Preparation and characterization of trifluoromethylaniline oligomers

The oxidation of m-trifluoromethylaniline in the presence of trifluoroacetic acid leads to the preparation of poly(m-trifluoromethylaniline). The dimer and a mixture of higher oligomers have been prepared using both cyclic voltammetry for the preparation of thin films, and controlled potential electrooxidation for the preparation of powders. The CF₃ moiety attached to the backbone shifts the oxidation potential of the thin film toward more positive potentials as might be expected because of the electron-withdrawing effects of the CF₃ group. The conductivity of the film has been estimated to be on the order of 10⁻⁸ S/cm when electrooxidized under the appropriate conditions of pH and potential. Extensive analysis of the products of electrooxidation indicates that the solution consists of oxidized monomer, while the dimer and higher molecular weight oligomers precipitate. The dimer can be separated from the other oligomers by vacuum sublimation. Gel permeation chromatography of the remaining precipitate indicates that the precipitate consists of 20% trimer and tetramer, 40% pentamer and hexamer, and about 40% higher molecular weight oligomers.