The Synthesis And Properties Of Poly (5,8-Quinolinene Vinylene)

Extensive studies have been made on organic and polymeric light emitting diodes (LEDs) because of their practical application as well as inherent scientific interest. Polymer LEDs using Poly (p-Phenylene Vinylene)(PPV) were first reported in 1990 by Friend Research group and since then various other kinds of conjugated polymers have been developed which exhibit electroluminescence. However, it is seldom reported that PPV and its derivatives are applied to the research of the electrorheological property.The electrorheological fluid is a novel type of functional material, which is usually made up of dispersing medium with the non-conductor and dispersed phase particles with the higher dielectric constant. At the end of the eighties of the 20th century, Block and Kelly reported that ER fluids made by using some organic macromolecular compounds such as poly(pyrene-quinone), poly(naphthalene- quinine), etc. as dispersed phase particles may do not at all contain water and have a wider working temperature. Therefore, extensive attention has been caught to organic polymer dispersed phase particles. But so far, electrorheological fluid has some scarcities, such as not high enough yield stress, not wide enough working temperature range, and not good enough anti-subside ability.According to the suitable range of dielectric constant, moderate density and hardness of PPV polymers, allowing for the quinoline`s conjugated structure of theπ-bond, we select quinoline as the basic unit to synthesize Poly (5,8-Quinolinene Vinylene) (PQV) and studied its photoluminescence and the electrorheological property.We have designed and synthesized a novel linear conjugated polymer. PQV was obtained via sequentially nitration, reduction, cyclization, bromination and condensation from p-xylene. And the experimental condition was optimized. The structure of PQV was characterized with IR, elemental analysis and ultra-visible spectrum, etc. The surface morphology of the polmer was measured with a scanning electron microscope. Thermal stability of the polymer was measured with thermal analyzer. And the molecular of PQV was calculated according to the characterization that PQV, which was got in Gilch Reaction, must end in bromomethyl. Results show the synthesized polymer is in well agreement with the design requirement. The PQV-silicon oil suspension with 10wt % was prepared by dispersing PQV in silicon oil and the electrorheological properties were measured. The relationships among the yield stress, shear stress, shear rate, apparent viscosity and electric field were thoroughly studied. Results show that the suspension of 10wt % PQV-silicon oil presented electrorheological effect, yield stress was in proportion to electric field. The apparent viscosity of the ER fluid presented obvious shear-thinning effect, and showed linear relationship with the electric field.In the paper, the photoluminescence (PL) properties of PQV were studied primarily. The results show that the maximum emission of PL spectrum of the solid sample took place at 647nm. And theπ-π* band-gap was calculated by ultra-visible spectrum and cyclic voltammetry to be 3.7 eV and 3.08 eV respectively.