| Popis: |
A cis-poly(phenylene vinylene) (cis-PPV) recently synthesized by Katayama, Ozawa, and coworkers undergoes photo-isomerization into trans configuration. This isomerization occurred rather quickly within 45 min in solvent-cast films at room temperature. The cis-PPV chains exhibiting this quick isomerization were expected to be highly mobile in the bulk state, and this expectation was examined from thermal, structural, and viscoelastic tests for a cis-PPV sample with Mn=4300 and Mw/Mn=2.16. It turned out that the as-polymerized cis-PPV was partially crystalline and fully melted at Tm≅109 °C. The samples quenched from a molten state to lower temperatures (≤70°C |
