A dolphin skin-inspired hydrogel fiber-based drag-reducing slippery coating for marine antifouling

Abstract

Based on the simulation of three key biological features related to dolphin skin, namely the subcutaneous papilla structure, the natural hydrogel collagen in papilla space, and the metabolic renewal function of the mucus layer, we designed a dolphin skin-inspired hydrogel fiber-based drag-reducing slippery coating (DIHSC) for marine antifouling. It was revealed that water-absorbing fibers could form hydrogel films on the surface of DIHSC after absorbing water and swelling. The increase in the coverage degree of water-absorbing fibers caused by the enhancement in the implantation density led to the reduction in the frictional resistance of the hydrogel film, making the surface much smoother. Static immersion and dynamic scouring experiments showed that fibers had stable fixation, while the experiment on marine microalgae indicated that DIHSC had excellent marine antifouling performance. We successfully obtained a smooth drag-reducing hydrogel surface by implanting water-absorbing fibers using the electrostatic injection technology, which effectively imitated the smoothness and low frictional resistance of the dolphin surface and metabolic renewal behaviors of the mucus layer, realizing long-term marine antifouling performance. This study promotes the application of bionic hydrogels in marine antifouling aspects.