Self-assembled conducting polypyrrole micro/nanotubes

Abstract

Self-assembled polypyrrole (PPy) micro/nanotubes, whose diameters and room temperature conductivities were within the ranges of 50–2000 nm and 2–40 S cm−1 respectively, were successfully synthesized by a chemical and electrochemical method in the presence of β-naphthalene sulfonic acid or p-toluenesulfonate acid as the dopant. By changing the polymerization method and conditions as well as dopant structures, one can control the morphology, size and electrical properties of the doped PPy. It was proposed that dopant micelles or pyrrole/dopant clusters act as templates in the formation of the micro/nanotubes.

One‐Dimensional Conducting Polymer Nanostructures: Bulk Synthesis and Applications

“…These reaction conditions are similar to conditions employed by Wan et al [63][64][65][66][67][68][69][70][71] to produce PAni nanotubes in their ''template-free'' method, i.e., in both cases, aniline is polymerized under high pH conditions. The mechanisms proposed by both groups are similar in the sense that a suitable template formed in situ serves as a scaffold to dictate nanotube formation.…”

“…As noted, the mechanism of the formation of anisotropic PAni nanostructures under these specific conditions is still unclear. An alternative theory to the one proposed by Wan et al [63][64][65][66][67][68][69][70][71] has recently been suggested by Stejkal et al [97][98][99][100][101] as discussed in the following section.…”

“…This technique has been referred to as a ''template-free'' or ''self-assembly'' approach because the synthesis does not entail the use of an insoluble hard-template. [63][64][65][66][67][68][69][70][71] As noted previously, we classify this approach in this particular section based on the author's own proposed mechanism, which involves the self-assembly of dopant molecules (molecules that are not inherent to the polymer chain) in order to produce anisotropic conducting polymer nanostructures. The unique aspect of this approach, compared to other soft-template techniques, is that the functional dopant does not necessarily need to be removed from the polymer.…”

“…Since conducting polymers require dopants in order to achieve high electrical conductivity, these dopants do not necessarily need to be removed. This general concept, pioneered by Wan et al, [63][64][65][66][67][68][69][70][71] has been used to synthesize PAni nanofibers and nanotubes using a variety of different functional dopants. For example, when aniline is polymerized in the presence of b-naphthalene sulfonic acid, PAni nanotubes and nanofibers with tunable diameters ranging from 76 to 650 nm are obtained depending on the acid to monomer ratio.…”

Facile Synthesis of Polyaniline‐Polypyrrole Nanofibers for Application in Chemical Deposition of Metal Nanoparticles

“…[20] In contrast, the bands between 800-790 cm À1 (the C-H out-of-plane ring deformation vibration), at about 1 490 cm À1 (the C --C stretching modes of the benzenoid ring) and at about 1 295 cm À1 (the C-N stretching modes of the leucoemeraldine) became weaker with increasing the dosage of Py monomer during the polymerization process. Surprisingly, the C-H in-plane bending mode of permigraniline at 1 140 cm À1 was discovered only for the nanofibers from [An:Py] ¼ 9:1, 3:1 and 1:1, [21,22] and completely disappeared in the other two PANI-PPy nanofibers. The conductivities of the PANIPPy nanofibers (10 À2 -10 À3 S Á cm…”