Preparation and thermotropic liquid crystalline properties of semirigid copolyurethanes composed of biphenyl units and partially fluorinated aliphatic chains

Synthesis and properties of new liquid crystalline polyurethanes containing mesogenic side chain

“…Because of the strong intermolecular interaction arising from hydrogen bonding of the urethane linkage, the synthesis of TLCPUs seems more difficult than the synthesis of the other liquid crystalline polymers. However, there were mainly three methods for preparing TLCPUs: (i) using interfacial polymerization of secondary amines with dichloroformates [13], (ii) by melt polycondensation of diols with alkylene diphenyl dicarbamates [14], and (iii) by polyaddition of diols with diisocyanates. Conventionally, TLCPUs have been prepared by polymerization of mesogen-containing monomers, i.e.…”

Perfluorocyclobutyl Liquid Crystalline Fluoropolymers. Synthesis and Thermal Cyclopolymerization of Bis(trifluorovinyloxy)-α-methylstilbene

“…The typically well-defined polymer chemistry and range of controlled properties offered by TFVE cyclopolymerization prompted us to pursue the synthesis of liquid crystalline (LC) fluoropolymers based on a new TFVE monomer containing the α-methylstilbene linkage. The mesogenic behavior of α-methylstilbene has been studied in a variety of polymer architectures where most recent attention has been devoted to LC epoxy thermosets. − Semifluorinated liquid crystalline compounds consisting of small molecules as well as side chain LC polymers − are also known. The incorporation of low surface energy electronegative fluorocarbon groups in liquid crystals may impart a large influence on a combination of properties such as the bulk permittivity and surface organization in film and coating applications. , Here we report the synthesis and characterization of the first liquid crystalline polymer containing the PFCB linkage and our initial efforts in probing the anisotropy as a function of semifluorinated step-growth polymer dimensions.…”