Polyaniline nanoparticles for sensing applications.

Conducting polymers are being widely employed in the manufacture of nanostructured sensors due to breakthroughs in the development of sophisticated nano-sized forms. One of the most attractive conducting polymers is polyaniline (PANI) due to its interesting electrical, electrochemical and optical properties, such as air stability and simple acid/base doping/dedoping chemistry. However, the fact that aniline is a carcinogenic monomer, its insolubility in common solvents and the acidic conditions required to the most conductive form of PANI are made its commercial application very difficult so far. The synthesis of PANI nanoparticles using dodecylbenzenesulphonic acid (DBSA) as both dopant and surfactant have allowed the use of this polymer in aqueous media, improving its processability. The additional use of ammonium persulphate (APS) as an oxidant together with DBSA during chemical PANI polymerization have led to the creation of a spherical PANI nanoparticle aqueous dispersion. Such dispersion can be deposited onto the electrodes by means of traditional methods, such as drop coating, or using more sophisticated techniques, such as inkjet printing. The application of PANI nanoparticles inkjet printed onto carbon paste screen-printed electrodes for ascorbic acid sensing is shown in the present wor