Synthesis and characterization of polythiophenes prepared in the presence of surfactants

In this study homopolymers of thiophene were synthesized by chemical oxidative polymerization in the presence of three different surfactants (anionic, cationic and non-ionic) and an oxidant in an anhydrous medium. An anionic surfactant, sodium dodecylbenzenesulfonate (DBSNa), a cationic surfactant, tetradecyltrimethylammonium bromide (TTAB) and a non-ionic surfactant, poly(ethylene oxide) (20) sorbitan monolaurate (Tween 20), were used as additives. The properties of the polythiophenes (PTs) prepared were studied and compared with those of surfactant-free polythiophene (PT). PTs were characterized by different techniques: FTIR spectroscopy, elemental analysis, scanning electron microscopy, thermogravimetry and conductivity measurement. The scanning electron micrographs of PT prepared in the presence of surfactants showed differences in the surface morphologies for different surfactants. PT prepared in the presence of cationic and non-ionic surfactants exhibited smooth surfaces, while a typical globular structure was found for surfactant-free PT. PT synthesized with a cationic surfactant showed the highest thermal stability of all the samples.