Variation in the conductivity of polyaniline nanotubes during their formation

It is shown that the method for the growth of conducting polyaniline nanotubes, based on the direct polymerization of aniline on the surface of channels in track membranes, can be used to produce nanotubes with a given conductivity. An island-type film with a channel resistance of $\sim$10$^{19}\Omega$ is formed during the initial stage of polymerization (up to 2 min). As the polymerization duration increases to 3 min, the channel resistance falls by more than 10 orders of magnitude. This is attributed to the formation of a continuous film on the channel surface, i.e., a nanotube is formed. With the polymerization duration increasing further, the channel (nanotube) resistance gradually decreases to $\sim$10$^{19}\Omega$ at 10 min. The conductivity of polyaniline during the formation of a hollow nanotube is estimated to be 0.01–0.04 S/cm. If the nanotube is completely filled with polyaniline, the conductivity increases to $\sim$0.2 S/cm.