Liquid Crystals and Ordered Polymers for Infrared and Microwave Applications

摘要

1. A large number of new liquid crystals were synthesized for possible applications in advanced electro-optic devices operating in infrared and microwave ranges. These compounds contain an electron-donating group and an electron-accepting group separated by a conjugated mesogenic core. The 'push- pull' structure imparts a large longitudinal dipole moment on the molecule, resulting in very large dielectric anisotropy and significant birefringence extending to the infrared region. The electro-optic properties of several of these compounds dissolved in room-temperature nematic solvents have been measured. (2) Macroscopically oriented epoxy thermosets were formed by polymerizing liquid crystalline diepoxides with an aromatic diamine. They show increased mechanical strength over unoriented samples, and possess optical anisotropy. (3) Two short projects not originally planned were also carried out. The first was the production of super-strong cellulose aerogels, and the second was an NMR study of a polymer-dispersed liquid crystal (PDLC) system.