One-step reverse micelle polymerization of organic dispersible polyaniline nanoparticles

Organic solvent dispersible dodecylbenzenesulfonic acid (DBSA)-doped polyaniline (PANI) was prepared from DBSA micelles with ammonium persulfate (APS) as an oxidant in hexane by one-step polymerization. Morphology observation showed PANI–DBSA powder polymerized with 0.0375 mol DBSA consisting of spherical particles having diameters of 40–60 nm that formed irregular aggregates with about 1 μm diameter. Polymerization was carried out in the hydrophilic aqueous microdomains of micelle dissolved reactants. The experimental conditions were optimized for direct synthesis of DBSA-doped PANI with high electrical conductivity by adjusting various reaction conditions. This research showed the importance of adjusting reaction conditions such as DBSA, aniline, ammonium persulfate, and acidity for polymerization. It was also found that a portion of an electrically neutral anilinium–DBSA complex could be assembled into reverse micelles together with DBSA molecules, where DBSA and anilinium–DBSA acted as both surfactants and doping agents to achieve nano-scaled DBSA-doped PANI with high conductivity. The doping level of DBSA in PANI particles was studied by UV–vis spectroscopy and X-ray diffraction (XRD). From TG/DTA/mass spectrometry, it was found that the PANI–DBSA was doped with both free and bound DBSA.