H. Aota et al., SYNTHESES AND PROPERTIES OF PI-CONJUGATED POLYMERS CONTAINING CHROMOPHORE .1. WATER-SOLUBLE SMALL-BANDGAP POLYMER BACKBONE, Chemistry Letters, (6), 1997, pp. 527-528
Water-soluble polymers were prepared from pyrrole and sodium o-benzald
ehydesulfonate by addition-condensation polymerization, The bandgap of
the polymer obtained was estimated to be less than 0.5 eV.