POLYANILINE MICRORODS

Polyaniline (PANI) prepared in water or a water-methanol (1:1) mixed s olvent by anodic oxidation of aniline hydrochloride at a potential of 0.8 V (and higher) vs. Ag/AgCl appears to form microrods of almost uni form shape and dimensions: a diameter of 0.7 mu m and a length of 2-3 mu m or more, A surface point contact Pt or Ir electrode has been used as the working electrode to get a better ordering in the product due to the surface tension effect, The structure observed with a scanning electron microscope (SEM) is complex: the sample is highly porous and looks like a coral reef; the average channel diameter is 1.5 and 2.5 m u m for narrow and wide channels respectively, The rods appearing in g reat number in the sample are surprisingly uniform, particularly with respect to the diameter, The electrical conductivity is of the order o f 10(-1) S cm(-1) for most samples examined, The electron spin resonan ce (ESR) spectra consist of a strong singlet line (g=2.0030-2.0039, De lta H=0.12-0.50 mT); similarly, the infrared (IR) spectra show a stron g and broad absorption due to electron excitations and electron-lattic e interactions, which we have observed previously for many PANI sample s examined in our laboratory. (C) 1997 by John Wiley & Sons, Ltd.