Emulsion-Based Organohydrogels with Switchable Wettability and Underwater Adhesion toward Durable and Ecofriendly Marine Antifouling Coatings

Marine biofouling has become an extensive problem, resulting in severe harm to marine facilities and maritime operations. Extensive efforts have been carried out to develop effective antifouling strategies for practical applications. Nevertheless, durable and renewable antifouling surfaces with broad-spectrum fouling resistance are in pressing need. Here, antifouling charged organohydrogels (COHGs) possessing amphiphilic and zwitterionic heteronetworks are fabricated by facile emulsion polymerization. The synergistic collaboration of covalent linkages, electrostatic interaction, and hydrogen bonding endow the COHGs with excellent mechanical properties, including stretchability, compressibility, and recoverability. Owing to the spatial restraints between hydrophilic and oleophilic chains in interpenetrating heteronetworks, the COHGs exhibited significantly low-swellable behavior whether in water or in oil, beneficial to durable applications without impairment of intrinsic performances. The amphiphilic heteronetworks could experience structure rearrangement in response to the surrounding solvents (water or hexadecane), leading to switchable surface wettability. Moreover, the COHGs possess strong wet adhesion to various organic and inorganic surfaces due to synergetic interactions existing at the interface between COHGs and operational substrates, including the hydrophobic effect, electrostatic interaction, and nonswelling behavior, which greatly avoid tedious operation processes during practical application. As for the relationships between the structure and antifouling performances, the elastic surfaces combined with amphiphilic and zwitterionic features reveal remarkable fouling resistance (Navicula sp. and Dunaliella tertiolecta) and recyclable utilization. The COHGs may provide an approach to develop high-performance and ecofriendly antifouling materials.