Exchange Interactions Drive Supramolecular Chiral Induction in Polyaniline

The focus of this paper is on the intermolecular interaction active between polyaniline (PANI) and 10-camphorsulfonic acid (10CSA). Enantiopure 10CSA, present in the electropolymerization solution, promotes chiral induction in the supramolecular polyaniline polymer (cPANI). Tight integration of experimental data (circular dichroism, CD, near edge X-ray absorption spectra, NEXAFS, conductive probe atomic force microscopy, CP-AFM) and theoretical [density functional theory, (DFT)] results allows to unfold the nature of the electronic interaction between PANI and 10CSA and to shed light on the physical interactions inducing the chiral character to bulk pristine non-chiral PANI: eventually yielding cPANI. The electropolymerization follows a "wet chemistry" method: electrochemical polymerization of aniline in the co-presence in bulk solution of enantiopure 10-camphorsulfonic acid (10CSA). The latter is exploited as chirality inductor. The method of integration between experimental results with ab-initio theoretical calculations, strongly suggests that the chiral induction exerted by the CSA stems from exchange interaction between CSA and PANI.