Self‐Assembly of Polyaniline—From Nanotubes to Hollow Microspheres

Abstract

By simply changing the molar ratio of the dopant to monomer, the morphology of salicylic acid (SA)‐doped polyaniline (PANI) can be changed from one‐dimensional nanotubes (∼ 109–150 nm in diameter) to three‐dimensional hollow microspheres (∼ 1.5–3.1 μm in diameter) via a self‐assembly process. Freeze–fracture electron microscopy (FFEM) proved that hollow spherical micelles composed of SA/aniline act as templates in the formation of either nanotubes or hollow spheres. FTIR and X‐ray diffraction measurements suggest that the hydrogen bond of the –OH group of SA with the amine group of PANI might be a driving force for self‐assembling hollow microspheres, while the hydrogen bond through hydrogen and oxygen of the adjacent SA doped on the polymer chains results in short‐range order of the counter‐ions along the polymer chain in the nanotubes.

One‐Dimensional Conducting Polymer Nanostructures: Bulk Synthesis and Applications

“…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.…”

Conductive gelatin methacrylate-poly(aniline) hydrogel for cell encapsulation

“…Studies involving PANi have been extensively centered around the seeding of cells on pre-fabricated PANi films, as synthesis of 2D thin films can be processed quite easily with current manufacturing methods such as inkjet printing, casting, self-assembly, and electrospinning. [21][22][23][24][25] The use of PANi in engineering cell-laden three-dimensional biomimetic constructs has been limited due to its difficult and non-biocompatible processing steps and its insolubility in common solvents. [17,[26][27][28] Previously, we have reported that PANi can be integrated with synthetic PEGDA and naturally derived gelatin methacrylate (GelMA) hydrogels in situ in order to develop 3D conductive-hydrogels that are sufficiently biocompatible with seeded cells.…”

Synthesis of rectangular tubes of polyaniline/NiO composites

“…Zeolite, 5 porous alumina, 11 and polymer fibers 12 have been used as hard templates to synthesize PANI nanotubes and nanofibers. Organized molecular assemblies of micelles, [13][14][15][16][17][18] inverse micelles, [19][20][21] and lamellar liquid crystals 22,23 have been applied as soft templates to obtain various morphologies of PANI, such as nanotubes, nanorods, nanofibers, and hollow microspheres. Wan and Li 24 also proposed a template-free method for fabricating microtubes of PANI in the presence of b-naphthalene sulfonic acid as a dopant.…”