Polyurethanes, derived from the comonomers, methylenebis(4-phenylene isocyanate), 1,4-toluenediyl diisocyanate, and 1,6-hexamethylene diisocyanate, have been synthesized that contain the tetracyanoquinodimethane group in the polymer backbone. The electrochemistry of these materials has been examined in N,N-dimethylacetamide solution and as thin films in contact with either aqueous or nonaqueous electrolyte solutions. In solution successive electron-transfer steps are observed for the formation of noninteracting radical anion and dianion sites on the polymer chain. As thin films on conducting substrates the behavior varies from partial to full electroactivity depending on the solvent and the polymer structure. In contact with 0.1 M LiCl/H2O, films of the aromatic polyurethanes are only partially reduced to the radical anion state on the voltammetric time scale, while full electroactivity is seen in acetone solvent. For all the materials, charge transport through the films via the anion/dianion oxidation states is a sensitive function of the solvent, swelling, and flexibility of the polymer chain backbone.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry