Bio-inspired Multifunctional Graphene–Epoxy Anticorrosion Coatings by Low-Defect Engineered Graphene

Abstract

Although graphene has been regarded as the most ideal anticorrosion filler, to date, some vital problems including poor dispersion, disordered arrangement, structure defects, and galvanic corrosion remain unresolved,, thus blocking its potential application in metal protection. In this work, a bio-inspried multilayered graphene–epoxy composite coating was fabricated through a scalable spraying approach with well-dispersed low-defect engineered graphene as the functional filler. Polydopamine served as an enforcer to improve the dispersity and repair the structure defects of graphene (π–π interaction) and bridged the dense graphene layers and epoxy layers (strong adhesion) for forming “interlock” structures to ensure complete coating systems. Electrochemical tests confirmed that the bio-inspired composite coating showed elevated coating resistance from 4.2 × 106 Ω cm2 for blank coating and 2.5 × 108 Ω cm2 for blending composite coating to 3.0 × 109 Ω cm2. The highly anisotropic graphene layers endowed the bio-inspried coating with highly anisotropic thermal and electrical conductivities, with the in-plane and through-plane thermal conductivities being 0.78 and 0.21 W/mK, respectively. Besides, the good anisotropic conductivities make the bio-inspired coating achieve self-monitoring of structural safety and health. This bio-inspired strategy provides a fascinating method for constructing high-performance graphene composite coatings with functional properties.

Improved Interfacial Interactions of Dip Coatings by In Situ Introducing Silica to Enhance Corrosion Resistance and Metal Bonding Strength

“…A notable feature of epoxy resins is their excellent adhesion properties. Nanoparticles can be firmly adhered to the interior of the epoxy resins by introducing nanotechnology into epoxy-based coatings, resulting in various types of resin matrix nanocoatings. − Ordinarily, nonuniform nanoparticles doped within resin matrix coatings have a high potential to cause poor corrosion resistance in the resultant coatings. On the other hand, the interfacial air retention after nanoparticle doping may allow the resultant coating to experience osmotic pressure when in corrosive medium, thereby resulting in a reduction in corrosion resistance.…”

“…However, the impedance modulus of pure epoxy coatings is 6 orders of magnitude higher. − In this case, researchers have concentrated their efforts on the development of epoxy-based coatings with nanoparticle doping to further improve the anticorrosion properties. To date, graphene, carbon nanotubes or nanofibers, polyaniline, MOF, and MXene have been doped into epoxy resins to enhance the corrosion resistance of the resultant coatings. The impedance modulus of coatings made using resin matrix nanocomposites barely exceeds 10 9 Ω·cm 2 , particularly when using a one-step dip coating method.…”

Photothermal-Responsive Wormlike Polydopamine-Wrapped Ethylene-Vinyl Acetate Copolymer toward Triple-Action Self-Healing Anticorrosion Coating

“…10b). 75 Thus, the remaining corrosion products on steels surface were iron hydroxides, as illustrated in Figure 10c and confirmed in Figure 10a. For the steel coated with PDA@EVA/EP (Figure 10d), the PDA@ EVA could rapidly obtain the NIR energy and transform it to heat, causing the local temperature above T g at the artificial scratch.…”

“…Beneath pure EP, the main components of corrosion products were γ-FeOOH (1020 cm –1 ) and α-FeOOH (615 cm –1 ). , Especially, a characteristic peak at 1512 cm –1 corresponding to the shear vibration of N–H was observed beneath PDA@EVA/EP, besides a broad adsorption peak exhibited around 3500–3000 cm –1 , ascribing to stretching vibration of catechol and secondary amino groups. , These observations proved the existence of PDA on the steel surface, supporting the possibility of PDA on inhibiting metal corrosion. Raman characterizations also were applied to investigate the corrosion products composition (Figure b), mainly involving γ-FeOOH (213 and 1308 cm –1 ), α-FeOOH (276 and 385 cm –1 ), and Fe 3 O 4 (691 cm –1 ). − The presumable reaction process of different types of corrosion products generated beneath pure EP could be clarified as follows: The fast infiltration of aggressive species (such as O 2 , H 2 O, and Cl – ions) through the opened scratch channel resulted in the damage and dissolution of lots of generated Fe 2 O 3 (main component in Fe 3 O 4 ) (Figure b) . Thus, the remaining corrosion products on steels surface were iron hydroxides, as illustrated in Figure c and confirmed in Figure a.…”

Polymer/Graphene Nanocomposite Membranes: Status and Emerging Prospects

“…Graphene-based nanocomposites possess a high electrical conductivity, thermal conductivity, thermal stability, chemical stability, and mechanical sturdiness features [48]. Graphene-based nanocomposites have been utilized in membranes [49,50], anticorrosion coatings [51], electronics [52], sensors [53], energy storage devices [54,55], batteries [56], microbial fuel cells [57], and tissue engineering [58]. Graphene-based nanocomposites possess a high electrical conductivity, thermal conductivity, thermal stability, chemical stability, and mechanical sturdiness features [48].…”