Enhanced electroactivity at physiological pH for polyaniline in three-dimensional titanium oxide nanotube matrix

The electroactivity of polyaniline (PANI) can be solely retained in acidic media. However, the acidity requirement greatly limits its potential applications such as biosensors and anticorrosion, where neutral circumstances have to be faced. Herein, PANI is conformally loaded into anodic titanium oxide (ATO) nanotubes by electrode-position. The prepared PANI-ATO hybrid films exhibited excellent electroactivity and high redox stability in neutral media, which can be ascribed to the intercalation of protons in the ATO layer and the diffusion confinement in three dimensional tubular nanostructures. The results provide a rational design guideline to achieve the electroactivity of PANI in neutral circumstances, which may have immediate impact on bioelectronic applications.