Self-organized micelles of new renewable resource amphiphilic azobenzenesulfonic acid anionic surfactant were utilized to prepare water-soluble, luminescent, and highly ordered polypyrrole nanomaterials. The micellar behavior of the reaction medium was precisely controlled by varying the composition of pyrrole/surfactant ratio from 3 to 100 (up to 100 times lower amount of surfactant with respect to pyrrole), and polypyrrole nanospheres of 150-800 nm were prepared. Dynamic light scattering (DLS) and viscosity techniques were employed as tools to trace the factors, which control the mechanism of polypyrrole nanomaterials formation. DLS studies confirmed that the surfactant exists as in the form of spherical micelles of 4.8 nm diameter in water. Specific viscosity measurement revealed that the pyrrole+surfactant complexes in water exist in the form of either aggregated or isolated micelles depending upon their composition in the feed. SEM and TEM analysis confirmed that the aggregated micellar templates produced coral-like morphology, whereas uniform polypyrrole nanospheres of 150-400 nm were obtained at low micellar concentration. The nanomaterials formation was unperturbed by the variation of the oxidation agents such as ammonium persulphate (APS) or ferric chloride (FeCl3). WXRD analysis of the nanomaterials indicates that the anionic surfactant effectively penetrates into the polypyrrole chains, and a new peak at 2theta = 6.3 degrees (d-spacing = 14 A) was observed corresponding to highly ordered polymer chains. UV-vis and FT-IR confirmed the highly doped state, and the conductivity of the samples was obtained in the range of 10(-1) to 10(-2) S/cm by four-probe conductivity measurements. The azobenzenesulfonic acid anionic surfactant is luminescent in water, and its grafting on the polypyrrole nanospheres enhances the luminescent intensity with the quantum yield in the range of 2 x 10(-3) to 3 x 10(-4).

We report an anionic surfactant approach for size and shape control in polyaniline, polypyrrole, and their polyaniline‐co‐polypyrrole random copolymer nanomaterials. A renewable resource azobenzenesulfonic acid anionic surfactant was developed for template‐assisted synthesis of these classes of nanomaterials. The surfactant exists as 4.3 nm micelle in water and self‐organizes with pyrrole to produce spherical aggregates. The sizes of the spherical aggregates were controlled by water dilution and subsequent oxidation of these templates, produced polypyrrole nanospheres of 0.5 μM to 50 nm dimensions. The anionic surfactant interacts differently with aniline and forms cylindrical aggregates, which exclusively produce nanofibers of ∼180 nm in diameter with length up to 3–5 μM. The template selectivity of surfactant toward aniline and pyrrole was used to tune the nanostructure of the aniline‐pyrrole random copolymers from nanofiber‐to‐nanorod‐to‐nanospheres. Dynamic light scattering technique and electron microscopes were used to study the mechanistic aspects of the template‐assisted polymerization. The four probe conductivity of the copolymers showed a nonlinear trend and the conductivity passes through minimum at 60–80% of pyrrole in the feed. The amphiphilic dopant effectively penetrates into the crystal lattices of the polymer chain and induces high solid state ordering in the homopolymer nanomaterials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 830–846, 2009

Here, we report a unique molecular template approach, for the first time, to study the evolution of the different types of nanomaterial morphologies such as nanofiber, nanorod, nanosphere, and nanotube in a single system without changing their chemical composition or polymerization route. A renewable resource surfactant was self-organized with aniline (95%) and pyrrole (5%) in water to produce white emulsion consisting of long-range cylindrical micellar aggregates. The dilution of the emulsion with water resulted in the transformation of cylindrical to vesicular aggregates without any phase separation. The size and shape of the cylindrical and vesicular template aggregates were confirmed by dynamic light scattering and electron microscopic analysis. The chemical oxidation of the cylindrical templates produced nanofibers and nanorods, whereas hollow spheres and nanotubes were produced by vesicular templates. The nanofibers were found as long as 4-5 microm length with 200 nm widths, whereas the nanorods were shorter in length (0.5-0.7 microm) with 80-120 nm diameter. The hollow spheres were obtained in 1 mum diameter with wall thickness of approximately 80 nm. The length of the nanotubes was found to vary from 1.2 to 1.8 microm. The average wall thickness and inner pore diameter of the nanotubes were found as approximately 30 nm and approximately 60 nm, respectively. The size and shape of the template aggregates match very well with that of the synthesized nanomaterials and provide direct evidence for the template-assisted evolution of the nanostructure morphology. NMR, FT-IR and UV-visible spectroscopies were utilized to confirm the structure and electronic properties of the nanomaterials. Wide angle X-ray diffraction and transmission electron microscopy-electron diffraction analysis revealed that the nanotubes possessed three-dimensional lamellar-type solid states ordering with high percent crystallinity up to 60%. Variable temperature four-probe conductivity measurements of all samples showed typical I-V plots. The conductivity of the nanofibers was found one order higher than that of nanorod, hollow sphere, and nanotubes at all temperatures. The present investigation enabled us to establish the role of various types of nanomorphologies on properties of nanomaterials such as conductivity and solid state ordering without change in their chemical composition.