Nafion-Endowed Graphene Super-Anticorrosion Performance

Abstract

Application of graphene (Gr)-reinforced green waterborne epoxy (WEP) coatings faces two major challenges: one is the usage of hydrophilic dispersants that can weaken the interactions between emulsifiers/WEP, resulting in demulsification of the WEP matrix, and the other is the "corrosion promotion activity (CPA)" originated from the high electric conductivity of Gr itself, which restricts the long-term anticorrosion capability. Herein, effective electrostatic-driven exfoliation of graphite into few-layer functionalized Gr nanosheets (nGNSs) was achieved, in which the strong interaction between Nafion (NA) and graphite caused a high yield of 65% under liquid sonication. Due to the surface-protective function of NA, the as-exfoliated nGNSs exhibited good electrical insulation and self-assemble parallelly in the WEP matrix. Electrochemical results confirmed that the nGNSs/WEP coatings displayed extraordinary and durable corrosion protection for carbon steel substrates. With the addition of only 0.3 wt % nGNSs, the corrosion rate of the WEP coatings reduced by 450 times after 120 days of immersion in 3.5 wt % NaCl (aq) . Furthermore, scratch experiments clearly verified that the reduced graphene oxide (rGO) had a typical CPA effect but the nGNSs did not. All of these results suggested that the nGNSs provide an appealing approach toward the preparation and application of graphene-based coatings, with great implications for high-performance anticorrosion of WEP coatings.

Enhancing the Anticorrosion Performance of Graphene–Epoxy Coatings by Biomimetic Interfacial Designs

“…Graphene (G), a monolayer carbon sheet, presents great mechanical strength, chemical stability, and impermeability. − Embedding G in a polymer matrix can enhance the anticorrosion performance of composite coatings by increasing the diffusion pathways of aggressive species, for example, dopamine–G–epoxy (EP) coating, nafion–G–EP coating, silicon oxide–G–poly­(vinyl butyral) (PVB) coating, pernigraniline–G–PVB coating, etc. Despite recent progresses, many practical problems still remain unsolved.…”

Experimental and Theoretical Studies of the Corrosion Inhibition Performance of Fatty Acid-based Ionic Liquids for Mild Steel in 1 M HCl: Effects of the Varied Alkyl Chain Length in the Anionic Group

“…For decades, the employment of corrosion inhibitors was identified as an effective and feasible method to reduce corrosion damage to mild steel in an acid medium. Organic inhibitors, usually with hetero atoms and aromatic rings, could adsorb and generate the protective film on the metal surface to avoid corrosion. − Even though they could inhibit corrosion effectively, the toxicity and environmental harm constrain their development. Nowadays, research and development of excellent replacements for the traditional organic inhibitors are still an urgent need.…”

Air-Stable Titanium Carbide MXene Nanosheets for Corrosion Protection

“…In recent decades, the development of nanotechnology provides potential opportunities for anticorrosive polymer coatings. The application of two-dimensional (2D) nanomaterials, for instance graphene (Gr), boron nitride (BN), transition metal dichalcogenides (MoS 2 and WS 2 ), natural mica, hydroxyapatite (HAp), and metal organic framework nanosheets, has caused innovative anticorrosion coating designs. Research studies have confirmed that Gr displays the enhanced anticorrosion performance because of its completely impermeable properties for all gases, liquids, and ions. − However, Gr has high electrical conductivity and is cathodic to most metals, which can lead to dangerous local galvanic coupling that degrades the metals catastrophically. − …”