Well-Controlled Synthesis of Block Copolythiophenes

Well-controlled rod−rod block copolymers, poly(3-hexylthiophene)-b-poly(3-phenoxymethylthiophene)s, were successfully prepared by nickel-catalyzed coupling polymerization of 2-bromo-3-hexyl-5-iodothiophene followed by that of 2,5-dibromo-3-phenoxymethylthiophene. The homopolymerization of 2,5-dibromo-3-phenoxymethylthiophene was investigated in detail to determine the polymerization conditions. The structure of block copolymers was confirmed by FT-IR and 1H NMR spectroscopies, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), ultraviolet−visible (UV−vis), and fluorescence spectroscopies. The thin film formed on a silicon wafer and annealed at 40 °C for 3 days was analyzed using atomic force microscopy (AFM), and the results indicated the existence of phase separation.