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This work presents a comparison between electrochemical (Echem), plasma glow, and arc discharge polymerizations of pyrrole doped with iodine to correlate the energy of synthesis, chemical structure, and electrical conductivity of the polymers. Plasma glow discharges were used in the gas phase, electrochemistry in liquid, and arc discharges in a hybrid gas–liquid combination. Polypyrroles had structure and conductivity that varied with the synthesis parameters; Echem produced polymers with high carbonization and without the C≡N triple bonds resulting from the other syntheses. Conductivity divided the polymers in two: those synthesized in liquid were in the 0.01–1.0 S/m range, and those synthesized in gas were in the 10–9–10–7 S/m range, with differences of up to eight orders of magnitude due to the dopants and electrolytes. [ABSTRACT FROM AUTHOR]

Stainless steel (SS) thin plates were covered with polyaniline (PANI) with consecutive electric glow discharges in H2O2 and in aniline vapors to sensitize the SS surface and to polymerize aniline on the plates. The objective was to form smooth polymeric coatings attached to the metallic surface that resist saline fluids for several months. The coated samples were submerged during 2 months in static and dynamic Phosphate-Buffered Saline solutions with pH = 7.4 at 37 °C to partially simulate the chemical conditions of an implant in the circulatory system. The results indicated that in the static fluid, the PANI coating remained adhered to the SS surface with some slight cracks. In the dynamic fluids, 4.6 mL/s, the coatings showed partial detachment of the superficial layers; however, the interior layers remained attached. In both cases, the contact angles on the coating were in the limit between hydrophilic and hydrophobic surfaces. The chemical analysis suggested the formation of O bridges that could contribute to the chemical adhesion of PANI on the SS surface. In general, the results indicated a good potential to retain the polymeric coating on SS under long immersion in saline fluids. [ABSTRACT FROM AUTHOR]