Synthesis of Self-Doped Conductive Poly(3,4-ethylenedioxythiophene) (PEDOT) Bearing Phosphonic Acid Moieties

The synthesis of self-doped conductive poly(3,4-ethylenedioxythiophene) (PEDOT) bearing phosphonic acid moieties is first reported. The UV-vis-NIR spectrum of the film clearly confirmed self-doping. The polymer exhibited good water solubility as a salt with NMe3, as demonstrated by filtration tests with a membrane filter (0.02 µm). This result is in contrast to a PEDOT/poly(4-styrene sulfonate) dispersion, which cannot pass through the filter. The conductivity of a drop-cast film reached 1.3 × 102 S cm−1. The thermogravimetric analysis and elementary analysis of the drop-cast film showed that the conductive polymer presents as a NMe3 salt, which might protect the materials from acid-induced corrosion. The developed conductive polymer has the potential for being applied in various organic electronic materials.