Facile Synthesis of ABA Triblock Copolymer Containing Regioregular Poly(3-hexylthiophene) and Polystyrene Segments via Linking Reaction of Poly(styryl)lithium

The facile synthesis of a coil-rod-coil ABA triblock copolymer containing regioregular P3HT and PS segments (PS-b-P3HT-b-PS) based on a novel approach involving two steps, was reported. The polymerization of 2-bromo-5-chloromagnesio-3-hexylthiophene initiated with Ni(dppp) Cl2 was carried out by the quasi-living GRIM method. The intermediate P3HT complex was reacted in situ with the Grignard reagent, 1-[4-(3-bromomagnesiopropyl)-phenyl]-1-phenylethylene, in THF at room temperature for 30 minutes. The excess homo PS was successfully eliminated by fractional precipitation using cyclohexane/hexane. H NMR spectroscopy of PS-b-P3HT-b-PS confirms the absence of the signal for the vinyl protons of DPE moieties at 5:43 ppm as well as a reasonable composition of two segments being almost consistent with that targeted S1b. The thermal property of the polymer was investigated by differential scanning calorimetry, exhibiting Tg at 95°C and Tm at 208°C.