Optically active sulfonated polyanilines

The water soluble sulfonated polyaniline, poly(2-methoxyaniline-5-sulfonic acid), has been prepared in optically active form via the electropolymerisation of 2-methoxyaniline-5-sulfonic acid in the presence of (R)-(+)- or (S)-(−)-1-phenylethylamine. The polymer films deposited on ITO-coated glass with the enantiomeric amines exhibited intense, mirror imaged circular dichroism spectra in the visible region. This enantioselectivity in the polymerisation/deposition is attributed to the respective chiral amines inducing a preferred one-handed helical structure to the sulfonated polyaniline chains via acid–base interactions. The optical activity and electroactivity of the chiral polymers are retained after their immobilisation on poly(4-vinylpyridine).