THERMOCHROMISM IN OPTICALLY-ACTIVE POLYANILINE SALTS

Optically active polyaniline salts PAn.(+)-HCSA (HCSA = 10-camphorsulf onic acid) have been shown to have different conformations for their p olyaniline chains depending on whether they are synthesized chemically or electrochemically. These conformations are assigned as ''compact c oil'' and partial ''expanded coil'', respectively. An ''expanded'' to ''compact'' coil transformation is induced by heating to 140 degrees C for 10 min, as evidenced by UV-visible and circular dichroism spectra l studies. At temperatures greater than 180 degrees C, progressive ded oping of the PAn.(+)-HCSA salt films occurs, with the formation of rac emic emeraldine base.