Patterning of Polymers on a Substrate via Ink-Jet Printing of a Coordination Polymerization Catalyst

The generation of laterally structured patterns of conju gated, conductive polymers on flat substrates is a key step in the development of new technologies for the production of, for example, displays or low cost flexible circuits. Printing and related procedures, in which the pattern of the individual pieces produced can also differ from one another, are patterning techniques suited for mass production and they are versatile with regard to the substrate. However, when using polymers they are often hampered by limited solubility and the high viscosity of polymer solutions. This applies particularly to conjugated polymers, patterning of which, however, is of particular interest owing to their conductive and electro optical properties. The direct patterning on a surface of a small amount of an appropriate compound, which promotes polymerization of subsequently added monomer, is an attractive approach to the aforementioned issue in principle. Patterning of a transi tion metal coordination polymerization catalyst would be particularly attractive, as in catalytic polymerization one active site may form more than one polymer chain, and catalytic polymerization enables microstructure control. We report herein on the patterning of polymers via ink jet printing of a coordination polymerization catalyst. We chose polyacetylene as an example, as it is the prototype of a conjugated, conductive polymer and at the same time it is unprocessable from the neat bulk polymer owing to its insolubility and intractability. A prerequisite for this approach are suitable polymerization catalysts that tolerate the polar functional groups ubiquitous on most substrates. For example, paper or glass surfaces contain OH groups and adsorbed water. In general, late transition metal catalysts are more tolerant towards polar groups than the more oxophilic early transition metal catalysts, as illustrated by their capability to co polymerize olefins with polar substituted monomers and to polymerize in aqueous emulsion.