Photosynthesis-Inspired Dual-Mode Self-Healing Coatings: Leveraging Peony-like ZnO for Corrosion Interception and Energy Harvesting

Abstract

Corrosion degradation has a significant impact on metallic materials' service life, posing critical environmental, safety and related challenges. Inspired by the energydriven self-healing mechanism of photosynthesis, silane-modified cellulose nanofibers (KMC) and polydopamine (PDA)-functionalized peony-like ZnO (PFZ) are integrated into a vitrimer matrix (PFD) to construct a composite coating on Q235 carbon steel, which is capable of spontaneous healing without artificial intervention.As a photothermal conversion trigger agent, PFZ can autonomously regulate its selfhealing performance according to the energy storage status of coating, toggling between "conservative" and "activated" modes to exhibit dual-mode self-healing behavior. This intelligent adjustment mechanism realizes the efficient utilization of solar energy and fully demonstrates superior environmental adaptability and selfhealing ability (crack narrowing within 10 s). In addition, PFZ also exhibits a unique "multilayered trapping effect" that effectively traps corrosive medium, permanently impeding their further diffusion behaviors. The enhanced barrier protection grants the coating an ultra-low current density (7.655×10 -10 A/cm 2 ) and corrosion rate (8.899×10 -6 mm/y), which are four and three orders of magnitude lower than those of Q235, respectively, representing excellent anti-corrosion performance. This bioinspired approach offers a promising strategy for developing advanced coatings with sustainable and efficient corrosion protection.