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.

中文翻译：

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Nafion赋予的石墨烯超防腐性能

石墨烯（Gr）增强的绿色水性环氧（WEP）涂料的应用面临两个主要挑战：一个是使用亲水性分散剂，这会削弱乳化剂/ WEP之间的相互作用，导致WEP基质破乳，另一个是“腐蚀促进活性（CPA）”源自Gr本身的高电导率，这限制了其长期的防腐能力。在此，实现了石墨的有效静电驱动剥落成几层功能化的Gr纳米片（nGNSs），其中Nafion（NA）与石墨之间的强相互作用导致在液体超声处理下高产率达到65％。由于NA的表面保护功能，剥落的nGNS表现出良好的电绝缘性，并在WEP基质中平行自组装。电化学结果证实，nGNSs / WEP涂层对碳钢基材显示出非凡且持久的防腐蚀性能。仅添加0.3 wt％的nGNS，浸入3.5 wt％的NaCl中120天后，WEP涂层的腐蚀速率降低了450倍_（水）。此外，刮擦实验清楚地证明了还原的氧化石墨烯（rGO）具有典型的CPA效果，但nGNS没有。所有这些结果表明，nGNS为石墨烯基涂料的制备和应用提供了一种有吸引力的方法，这对WEP涂料的高性能防腐具有重要意义。