Facile preparation of optically active polyanilines via the in situ chemical oxidative polymerisation of aniline

Optically active polyaniline in the non-doped emeraldine oxidation state and as the polymer doped with HCl have been synthesised via the facile in situ deposition of films from an aqueous solution of aniline undergoing oxidative polymerisation. Films of optically active polyaniline doped with (+)- or (−)-10-camphorsulfonic acid (PAn.HCSA) were first deposited from a solution of aniline by ammonium persulfate in the presence of (+)- or (−)-HCSA. Their UV–visible and circular dichroism (CD) spectra suggest significant structural differences to PAn.HCSA salts prepared electrochemically. De-doping of the in situ deposited films with aqueous NH4OH gave optically active emeraldine base films, which could be re-doped with HCl vapour or 1.0 mol dm−3 aqueous HCl to generate optically active PAn.HCl films with retention of polymer configuration.