Synergistic effect of graphene polyindole nanocomposite for enhanced corrosion protection of aqueous coating in 3.5% NaCl solution for low carbon steel

Abstract

Graphene polyindole (Gr@PIn) nanocomposite with varying content of graphene was synthesized via an in‐situ redox polymerization doping technique. The techniques like FT‐IR, XRD, SEM, and TEM were utilized to characterize the produced nanocomposites. The produced nanocomposites were cast on LCS (low carbon steel) substrate employing NMP as a solvent, 10% epoxy as a binder, and triethylenetetramine as a curing agent. The anti‐corrosion ability of the Gr@PIn nanocomposite coatings was established by performing corrosion tests such as OCP, EIS, PDP measurements, Salt spray test, and Wettability test. Gr@PIn coating was observed as an effective anti‐corrosion coating for LCS substrate in 3.5 wt.% NaCl. The anticorrosion behavior of coating was dependent on graphene content; the higher content of graphene providing higher protection. The anticorrosion performance of Gr@PIn nanocomposite coating was also compared with that of Polyindole (PIn) coating and bare steel.

Polythiophene (PTh)–TiO2–Reduced Graphene Oxide (rGO) Nanocomposite Coating: Synthesis, Characterization, and Corrosion Protection Performance on Low-Carbon Steel in 3.5 wt % NaCl Solution

“…rGO was synthesized by the oxidation of graphite powder according to the Hummers modified method, as described in our previous paper. 31 …”

“…The order of positive shift in OCP of coated steel is as follows: PTh-TiO 2 -rGO > PTh-TiO 2 > PTh. The more positive shift in the values of OCP indicates their high corrosion resistance, which is a result of both barrier existence and the passive oxide layer effect at the coating interface. − The presence of rGO and TiO 2 in the PTh-TiO 2 -rGO nanocomposite coating has shifted the potential in a more noble direction and improved the coating’s redox behavior and barrier characteristics . The higher corrosion protection ability of the PTh-TiO 2 -rGO and PTh-TiO 2 nanocomposite coatings over PTh for the full immersion time is due to a superior barrier effect, i.e., changes caused by the formation of a more adhesive, dense, and uniform layer on the steel surface.…”

“…rGO was synthesized by the oxidation of graphite powder according to the Hummers modified method, as described in our previous paper. 31 Synthesis of PTh, PTh-TiO 2 , and PTh-TiO 2 -rGO Nanocomposite. We used an in situ chemical oxidative polymerization approach to make PTh, PTh-TiO 2 , and PTh-TiO 2 -rGO nanocomposite in chloroform, with anhydrous FeCl 3 as an oxidizing agent.…”

Polyindole and polypyrrole as a sustainable platform for environmental remediation and sensor applications

“…Polyindole (PIN), a rising conducting polymer, is being explored and developed as a possible candidate for electrochromic devices 33,34 , sensors 35,36 , photocatalysis 37,38 , and electrocatalysis 39 , anticorrosion 40,41 , diodes 42,43 , supercapacitors 44,45 , batteries, and biology-related applications [45][46][47] . The studies on PIN has been started as early as 1976, Youmans, H. L et.al synthesised polyindole from indole through chemical polymerization 48 .…”

Recent trends and advances in polyindole-based nanocomposites as potential antimicrobial agents: a mini review

“…Several studies on polyindole revealed that they could be used as promising candidates for applications such as supercapacitors, batteries, electrochromic devices, sensors, electrocatalysis, catalysis, and anticorrosion. 77–83 Graphene and silver nanoparticles loaded polyindole have been subjected to electro activity studies and found that such system can be used as an electrode material for various applications. 84…”