Robust Self-Healing Graphene Oxide-Based Superhydrophobic Coatings for Efficient Corrosion Protection of Magnesium Alloys

Abstract

A self-healing coating possesses a broad application prospect in the metal corrosion protection area due to its pleasurable performance. By far, despite a great deal of research studies that have been reported in this field, it is still a challenge to construct an intrinsic self-healing surface that can repair a damaged structure and restore superhydrophobicity simultaneously. Herein, a self-healing superhydrophobic coating was fabricated by combining polydopamine (PDA)-functionalized Cu 2+ -doped graphene oxide (GO), octadecylamine (ODA), and polydimethylsiloxane (PDMS), which can recover the superhydrophobicity and microstructure of the coating after chemical/physical damage. The as-prepared self-healing coating displayed excellent liquid repellency with a water contact angle of 158.2 ± 2°and a sliding angle of 4 ± 1°, which endowed the Mg alloy with excellent anticorrosion performance. Once the coating is scratched, the local damaged structure will be automatically repaired through the chelation of catechol and Cu 2+ . Also, the superhydrophobicity of the coating can be rapidly restored under 1-sun irradiation even after being etched by O 2 plasma. Furthermore, the as-fabricated self-healing coating still exhibited excellent corrosion protection against a magnesium alloy after immersion in 3.5 wt % NaCl solution for 30 days, which was attributed to the efficient repair of defects in GO by PDA through π−π interactions and the inherent chemical inertia of PDMS. Moreover, the as-fabricated self-healing coating also exhibited favorable mechanical stability, chemical durability, and weather resistance. This study paves a fresh insight into the design of robust self-healing coatings with huge application potential.

Aqueous construction of raspberry-like ZIF-8 hierarchical structures with enhanced superhydrophobic performance

“…The water contact angles (WCAs) were measured with liquid droplets of 5 μL on a Dataphysics OCA20 Contact-Angle System. 35…”

“…The water contact angles (WCAs) were measured with liquid droplets of 5 μL on a Dataphysics OCA20 Contact-Angle System. 35 The finger-wipe test was performed by wiping the coated substrate with fingers to test the robustness, where each wipe is considered as 1 cycle of abrasion. The sandpaper abrasion behaviors of the superhydrophobic coatings were evaluated by placing hydrophobic-treated paper under a weight of 50 g face down on 800-mesh sandpaper, and moving it 10 cm along the ruler, which is defined as 1 cycle of abrasion.…”

Current research situation and future prospect of superwetting smart oil/water separation materials

“…Particularly, special wettability is usually used to describe the extremely wetting behavior of the liquid at the liquid/air/solid or water/oil/solid interface with a contact angle (CA) greater than 150 or less than 10 , which is attractive for self-cleaning, antiicing, printing, water collection, liquid transfer, corrosion resistance, gas separation, seawater desalination, and oil/water separation. [24][25][26][27][28][29][30][31][32][33][34][35][36] In the eld of oil/water separation, "oilremoving" materials with superhydrophobic/superoleophilic property can selectively separate oil from oil/water mixtures or oil/water emulsions. 37 Alternatively, materials with superhydrophilic/superoleophobic ability are known as "waterremoving" materials.…”

Pebax and CMC@MXene-Based Mixed Matrix Membrane with High Mechanical Strength for the Highly Efficient Capture of CO2

“…Therefore, an energy-saving and efficient method to capture CO 2 from the flue gas and natural gas is urgently needed to curtail CO 2 emissions. − Amine-based solvents are a mature technology for CO 2 capture in traditional separation methods, but it suffers from significant drawbacks, such as high energy costs and potential environmental risks. Compared with the traditional amine-based solvent absorption separation method, membrane separation possessing the low-cost, no phase transition, and environmentally friendly characteristics is extensively adopted to remove CO 2 from gas mixtures. − During the membrane process, the performance of CO 2 separation membranes is usually evaluated by permeance and selectivity. As for the gas separation membrane, maintaining appropriate selectivity while improving permeance has been considered an important consideration for its practical applications. , However, traditional polymer membrane materials face a trade-off between permeability (permeance) and selectivity, which limits the CO 2 separation efficiency through the membrane processes. , …”