Side-chain Chiral Azo Liquid Crystal Polymer Synthesis And Optical Response

In chapter 1, summarize is provided on the study of chiral liquid crystalline polymers (LCP) containing azobenzene chromophores in the side chain. Here, a lot of conception and properties have been discussed, such as the conception of chiral LCP and azobenzene-containing polymer, the properties and application of chiral azo LCPs, the relationship between the properties and the molecular structures of chiral azo LCPs. The design and synthesis of chiral azo LCPs are discussed. And the progress of chiral azo LCPs is expatiated in detail. Chiral azo LCPs, a kind of polymers with chiral carbon atoms (C*) and azobenzene chromophores in their structures, not only exhibit special liquid crystalline properties, but also exhibit special optical properties for application in optical devices and display. Thus, the synthesis and optically active properties of chiral azo LCPs have recently attracted considerable interest in the field of chiral azo liquid crystalline polymers.In chapter 2, a series of optically active polymethacrylates containing azobenzene chromophores and chiral groups with different spacer length, PMxAP (x=0,2,6,11), were synthesized and characterized. Effect of spacer length on the chiroptical properties of the synthetic polymers has been investigated by circular dichroism (CD). Before irradiation with LPL, CD spectra were observed for all the monomers (MxAP (x=0,2,6,11)) in solid state. However, CD spectra were observed only for films of PMxAP (x=6,11), but not for films of PMxAP (x=0,2), this indicated that the spacer length has effect on the chiroptical properties of the polymers. After irradiation with LPL at 442 nm, CD spectra were observed for all the polymers in films. Compared with native films of polymers (PMxAP (x=0,2,6,11)), CD values were amplified for all the irradiated polymeric films, which indicated that more helical arrangements were induced in all the irradiated polymeric films than those in the native polymeric films. Results of CD spectra of the polymeric films show that the highestphotoinduced amplification of chirality, concerned to the most efficient absorption (Ï€...