Structure of Ultralong Polyaniline Nanofibers Using Initiators

Detailed morphological and structural characterization of high-aspect-ratio polyaniline nanofibers obtained using a small amount of p -aminodiphenylamine (dimer) or p -phenylenediamine (diamine monomer) as an initiator into a rapidly mixed reaction is presented. Structural characteristics have been investigated by FT-IR, UV−vis−NIR, solid-state 13 C NMR, and 15 N NMR, while the morphology was examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Nanofibers obtained with the addition of an initiator appear longer and less entangled than those obtained without any initiators. TEM analysis revealed a distinct morphological difference between the nanofibers synthesized with different additives. The p -aminodiphenylamine-initiated polyaniline possesses an electrical conductivity of 3.0 S cm −1, while the p -phenylenediamine-initiated counterpart has a conductivity of 1.7 S cm −1 . FT-IR, 1 H− 13 C cross-polarization (CP), 15 N direct polarization (DP), and UV−vis−NIR spectroscopy confirm that a regular polyaniline structure prevails in both nanofibers. Therefore, various initiators only result in a slight difference in the final polymer molecular structure and physical properties, but such minor divergence dictates the subsequent chain assembly and affects the supramolecular morphology significantly.