Nanostructures obtained in the oxidative polymerization of aniline: Effects of polarons

Effects of polarons on the single (NH4OH) and double (NH4OH + LiOH) dedoped nanostructured products obtained in the oxidative polymerization of aniline are investigated. These effects are probed by 15N and 13C solid-state NMR, FTIR, Raman and EPR spectroscopy. The morphologies were imaged using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The micrographs confirmed the presence of mixed morphologies which include granular and nanotubular products. Single dedoping with NH4OH (SD) was not sufficient to completely remove positive charges. Subsequent dedoping with LiOH (DD) significantly removed positive charges. NMR experiments confirmed that the imine part of the structure has been more exposed to the effects of polarons. EPR data showed that the spin concentration in the DD samples was more than an order of magnitude lower that of the SD sample. The FTIR and Raman spectra exhibit characteristic bands for polyaniline and oligoanilines.