SEM study of the morphology of high molecular weight polyaniline

High molecular weight polyaniline (PANI) was synthesized by adding neutral salt technique with MacDiarmid's method and the morphology of the obtained PANI was examined by the scanning electron microscope (SEM). A remarkable and special phenomenon has been found that the SEM images of resulting PANI show a mass of clews, the average diameter of which is about one micrometer. Furthermore, these honeycombed clews are tenuous, interconnected fibrillar network with characteristic cross-sectional fibril dimensions of a few tens of nanometers. In addition, various preparation parameters which will probably influence the morphology of the high molecular weight PANI in our investigation are: (a) the concentration of lithium chloride ([LiCl]); (b) reaction temperature (t); (c) molar ratio of aniline:oxidant ([An]/[APS]); (d) the concentration of aniline ([An]); (e) the concentration of hydrochloric acid ([HCl]). Some correlations between the sample preparation process and its morphology properties have been obtained.