EIS Evaluation and Synthesis Nylon/Graphene Oxide Electrospun Composite Coating

Graphene has attracted strong scientific and technological interest in recent years, and. It has shown great promise in many applications because of its unique physicochemical properties: high surface area (theoretically 2630 m²/g for single-layer graphene), excellent thermal and electric conductivity, and strong mechanical strength. Many methods have been developed to produce graphene. In general, nylon 6-6 has excellent mechanical resistance due to the mutual attraction of their long chains and their crosslinking. Since nylon discovery, a great interest has been developed due to its technological importance, its commercial characteristic, and its complexity related to the morphological changes associated to its crystallinity, not only in solid state, but also in solution and under melting point conditions.

A possible application for nylon 6-6/graphene oxide composite film is as a anticorrosion coating on the stainless steel bipolar plate for PEMFC due to the possible decrease of aggressive species diffusion through the coating as well as facilitating the electron discharge of the cathodic reaction, therefore diminishing the metal degradation and eliminating the passive layer that causes unacceptable reduction in contact resistance and possible fouling of the catalyst and the ionomer.  

Starting from exfoliated graphite, different treatments were tested in order to obtain the best graphite oxide conditions. These included: calcination in a muffle for two hours at 700 or 800 °C. After that, ultrasonic agitation for three hours in acidic, basic or peroxide solutions was performed. Afterwards, particles were rinsed, filtered and dried at ambient temperature. These samples were characterized under SEM and FTIR techniques. Electrochemical cells were prepared using porous silica or nylon films as substrate covered with graphite oxide for further oxidation and reduction by electrochemical procedures. Polarization curves were performed to determine the best oxidation/reduction potentials under different acidic, alkaline and peroxide solutions. The best oxidation condition was obtained in KOH and the best reduction in H₂SO₄solutions. With these results potentiostatic oxidation and reduction curves were applied to further oxidize carbon species and then, reduced them onto the porous silica or nylon surface forming the graphite film.

 Keywords: nylon, grapheme, electrochemical, synthesis.

 Presenting author’s email: cesar.garcia@uaem.mx