Conducting PEDOT nanoparticles: controlling colloidal stability and electrical properties

The synthesis of conducting polymer nanoparticles by oxidative polymerization can be a challenge, because the addition of oxidizers may compromise the colloidal stability of the system. In this work, we report the successful synthesis poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles by means of miniemulsion polymerization. We study the role of oxidizing agents (iron(iii) p-toluenesulfonate and hydrogen peroxide) during the parti- cle formation particles and in the electric properties. The presence hydrogen peroxide is demonstrated to be crucial in the macroscopic stability of the suspensions and the mor- phology of the resulting nanoparticles. The obtained suspensions, containing particles of diameters of around 30 nm, are stable for several months. The electrical conductiv- ity increases with increasing the content of iron(iii) p-toluenesulfonate, but it decreases with addition of hydrogen peroxide, which can be explained by secondary reactions in the polymerization process.