Study on the formation of a supramolecular conjugated graft copolymer in solution

The formation in solution of a supramolecular graft copolymer bearing conjugated blocks is demonstrated using diffusion ordered NMR spectroscopy (DOSY). A tailor-made poly(3-(2-ethylhexyl)thiophene) (P3EHT) with a phenol end group is synthesized. For this purpose, the chain-growth mechanism of the polymerization of 2-bromo-5-chloromagnesio-3-alkylthiophenes in the presence of a Ni(dppp) catalyst (dppp = 1,3-bis(triphenylphosphino)propane) is exploited, as it enables the use of functionalized initiators to introduce specific end groups. The so-obtained polythiophene was subsequently mixed in solution with poly(4-vinylpyridine) (P4VP) to enable phenol-pyridine hydrogen bonding. The formation of the supramolecular graft copolymer is studied using DOSY-measurements. Based on the results thereof, the amount of P3EHT attached to the P4VP is calculated and the association constant of the hydrogen bond is estimated.