CHEMICAL GENERATION OF OPTICALLY-ACTIVE POLYANILINE VIA THE DOPING OF EMERALDINE BASE WITH (+)-CAMPHORSULFONIC OR (-)-CAMPHORSULFONIC ACID

Optically active polyaniline salts can be readily generated in solution via the enantioselective acid doping of the neutral emeraldine base form of aniline with either (+)- or (-)-camphorsulfonic acid in a variety of organic solvents (1-mehhyl-2-pyrrolidinone (NMP), dimethylformamide, dimethylsulfoxide, CHCl3). Strong mirror-imaged circular dichroism (CD) spectra were observed for the deep green polymer solutions obtained with (+)- and (-)-camphorsulfonic acid (HCSA), respectively, suggesting that the acid doping is enantioselective, with one helical screw of the polymer chain being preferentially produced depending on which hand of the CSA(-) anion is incorporated. In contrast, no CD bands were observed for related polytoluidine salts in NMP, consistent with a model proposed for the above enantioselectivity. Films of the optically active polyaniline salts were also obtained by casting from the acid-doped solutions onto glass plates, and showed similar CD spectra.