“Elastic Matrix–Surface Microstructure–Mucus Lubrication” Multiscale Biomimetic Fish Scale Coating: Design and Application in Ship Drag Reduction

Under global energy transition and carbon reduction, enhancing ship energy efficiency requires breakthroughs beyond traditional drag reduction technologies. Addressing the issues of high energy consumption in gas lubrication, environmental risks posed by polymer additives, and the strong operational dependency of rigid biomimetic structures, this work was inspired by the joint action of a variety of drag reduction methods; “elastic matrix–surface microstructure–mucus lubrication” was put forward, and a multiscale biomimetic fish scale drag reduction coating (MCPU) was designed and fabricated. The elastic polyurethane matrix was constructed by cross-linking hydroxy-terminated trifluoropropyl methyl siloxane (HFPMOS) with isophorone diisocyanate (IPDI), mimicking the flexibility and energy dissipation characteristics of fish scales. Surface spraying of SiO2 nanoparticles formed a coffee-ring structure resembling fish-scale micronano structures. The coating was embedded with polyurethane microcapsules filled with silicone oil and impregnated with silicone oil to simulate the mucus of fish. MCPU achieved ship drag reduction through the joint action of multiple drag reduction mechanisms and demonstrated a drag reduction rate of 17.4% for a small boat model.