Supramolecular chirality control via self-assembly of oligoaniline in the chemical oxidative polymerization process

Abstract

Helical polyaniline nanofibers having a molar ellipticity as high as 5.8 × 10⁵ deg cm² dmol⁻¹ are produced via a self-assembly process of the amine-capped oligoaniline. Our results suggest that chirality control of PANI nanofibers can be achieved by tuning (1) the oligomeric species guiding the aniline monomer growth and (2) the non-covalent interactions including electrostatic and π–π stacking. Detailed mechanistic studies indicate that the growth of PANI nanofibers may influence the optical activity of PANI, and the correlation between the morphology and the optical activity is discussed. The influence of the non-covalent interactions on the chirality of polyaniline is investigated by changing the concentration of CSA and selecting various organic solvents. These PANI helical nanofibers are demonstrated to be reasonably stable after removing the chiral doping acid via CD studies, essential for their potential applications.