Anionic PPV polymerization from the sulfinyl precursor route: Block copolymer formation from sequential addition of monomers

The sulfinyl precursor route for the synthesis of poly(p-phenylene vinylene) (PPV) materials via an anionic polymerization procedure employing dedicated initiators is evaluated in depth. Reaction kinetics are investigated to gain more control over the polymerization, since polymerization proceeds to full conversion already on the timescale of mixing of the reaction components. Even at -78 °C almost full conversion of the monomer is observed after few seconds. BEH-PPVs are obtained in the range of 3000 to 16,000 g mol ^-1, whereby dispersity decreases with decreasing molecular weight, allowing for materials with a PDI of 1.1 for the smallest PPV chain. Block copolymerizations were performed via sequential addition of monomers to make use of the living PPV chain ends. Bimodal product mixtures are obtained, consisting of block copolymer as well as PPV homopolymer. The block copolymer PPV-b-poly(tert-butyl acrylate) could nevertheless be separated by selective precipitation as well as preparative chromatography techniques.