Synthesis and Properties of Optically Active Polyaniline Carbon Nanotube Composites

Abstract

The in-situ polymerization of aniline in the presence of multiwalled carbon nanotubes and (S)-(+)-10-camphorsulfonic acid provides a route to optically active composite materials. Their chiroptical properties suggest that polymers and composite materials adopt similar optical properties indicative of “compact coil” in DMSO and “extended coil” in m-cresol. The optical activity in composite materials is preserved, although somewhat reduced to that of the pure polymer, which is attributed to the polymer phase coating nanotubes. This polymer phase is responsible for the lower electrical resistance observed for composite materials.

Polyaniline-carbon nanotube composites

“…The ES form of PANI shows crystalline peaks centered at 2θ = 9.4°, 15.3°, 20.7°, 25.2°, 26.5°, and 29.8°cor-responding to (001), (011), (020), (200), (121), and (022) reflections, respectively [35]. The as-prepared sample of MWCNT by chemical vapor deposition shows three peaks at 2θ = 26°, 39.6°, and 43° [46]. However, the acid-treated and -COOH-functionalized sample of MWCNT shows only two diffraction peaks at 2θ = 26°and 46° [35].…”

“…Gupta and Miura have reported that beyond 73 wt % of PANI, the wrapping gets terminated and the PANI is deposited independently around the surface of the composite [62]. Scanning tunneling microscopy (STM) [74], atomic force microscopy (AFM) [75][76][77], and transmission electron microscopy (TEM) techniques [45,46] have been used in morphological characterization, and the results of these studies also reveal a nice encapsulation of CNT by the polymer.…”

“…The composites prepared by in situ polymerization contain all the characteristic peaks of PANI in its ES form. For example, the spectrum shows N-H stretching vibration (3450 cm -1 ), C=C stretching of quinonoid (Q, 1576 cm -1 ) and benzenoid (1493 cm -1 ), C-N stretching mode (1303 cm -1 ), and N=Q=N stretching (1136 cm -1 ) [46]. In addition to the above, the presence of CNT in these composites results in the appearance of a band at 1144 cm -1 whose intensity increases with CNT content [27].…”

“…release of water molecules (<100 °C), dopant anion (180-280°C), and decomposition of PANI (280-630°C) [87]. The decomposition of MWCNT occurs anywhere between 500 and 850°C depending on the method by which it is synthesized [46]. A 1 wt % MWCNT content in PANI-CNT composites extends the onset of decomposition from 280 to 400°C.…”

Preparation, characterization and application of polyaniline nanospheres to biosensing

“…31 The tubular morphology can be explained by the fact that the CSA/anilinium micelle during the polymerization acts as a pseudotemplate for controlled growth of PANI in the form of nanotubes. The crystallite size of the PANI nanotubes and PANI nanospheres is found to be about 45 nm and 71.8 nm as estimated using Scherrer's formula (D ¼ Kl/Bcosq).…”