Design, Preparation And Performance Study Of Underwater High-adhesion Hydrogel Coatings

The excellent underwater superoleophobicity properties of hydrogel coating can give many kinds of underwater equipment surface properties such as antifouling,drag reduction and biological adhesion,etc.In recent years,it has been widely concerned by scholars and industry at home and abroad.Their underwater superoleophobicity is usually caused by its own highly hydrophilic,but it tends to weaken its adhesion to the substrate,and long-term use in water environment because of the destruction of water molecules hydrogel coating from the substrate surface stripping even fall off,thus performance loss of superoleophobicity surface,serious limits its application in actual situations.Marine mussels can rapidly and firmly adhere to various solid surfaces using byssus in wet and underwater environments,and it relies on catechol groups in mussel adhesive proteins to effectively adhere to various substrates through hydrogen bonding,metal coordination,interaction hydrophobic,π-π interaction and ion-π interaction.In this work,the catechol adhesive group was introduced into the polyurethane system inspired by mussels,and a hydrogel coating material was designed and prepared which was easy to be coated in a large area.Like ordinary coatings,there is no need for any chemical pretreatment of the substrate before use,just the preparation of the polymer solution system is coated on the substrate,and then dried to absorb water to obtain a hydrogel coating.In this process,catechol functional groups form a firm adhesion with the substrate through hydrogen bonding and other interactions.This method enables the hydrogel coating to adhere firmly to the substrate underwater,while the hydrogel surface is underwater superoleophobicity due to the hydration of the hydrophilic chain segment.Based on the migration orientation mechanism of hydrophilic and hydrophobic segments induced by the solvent replacement process,a series of amphiphilic polyurethane systems were designed and prepared to simultaneously achieve the superoleophobic properties of polyurethane hydrogel coating surface and strong underwater adhesion between various substrates.When the mixture of the amphiphilic polyurethane and water-soluble solvent is immersed in the water,the hydrophobic chain segments are directional migration and accumulation to the surface of the substrate through a chain segment orientation mechanism is triggered by the solvent and the water displacement effect,which prevents water molecules from entering the gap between the hydrogel coating and the substrate,and protects various interface adhesion between hydrogel coating and the substrate.At the same time,the hydrophilic chain segment migrates to the surface of the coating,and the hydration between water molecules endows the substrate surface with underwater superoleophobicity...