Study On The Synthesis And Properties Of Helical Polyacetylene Carrying Azo Electro-optic Chromophore

Azobenzene is a well-known photo responsive chromophore that undergoes reversible photoisomerization between trans and cis forms. Polymers carrying azobenzene moieties have attracted much attention due to their unique properties, which allow various photonic applications such as holographic and digital storage of information. There have been many reports concerning polymers carrying azobenzene moieties displaying photoresponsive, photoswitchable, optical memories, and liquid crystalline properties.On the other hand, substituted polyacetylenes possess alternating double bonds in the main chain, which endows them with unique properties such as semiconductivity, high gas permeability, nonlinear optical properties, formation of ferroelectric liquid crystals, and helical structures.Some polyacetylenes substituted with chiral side chains exhibit strong circular dichroism (CD) signals and large optical rotations based on the helical conformation, It is expected that azobenzene-containing helical polyacetylenes will combine these characteristics together and lead to the development of new functional materials, Such polyacetylene material will show a series of special optical activity of liquid crystal, molecular recognition and so on.The thesis consists of four chapters:Chapter One reviews the structural characteristics, the various preparation methods, application prospects about helical polyacetylenes and the liquid crystal polymers containing azo in side-chain, especially the research of application at non-linear optical materials and liquid crystal materials was introduced.The content and feature of the thesis were pointed out.Chapter two reported seven novel Y-containing azobenzene chromophore side alkynyl monomers (M1-M7). The synthetic route is carried out by esterification, diazotization coupling, amidation and a series of reaction steps. The monomer structure was characterized by IR, NMR, UV, etc.. The seven creative monomer's difference was realized by changing the Functional group of Y-type molecular, By comparing them, we can understand how the structure affects the properties of them. In the molecular structure, we introduce chiral molecules L-alanine, and use the introduction of amide groups to get hydrogen bond, Lay the foundation for further study of that by contrast with and without hydrogen bonds and by whether they contain chiral structure to study their effects on property of their polymer.Chapter three reported that a series of propargyl derivatives monomer was polymerized by [Rh(nbd)Cl]2 and Et3N catalyst System. This catalyst system has a good effect to keep main chain cis-trans conformation. IR, NMR, UV, circular dichroism spectroscopy, thermogravimetry, differential scanning calorimetry, GPC were used to investigate the nature of this series of polyacetylene, and also the impact of structure to the poylmers were stuied.Chapter four gave a simple conclusion of the thesis, and the subject's research content in aftertime and the outlook of future research were reviewed.