PDMS@SiO2 surface modified superhydrophobic melamine sponges for enhanced drag reduction

Ocean vehicles, integral to ocean engineering, require reducing operational resistance, which is crucial. This study focuses on the modification of the surface of melamine sponge (PDMS@SiO₂) utilizing sol-gel methodology and dip coating technology, resulting in the successful fabrication of a resistance-reducing material characterized by superhydrophobicity and exceptional impact resistance. The study shows that the modified sponge has excellent superhydrophobic properties due to its controlled surface microstructure and chemical composition, with a contact angle of 160.1°. In simulated environments involving adhesion, sand impact, and durability in strong acid/alkali environments, the modified sponge maintained a water contact angle (WCA) of 130° for 24 h, representing a 19 % decrease from the initial value. Furthermore, cyclic compression tests revealed that the combination of PDMS and SiO₂ significantly improved the stability and fatigue resistance of the material, resulting in a reduction of stress attenuation from 43.9 % to 30.4 %. Additional rheometer and pipeline test results corroborated the substantial advantages of the modified sponge in minimizing fluid resistance and sustaining flow stability, with resistance reductions of up to 81 % and 60 %, respectively. This study demonstrates that the PDMS@SiO₂ modified melamine sponge has significant practical application value in reducing fluid resistance and prolonging laminar flow conditions underwater.