Advances in emerging hydrogel fouling-release coatings for marine applications

The accumulation of microorganisms, algae, mussels, and barnacles on the hull of sea vessels leads to biofouling, surface corrosion, and increased drag as the vessel moves through water costing the marine industry around $15 billion/year. Current commercial traditional antifouling coatings suffer from reduced energy efficiency and short lifespan and contain heavy metals that are toxic to marine organisms and humans. The banning of these coatings is due to environmental concerns, and nonbiocidal alternatives such as polymer-based coatings are being sought after. This review demonstrates emerging promises of hydrogel fouling-release coatings (FRCs) in the marine environment that may be effective against a prevalent amount of biofouling agents. The review also highlights the importance of polymer backbone materials with surface wettability characteristics possessing hydrophobic, hydrophilic, and zwitterionic properties and further discusses emerging antifouling techniques, synthesis of hydrogel, swelling behavior of hydrogel, laboratory assays of hydrogel coating, marine field test, and outlook of hydrogel fouling-release (FRCs) coatings.