject in LC research.As functional LC groups,cholesterol and diosgenin have multiple chiral centers.However,few studies have been reported on the design and synthesis of functional acrylate LC materials containing diosgenyl group.Herein,a novel class of functional acrylate LC monomers based on cholesterol and diosgenin were designed and synthesized,and lay a foundation for acrylate chiral LCPs.In the second chapter,four new cholesteryl derivatives bearing primary hydroxyl groups were synthesized and named as 2-cholesteroxyethanol(C1),4-cholesteroxybutane-l-ol(C2),6-cholesterhexane-1-ol(C3),and 8-cholesteroxyoctane-1-ol(C4).Then,four LC monomers were synthetized by reacting four intermediate compounds with acrylic acid,they were 2-cholesteroxyethyl acrylate(M1),4-cholesteroxybutyl acrylate(M2),6-cholesteroxyhexyl acrylate(M3),and 8-cholesteroxyoctyl acrylate(M4).The structure of all the intermediates and monomers were characterized by FT-IR,and their optical textures and thermal properties were characterized by means of polarizing optical microscopy(POM)and differential scanning calorimetry(DSC),respectively.The influence of the length of the methylene was also studied.DSC results indicated that the melting temperature and isotropic temperature of the four intermediate compounds(C1-C4)and monomers(M1-M4)decreased with increasing length of methylene,however,the mesophase temperature range of intermediate compounds widened except for C1.POM results showed that C1 exhibited fan-shaped texture of smectic phase,C2-C4 showed fan-shaped texture of smectic phase and focal conic and oily streak textures of cholesteric phase during heating and cooling process.Four monomers all showed focal conic texture of cholesteric phase during heating and cooling process.In the third chapter,four new diosgenyl derivatives bearing primary hydroxyl groups were synthesized and named as 2-diosgenoxyethanol(C5),4-diosgenoxybutane-1-ol(C6),6-diosgenoxyhexane-1-ol(C7),8-diosgenoxyoctane-1-ol(C8).Then,four LC monomers were synthetized by reacting four intermediate compounds with acrylic acid,they were 2-diosgenoxyethyl acrylate(M5),4-diosgenoxybutyl acrylate(M6),6-diosgenoxyhexyl acrylate(M7),8-diosgenoxyoctyl acrylate(M8).The structure of all the intermediates and monomers were characterized by FT-IR,and their optical textures and thermal properties were characterized by means of polarizing optical microscopy(POM)and differential scanning calorimetry(DSC),respectively.DSC results showed that the melting and isotropic temperatures of C5-C8 decreased with increasing length of methylene,and the isotropic temperatures of M5-M8 didn't have a noticeable trend.POM results showed that C5-C8 exhibited fan-shaped texture of smectic phase and M5-M8 exhibited focal conic textures of cholesteric phase during heating and cooling process.