Synthesis of diphenylamine-co-aniline copolymers in emulsified systems using a reactive surfactant as the emulsifying agent and aniline monomer

[Display omitted] •Emulsions of diphenylamine are polymerized via oxidative polymerization.•We synthesized copolymers of diphenylamine and aniline in emulsified systems.•A reactive surfactant is used as the monomer of aniline.•The reactive surfactant polymerizes via oxidative polymerization. Poly(diphenylamine) (PDPA) and diphenylamine-co-aniline (DPA/aniline) copolymers were synthesized vía oxidative polymerization in oil in water (o/w) emulsified systems. To obtain emulsified systems, firstly, diphenylamine (DPA) was brought into liquid form by heating above its melting temperature and subsequently, emulsified by applying ultrasound. For DPA homopolymer synthesis, sodium dodecyl sulfate (SDS) was used as the emulsifying agent; however, for the synthesis of DPA/aniline copolymers anilinium dodecyl sulfate (P1), an amphiphile that has the property to perform the functions of surfactant and monomer of polyaniline (PAni) simultaneously, was used. Electron microscopy characterization showed that the products of copolymerization were spherical particles, as expected, considering the characteristics of the emulsified systems (micro-droplets of oil dispersed in an aqueous medium). The characterization by infrared spectroscopy (FTIR), UV–vis and X-ray diffraction (XRD) indicated that the copolymers more strongly preserve the characteristics of the PDPA. In addition, cyclic voltammetry (CV) indicated electro-activity in the products. The comparison between the copolymers and a physical mixture PAni/PDPA (1.0:1.0, w/w), characterized by FTIR and CV reported clear differences, which allowed us to conclude that the products are copolymers and not blends.