New amphiphilic sulfonic acid dopant-cum-templates for diverse conducting polyaniline nanomaterials

摘要

We report new structurally identical polar head amphiphilic sulfonic acids as molecular templates to study the role of the polymerization routes on the solid state properties of polyaniline nanomaterials. Three long chain substituted phenols such as 3-pentadecylphenol, renewable resource-cardanol, and nonyl phenol are reacted with sultones to make new long tail amphiphiles. The amphiphilic molecules self-organized as 4-6 nm tiny micelles in water which were employed as templates for polymerization. Emulsion, dispersion, and interfacial polymerization of aniline along with these new amphiphiles produced well-defined polyaniline nanofibers, nanotapes, and nanospheres. Electron microscopic analysis revealed that the dopant structure and polymerization routes determine the morphology of the polyaniline nanomaterials. Absorbance studies revealed that the samples produced via interfacial route showed expanded polymer chain conformation as a result of unidirectional growth of the chains in the aqueous-organic interface. Emulsion and dispersion route samples were produced in coil-like chain conformation. Powder X-ray analysis confirmed that the expanded conformation in the polyaniline backbone enhances the high solid state ordering, high percent crystallinity, and larger crystallite size compared to that of the samples with coil-like conformation. Highly ordered interfacial route samples showed conductivity three orders of magnitude higher than that of the weakly packed polyaniline nanomaterials.