A robust superhydrophobic silica@halloysite modified perhydropolysilazane coating for marine antifouling

The attachment of fouling organisms in marine environments poses serious challenges to the service life and energy efficiency of underwater structures. Traditional antifouling coatings, plagued by environmental pollution, fall short of green and sustainable development goals. To address this, this study develops an eco-friendly multifunctional antifouling coating based on perhydropolysilazane (PHPS) and hexadecyltrimethoxysilane-modified silica-coated halloysitenanotubes (HDTMS-SiO 2 @HNTs). The coating’s functionality is governed by two synergistic interfacial phenomena: the chemical reduction of surface free energy through the grafting of long-chain alkyl groups, and the physical amplification of roughness via a hierarchical micro/nano-structure derived from the tubular halloysite framework decorated with silica nanoparticles. The coating, prepared via a simple spray-coating process and thermal curing, exhibits a static water contact angle of 158° and sliding angle of ≈6°. This superhydrophobic state is characterized by the formation of a stable air cushion at the solid–liquid interface, effectively minimizing adhesion of marine foulants. At 5 wt% filler loading, the coating demonstrates robust adhesion (Grade 0), high hardness (6H), and excellent barrier properties (EIS). Furthermore, incorporation curcumin-loaded halloysitenanotubes (Cur@HNTs) yields > 99.99% bacterial reduction against both Escherichia coli and Staphylococcus aureus . This work provides a robust, fluorine-free surface engineering strategy for the design of durable marine antifouling coatings.