Synthesis of polyanthranilic acid-Au nanocomposites by emulsion polymerization: development of dopamine sensor

Polyanthranilic acid (PANA) and polyanthranilic acid-gold (PANA-Au) nanocomposites have been synthesized through emulsion polymerization technique. Use of gold chloride as an oxidant for anthranilic acid not only provides a new route for chemical synthesis of PANA, but also explores a facile method for the formation of nanocomposites. Emulsion polymerization helps in slowing down kinetics of polymerization in comparison to one-phase polymerization and thereby induces formation of monodispersed, both pure and Au nanoparticles, embedded PANA sphere. Reaction progress of nanocomposite formation is studied by UV-Vis spectroscopy for 0-24 h. PANA-Au nanocomposites are characterized by SEM, equipped with EDS, TGA, FT-IR, XRD and electrochemical techniques. XRD of nanocomposites depicts the amorphous nature of polymer and crystalline nature of Au with crystallite size of similar to 24 nm. Differential pulse voltammetry has shown the electro-active nature of PANA. The nanocomposites with improved thermal properties show good dispersion in common organic solvents, and it can be explored for application in interference-free dopamine sensors with sensitivity 12.5 mu A/mM. Acidic group (-COOH) on the polymer makes the sensor free from ascorbic acid interference.