Mechanical Stability Strengthening Of Superhydrophobic Coatings And Their Marine Corrosion Protection Performance

The corrosion problem of marine metals is a serious threat to the safe service of marine engineering.Studies have shown that bionic superhydrophobic surfaces can effectively inhibit the corrosion behavior of metals,showing great potential and application value in marine corrosion protection.However,the rough structure of superhydrophobic surfaces exhibits poor mechanical strength,which limits its application in practical marine environments.Therefore,how to strengthen the mechanical stability of superhydrophobic surfaces is one of the key issues to promote the application of superhydrophobic materials in marine corrosion protection.In this work,we aimed to enhance the stability of superhydrophobic surfaces,designed and developed a series of highly stable superhydrophobic coatings from various perspectives,including interfacial bonding,self-healing and elastic deformation,proposing a mechanism to enhance the stability of superhydrophobic surfaces and evaluating the performance of superhydrophobic coatings for marine corrosion protection.This study provides a theoretical basis for the design and development of highly stable superhydrophobic coatings,and is of great significance to promoting the application of superhydrophobic surfaces for marine atmospheric corrosion protection.The main research results are as following.(1)Based on an all-chemical bonding approach,a highly stable superhydrophobic coating with silicate network interfacial strengthening was designed and developed from the perspective of microstructures/substrate interfacial adhesive strengthening,and the interfacial strengthening mechanism of the silicate network on the superhydrophobic coating was investigated as well as its corrosion protection performance against metals was evaluated.It was found that a silicate network structure with Si–O–Si bonding was formed inside the coating,which increased the chemical interaction and interfacial adhesion between different components(water glass,particles,matrix and perfluorosiloxane),and thus enhanced the mechanical stability of the superhydrophobic coating.Highly stable superhydrophobic coatings based on full chemical bonding showed excellent mechanical stability,chemical durability,and universality.Furthermore,the superhydrophobic coatings exhibited excellent corrosion resistance based on the physical barrier effect of the surface air film.(2)Based on a thermal healing-assisted approach,a highly stable superhydrophobic coating with thermal healing-assisted interfacial strengthening of the interlayer was designed and developed from the perspective of self-healing of the interlayer at the microstructures/substrate interface,and the effect of the self-healing interlayer on the self-healing and mechanical stability of the superhydrophobic coating was investigated as well as its corrosion protection performance against metals was evaluated.It was found that the self-healing interlayer at the microstructures/substrate interface not only increases the interfacial adhesion and mechanical interlocking between the microstructures and the substrate by chemical bonding and physical anchoring,but also enhances the damage resistance of the coating by thermal healing,in turn enhancing the mechanical stability of the superhydrophobic coating.Highly stable superhydrophobic coatings based on thermal healing assistance presented superior water repellency,mechanical stability,chemical durability,self-cleaning,antipollution capability,and thermogenic self-healing.Furthermore,based on the physical barrier effect and self-healing of surface air film and self-healing interlayer,the superhydrophobic coatings exhibited corrosion protection specificity of surface layer repellency,interlayer barrier,scratch immunity,and an overall repairability,and also exhibited sustained and long-lasting corrosion protection.(3)Based on a photo healing-assisted approach,a high-stability superhydrophobic coating with photohealing-assisted interfacial strengthening of the interlayer was designed and developed from the perspective of self-healing of the interlayer at the microstructures/substrate interface,and the influence of the stability of the interlayer on the stability of the superhydrophobic coating was investigated as well as its corrosion protection performance against metals was evaluated.It was found that,on the one hand,the polyurethane interlayer enhanced the mechanical stability of the superhydrophobic coating based on the self-healing interlayer interfacial strengthening mechanism;On the other hand,the high healing temperature interlayer achieves inertness of the polymer network below moderate temperature at the microstructures/substrate interface,enhancing the impermeability of the microstructures on the self-healing interlayer surface,in turn strengthening the room temperature storage stability of the superhydrophobic coatings.Highly stable superhydrophobic coatings based on photo healing assistance exhibited outstanding room temperature stability,mechanical stability,chemical durability,self-cleaning,anti-pollution capability,and photogenic self-healing.Furthermore,based on the physical barrier effect and self-healing of surface air film and self-healing interlayer,the superhydrophobic coatings exhibited corrosion protection specificity of surface layer repellency,interlayer barrier,as well as target,remote and rapid repairability.(4)Based on an elastic deformation-assisted approach,a highly stable superhydrophobic coating with elastic deformation-assisted interfacial strengthening of the interlayer at the microstructures/substrate interface was designed and developed from the perspective of energy storage of the interlayer,and the effect of the elastic modulus of the interlayer on the interfacial strengthening of the superhydrophobic coating was investigated as well as its corrosion protection performance against metals was evaluated.It was found that the elastic interlayer at the microstructures/substrate interface not only increased the interfacial adhesion and mechanical interlocking between the microstructure and the substrate by chemical bonding and physical anchoring,but also buffered the external impact energy and enhanced the impact resistance of the coating by elastic deformation,in turn enhancing the mechanical stability of the superhydrophobic coating.Highly stable superhydrophobic coatings based on elastic deformation assistance demonstrated remarkable water repellency,wear and impact resistance,chemical durability,self-cleaning,and anti-pollution capability.Furthermore,based on the physical barrier effect of surface air film and interlayer,the superhydrophobic coating exhibited the dual physical barrier properties of surface layer repulsion and interlayer barrier.