LAUSR

Abstract We report, for the first time, the use of a bile salt, the sodium taurocholate (Tch), as a surface-active agent in the emulsion synthesis of electroactive polypyrrole (PPy) nanoparticles. PPy was obtained under mild and environmentally friendly conditions, using hydrogen peroxide (H2O2) as a green oxidant. The combined addition of a non-ionic surfactant, Tween 20 (Tw), was also studied. The electrical, structural, morphological, and colloidal properties of reaction products were analyzed in detail to find the best conditions of synthesis. The pre-polymerization emulsion systems were studied by osmometric measurements, isothermal titration calorimetry (ITC), and dynamic light scattering (DLS). A consistent mechanism of nucleation and growth of PPy colloids is proposed. The Tch acts as an emulsifier of the reaction media, a doping agent of oxidized chain of PPy, and a stabilizer of the resulting colloids. The main advantage of this work is the preparation of polymer colloids through a completely green alternative route, which could open up new possibilities for obtaining nanoparticles through an effective and non-toxic method.