Synthesis and characterization of poly(4`-(2,2-dialkynyl)ethenylstilbene-4-carboxylate)

Abstract

Chromophoric interactions in conjugated polymers have critical effects on performance of electroluminescence (EL) devices. One of the tactics to control it is to optimize the degree of insulation with alkyl chains. So we suggested a AB2 type hyperbranched copolymer system which have 4-ethenylstilbene as a chromophore for A, and various alkyl chains for B. Via Heck reaction followed by Sonogashira reaction, we successfully synthesized ready-to-polymerize monomer with good yield, and the polymers were obtained through optimized Mitsunobu condensation. Synthesized polymers showed moderate thermal stability up to 300 oC. Compared with monomer, polymer solution in CHCl3 presented same absorption transition. In addition, λabs maxs of polymer films coated on to glass were blue shifted relative to polymer solution, and λems max s of them were red shifted. As varying alkyl chain length from butynyl to undecynyl, fluorescence quantum yields were increased 15-fold.