Low molecular weight polyaniline nanotubes were prepared by fast emulsion polymerization in the presence of both n -dodecylbenzenesulfonic acid (DBSA) and HCl(aq). The anilinium monomers associated with DBSA emulsifiers were found to self-arrange into strands of associated cylindrical micelles before polymerization, as monitored by their optical activity and optical image. In the presence of some HCl(aq), the monomer-associated cylindrical micelles expanded and the polymerization rate could be speeded up. It was found that the low molecular weight (viscosity-averaged molecular weight) polyaniline obtained can easily lead to the formation of highly conductive, one-dimensional nanotubes or nanofibers monitored by the variation of optical activities and λ max of the UV–visible–near IR spectra during polymerization. The DBSA/HCl ratio played an important role in the eventual properties and morphologies of the one-dimensional polyanilines, which can be illustrated by conductivity, SEM and transmission electron microscopy measurements. The resultant one-dimensional polyaniline nanotubes can be arranged into a layered structure by orientation, illustrated by AFM and wide-angle X-ray diffraction.