Dependence of the luminescent properties and chain length of poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] on the formation of cis-vinylene bonds during Gilch polymerization

作者：Fan YL; Lin KF^*

来源：Journal of Polymer Science Part A: Polymer Chemistry , 2005, 43(12): 2520-2526.

DOI：10.1002/pola.20717

• conjugated polymers
• light-emitting diodes (LED)
• luminescence
• poly[2methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV)

The presence of cis-vinylene bonds in Gilch-polymerized poly[2-methoxy-5(2 '-ethyl-hexyloxy)-1,4-phenylene vinylene] is reported. Through fractionation, species with a weight-average molecular weight of less than 37,000 exhibited an abnormal blueshift of photoluminescence spectra in toluene solutions, and this was attributed to the presence of cis-vinylene bonds, as verified by NMR spectroscopy. Surprisingly, the fractionated species (similar to 1 wt %) with a weight-average molecular weight of 5000 were mostly linked by the cis-vinylene bonds. The concentration decreased with the molecular weight until a molecular weight of 37,000 was reached; at that point, the polymer chains contained mainly trans-vinylene bonds. Obviously, the formation of cis-vinylene bonds strongly inhibited the growth of polymer chains during Gilch polymerization.

• 出版日期2005-6-15