Super-Anticorrosive Materials Based on Bifunctionalized Reduced Graphene Oxide

• Published in: ACS applied materials & interfaces 2020-10, Vol.12 (40), p.45254-45265
• Main Authors: Ramírez-Soria, Edgar H, León-Silva, Ulises, Rejón-García, Leonardo, Lara-Ceniceros, Tania. E, Advíncula, Rigoberto C, Bonilla-Cruz, José
• Format: Article
• Language: English
• Subjects: Applications of Polymer, Composite, and Coating Materials
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c11004

The design of new materials with two or more functional groups must be strongly considered to achieve multifunctional coatings with outstanding properties such as active–passive protection against corrosion, low-friction, antifouling, and sensing, among others. In this sense, nanocomposites based on solvent-free epoxy resin/bifunctionalized reduced graphene oxide layers with NH2 and NH3 + groups (ER/BFRGO) with super-anticorrosive properties are for the first time reported here. The amine groups (−NH2) act as cross-linker agents, which react with epoxy terminal groups from resin, thus closing the gap between the BFRGO layers and the polymeric matrix. Meanwhile, the ammonium ions (−NH3 +) are effective trapping agents of negatively charged atoms or molecules (e.g., Cl–). This novel combination enables us to obtain nanocomposite coatings with passive–active protection against corrosion. ER/BFRGO deposited onto A36 mild steel exhibited a remarkably enhanced barrier against corrosion into a saline medium (1 M NaCl; 58.4 g/L), wherein the corrosion current density (i corr) was diminished 6 orders of magnitude (i corr = 5.12 × 10–12 A/cm2), with respect to A36 mild steel coated only with ER (i corr = 2.34 × 10–6 A/cm2). Also, the highest polarization resistance R p = 6.04 × 107 Ω/cm2 was obtained, which represents the lowest corrosion rate and corresponds to 3 orders of magnitude higher than A36 mild steel coated with ER (R p = 1.43 × 104 Ω/cm2). The strategy of bifunctionalization proposed herein to obtain bifunctionalized reduced GO with NH2 and NH3 + groups has not been disclosed in the literature before; in consequence, this work opens a new pathway toward the design of smart materials based on multifunctional nanomaterials.