Chiral nanotubes of polyaniline synthesized by a template-free method

Abstract

Chiral nanotubes of polyaniline (PANI) were successfully synthesized by a template-free method in the presence of (S)-( 2)-2-pyrrolidone-5-carboxylic acid [(S)-PCA)] or (R)-(1)-2-pyrrolidone-5-carboxylic acid [(R)-PCA] as the dopant for the first time. The tubular morphologies of the resulting PANI-(S)-PCA and PANI-(R)-PCA were confirmed by SEM and TEM images. The tubes are 80-220 nm in outer diameter and 50-130 nm in inner diameter. It was proposed that the micelles of aniline-(S)-PCA or (R)-PCA, which were formed due to the hydrophobic aniline and the hydrophilic -COOH group of PCA, played a ''template'' role during the formation of the chiral nanotubes. These chiral nanotubes showed optically active and electrical properties. In particular, a positive and a negative Cotton effect corresponding to a helical screw of the polymer main chains was observed in the chiral nanotubes. The structural characterization measured by FTIR and X-ray diffraction indicated that the configuration of PCA did not affect the main chains of the chiral nanotubes; however, short-range ordering at 2h ~6.43 (d ~13.73 A ˚) was significantly observed from the chiral nanotubes, which might result from the chiral character of the dopant.

Characterization of Polyaniline Nanotubes Formed in the Presence of Amino Acids

“…The sharp peak has been assigned to the periodicity distance between the dopant and N atom on adjacent main chains, while the latter two broad bands have been ascribed to the periodicity parallel and perpendicular to the polymer chains of PANI, respectively. [42,43] There is no obvious difference between the patterns of doped and dedoped PANI which indicates that the dedoping process does not destroy partly crystalline structure of PANI nanotubes, which is in agreement with the results of nanotubes' morphology before and after dedoping.…”

Self‐Assembly of Polyaniline—From Nanotubes to Hollow Microspheres

“…As one can see, one sharp peak at 2h = 6.46 (d = 13.67 ), which can be assigned as the periodic distance between the dopant and N atom on adjacent main chains, [17] is observed for the nanotubes. Similarly, this peak is also observed for PANI-m-HBA (inset, Fig.…”

Preparation, characterization and application of polyaniline nanospheres to biosensing

“…4 emerges due to short range ordering in case of tubular-morphology. 34 Moreover, the diffused circle (marked as 4, Fig. 4 (iii)) infers the absence of ordered-lamellae structure in nanospheres.…”