Biomimetic carbon nanotube networks with pH-gated Ce3+ for sustained corrosion protection

A vascular-inspired CNT-based system was developed for self-healing corrosion protection. • pH-triggered PDA shell rupture enables controlled Ce 3+ release at corrosion sites. • DA and Ce 3+ synergistically suppress corrosion on metal surfaces. • Network structure reinforces tensile strength and elongation of epoxy matrix. Metal corrosion threatens public safety and assets. Here, we developed a vascular-inspired carbon nanotube (CNT) epoxy coating (PDA@Ce-CNT/EP) that couples pH-triggered inhibitor release with preferential migration to extend protection. Ce 3+ was loaded into expanded CNT nanochannels by vacuum–air cycling and confined within a polydopamine (PDA) shell that exhibits pH-responsive permeability under corrosive conditions, while the CNT nanonetwork promotes localized release and enrichment of inhibitors at damaged regions. After 75 days of immersion in 3.5 wt% NaCl solution, the PDA@Ce-CNT/EP coating maintained a low-frequency impedance modulus of 9.44 × 10 10  Ω·cm 2 at 0.01 Hz, which remained significantly higher than that of neat EP under identical conditions. It also exhibited enhanced strength and toughness, with tensile strength increasing from 2.80 to 3.99 MPa and elongation at break rising from 38.23% to 50.38%. These improved properties stem from the synergy among Ce 3+ , the PDA shell, and the vascular-like CNT network, a system that simultaneously obstructs corrosive species penetration and promotes uniform stress distribution. This strategy integrates controlled and corrosion-responsive inhibitor release within a hierarchical CNT-based nanostructure, thereby enhancing localized self-healing corrosion protection and providing an alternative design concept for intelligent self-healing coating systems. Download: Download high-res image (408KB) Download: Download full-size image