Directional polymerisation and electronic properties of a cyanosubstituted dialkylpolyphenylenevinylene

The synthesis of a monomer allowing for directional polymerisation based on the Knoevenagel condensation reaction is presented. The free running polymerisation gave a molecular weight (Mw = 24650 g mol-1) polymer product. The polymerisation reaction could be followed by size exclusion chromatography (SEC) and the molecular weight of the polymer product could be controlled by termination of the polymerisation reaction at a suitable time.

When terminated before completion a lower molecular weight product was obtained that could be separated into oligomers using preparative SEC. The polymer product and the oligomers were found to have very similar physical properties in terms of the optical band gaps, electronic energy levels and charge carrier mobilities as studied by UV-vis and pulse radiolysis time resolved microwave conductivity (PR-TRMC).

Finally the positions of the filled energy levels were determined using ultraviolet photoelectron spectroscopy (UPS).