D Wei - Process Chemistry Centre, c/o Laboratory of Analytical Chemistry
A Pivrikas - Centre for Functional Materials
H Karhu - Department of Physcis, University of Turku
A Ivaska - Process Chemistry Centre, c/o Laboratory of Analytical Chemistry

A new method has been developed to combine surface modification of indium-tin oxide (ITO) and electropolymerization to prepare well ordered nanostructured sulphonated polyaniline (SPAN) films with good surface coverage. The surface modification enhances the growth of the SPAN film resulting in a better rectification signal for SPAN films polymerized on unmodified ITO substrates. The films were characterized by FTIR, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The sulphonation degree of SPAN was determined to 29% by X-ray photoelectron spectroscopy (XPS). UV-VIS spectroscopy shows that the pH sensitivity of SPAN is suppressed due to sulphonation of the polymer backbone

organic diode; sulfonated poly(aniline)