Marine antifouling coating based on modified polyurethane and halloweite nanotubes for slow-release of chlorgentianol alcohol

The problem of marine biological pollution seriously restricts the sustainable development of the shipping industry. In response to this technical challenge, this study innovatively developed a composite coating system (HFSiPU) based on the synergistic effect of the dual antifouling mechanism. The system first used molecular encapsulation technology to load the synthesized chlorgentianol alcohol (CHBA) into halloysite nanotubes (HNT), constructing nanoparticles (CHBA@HNT) with a static antifouling function enabled by controlled-release antifoulant. The unique tubular structure of HNT endows the material with an excellent CHBA loading capacity of up to 15 wt%. Meanwhile, a hydrophobic polyurethane (FSiPU) matrix, prepared through the synergistic modification strategy of organofluorosilicon, achieved long-term antifouling through its dynamic surface properties. Experimental results revealed that the daily release rate of CHBA@HNT in the composite coating system remained stable at 6.0 μg/cm² for more than 31 days. The modified FSiPU exhibited significantly enhanced hydrophobicity, with a water contact angle of 115° (a 42% increase) and a reduced surface free energy to 18 mJ/m² (a 63% decrease) compared to conventional polyurethane. In antifouling performance evaluations, the HFSiPU coating demonstrated excellent inhibitory effects against typical Escherichia coli, Staphylococcus aureus, as well as marine bacteria and algae, with biofilm adhesion inhibition rates remaining above 90% for all tested organisms. This research provides innovative insight and technical pathways for the development of a new generation of intelligent ship protection materials by effectively integrating static controlled-release and dynamic surface antifouling mechanisms.