Synthesis And Properties Of PPVs Derivatives Electroluminescent Polymers

Polyphenylene vinylene (PPV) is an important kind of electroluminescent polymers. It has many advantages over others, such as high luminescence, good stability in air and fine mechanical strength, but it remains the poor processability and gives off blue-light with much difficulty. It can't solve in organic solvents and decompose before melting. It was discussed in the paper the basic electroluminescent theory of polymers as well as the current study and the development trend of electroluminescent polymers and, especially that of polyphenylene vinylene. On this basis, the relationship among structure, solubility and electroluminescent properties was studied.In this paper, PPVs derivatives with alkoxyl as side-chain and PPVs derivatives containing oxadizole were synthesized; the monomers and polymers were characterized as well. It was studied systemically the influence of component and molecular structure of main-chain and side-chain or side-groups on polymer solubility, electroluminescent and photoluminescent properties, thermostability, and light-emission device performance.1.Syntheses of PPVs derivatives with alkoxyl as side-chain by the method of dehalogenating condensation reactionThose PPV derivatives, named poly (2-methoxy-5-alkoxyl) phenylene vinylene,containing alkoxyl(RO) on benzene ring, were placed on emphasis in this paper. The results indicate that the introduction of alkoxy can greatly enhance the solubility of PPV in common organic solvents like THF, methylene chloride and so on. The improvement of PPV's solubility results from the free-rotation of C-O bond and space-effect of alkoxy-groups. Substitutes make the conjugation plane twist and the flexibility of main chain forwards; the interaction of polymeric segment-solvent and of segment-segment enhances. Under the influence of alkoxy group, the peak value of electroluminescence and potoluminescence exhibits red-shift from 430nm to 480 nm, but the blocked PPV exhibit blue-shift.2.Syntheses of PPVs derivatives containing oxadizole by Heck reactionChromophore of oxadizole was introduced into the chain of PPVs derivatives with alkoxyl as side-chain by Heck reaction. These polymers have good solubility in common organic solvents like THF, methylene chloride and so on. They also have a beneficial...