Work

Sharkskin-inspired armour design: A facile powder-coating strategy for durable superhydrophobic surfaces in underwater applications

Year: 2025

Type: article

Abstract: Underwater superhydrophobic surfaces (SHS) hold great potential for various applications, but their development has been hindered by complex fabrication and limited durability. This study reported the first demonstration of a sharkskin-inspired SHS that combined micro-riblet armouring with a one-step powder-coating strategy to form a volumetric superhydrophobic (SH) layer. Here, polydimethylsiloxane (PDMS)-functionalized fumed silica nanoparticles were directly embedded into a partially cured polyurethane (PU)/PDMS composite sharkskin microstructure, creating a robust, hierarchical interface. This bio-inspired design produced two unprecedented features: (i) a regenerative volumetric SH layer with water contact angle (WCA) of 161°, where nanoparticles were anchored into the thickness of the coating to a certain depth rather than merely on the surface, and (ii) a riblet-based armoured framework that physically shielded nanoscale features from abrasion and hydrodynamic erosion, sustaining hydrophobicity. As a result, the coating exhibited exceptional durability, retaining SH properties after 24 m of sandpaper abrasion, 30 days of saltwater immersion, outdoor exposure, or a 25-min water jet test. The surface further achieved a 34 % drag reduction, outperforming conventional SH coatings. This environmentally friendly, solvent-free, single-step, and scalable approach overcomes long-standing durability limitations of SH sharkskin surfaces and provides a practical platform for large-scale maritime, industrial, and underwater applications. • A novel facile approach for underwater use durable superhydrophobic surface (SHS). • The SHS featured elastic micro-riblet ‘armour’ design with regenerative SH layer. • The SHS endured 24 m abrasion (3.3 kPa load), over 30 days in saltwater/outdoor. • The SHS exhibited 34 % drag reduction and strong antifouling against bacteria.

Source: Progress in Organic Coatings

DOI: 10.1016/j.porgcoat.2025.109841