Solution processible and conductive polyaniline via protonation with 4,4-bis(4-hydroxy phenyl)-valeric acid: Preparation and characterization

It is demonstrated that polyaniline salt, obtained by simple protonation of its base form with 4,4-bis(4-hydroxy phenyl)-valeric acid (HPVA), combines solution processibility with electrical conductivity. The solution of PANI–HPVA in DMF and m-cresol mixture has been characterized by UV–vis spectroscopy, exhibiting spectral features characteristic of the protonated state. Precipitation of dissolved PANI–HPVA with chloroform, leads to powder of spherical morphology with an average particle size of 400 nm which is amorphous by X-ray. Their conductivity is ca. 10− 3 S/cm (measured for pressed pellets). Thermogravimetric investigations indicate good thermal stability of this novel form of polyaniline, however some weight loss is observed below 200 °C, associated with the removal of minute amounts of solvent entrapped within PANI–HPVA grains in the precipitation process. PANI–HPVA has film forming properties and free standing films (conductivity ca. 10− 4 S/cm) can be obtained by dissolving the powders in DMF, followed by casting.