Synthesis, characterization, and solution structure of all-conjugated polyelectrolyte diblock copoly(3-hexylthiophene)s

Abstract

We report on a new class of all-conjugated polyelectrolyte diblock copoly(3-hexylthiophene)s, poly(3-hexylthiophene)-b-poly[3-[6-(N-methylimidazolium)hexyl]thiophene] (P3HT-b-P3MHT). The polyelectrolyte diblock copolymers were prepared by a catalyst-transfer Kumada polycondensation followed by quaternization of the bromohexyl side groups of the poly[3-(6-bromohexyl)thiophene] block with N-methylimidazole. The obtained diblock copolymers have well-defined block ratios, narrow polydispersity indices, and high regioregularity. Their characterization as well as the thermal, crystalline, and optical properties, and self-assembly behavior have been investigated in detail. Transmission electron microscopy (TEM) provided evidence for solvent-induced self-assembly. A series of morphologies including short or long nanowires and nanorings could be obtained depending on the selectivity of solvents toward different blocks and the block ratios.