The intrinsic nanofibrillar morphology of polyaniline.

Polyaniline nanofibers are shown to form spontaneously during the chemical oxidative polymerization of aniline. The nanofibrillar morphology does not require any template or surfactant, and appears to be intrinsic to polyaniline synthesized in water. Two approaches--interfacial polymerization and rapidly-mixed reactions--have been developed to prepare pure nanofibers. The key is suppressing the secondary growth that leads to agglomerated particles. The effects of different dopant acids and solvents are discussed. Changing the dopant acid can be used to tune the diameters of the nanofibers between about 30 and 120 nm. Changing the organic solvent in interfacial polymerization reactions has little effect on the product. A brief discussion of the processibility of the nanofibers is presented. The possibility of creating nanofibrillar structures for selected polyaniline derivatives is also demonstrated.