Characterization of Polyaniline Nanotubes Formed in the Presence of Amino Acids

Abstract

Self‐assembled nanotubular structures of polyaniline were chemically synthesized from solutions containing different amino acids with the addition of ammonium persulfate as the oxidant. The materials were characterized by SEM and a range of spectroscopic methods. Spectroscopic characterizations revealed that the synthesized materials had many features typical of chemically synthesized PANI. Some additional features were also found and have been ascribed to non‐conducting material formed in the initial stages of the reaction at a higher solution pH. However, UV‐vis and 13C NMR spectra point toward a conductive material as the final product of the reaction. Cyclic voltammetry results also indicate an electroactive final product that closely resembles regular PANI in its electrochemical characteristics.magnified image

Polyaniline: The infrared spectroscopy of conducting polymer nanotubes (IUPAC Technical Report)

“…The difficulty of determining the presence of specific complex organic structures from bands in the infrared spectra is due to the fact that they do not correspond to characteristic group frequencies. FTIR spectroscopy alone is not able to provide definite answers on the details of molecular structure [13,18,19]. Additional and complementary methods are thus needed to elucidate the molecular structures related to the formation of the PANI nanotubes.…”

Self-assembly of nanostructures obtained in a microwave-assisted oxidative polymerization of aniline

“…The experimental parameters were set up as previously described [38,40]. An external cooling circuit maintained constant temperature of the reaction mixture and constant irradiation power.…”

“…[35]. We have previously reported studies of the selfassembly of various nanostructures synthesized at relatively low temperatures and at initial medium pH based on a conventional aniline oxidative polymerization approach [18][19][20][21][38][39][40][41]. However, using microwave synthesis at low pH PANI was produced in 5 minutes with 80% yield (synthesized sixty times faster compared to the classical chemical synthesis).…”

A Template‐Free Method toward Urchin‐Like Polyaniline Microspheres

“…The peak at 286 nm is attributed to the p-p à benzenoid transition, while the peaks at 435 and 839 nm are related to the partial protonation and polaron transition of the PANI chains. [16] The results indicate that the urchin-like PANI microspheres are in the conductive emeraldine salt form. The room-temperature conductivity of the urchin-like PANI pellet, measured by a four-probe method, is about 6.5  10 À2 S Á cm…”

“…[12][13][14][15][16][17] By changing these polymerization parameters, various PANI micro/nanostructures from one dimensional (1D) to three dimensional (3D), such as nanotubes, nanofibers, nanosheets, and hollow spheres, have been successfully synthesized with template-free methods. [16,[18][19][20][21] It is believed that the multidimensional assembly of nano-units has a marvellous ability to control the physical and chemical properties of materials because of their novel architectures. [21,22] Urchin-like PANI microspheres with an average diameter of 5-10 mm have been successfully prepared.…”