Mussel-Inspired Self-Healing Coatings Based on Polydopamine-Coated Nanocontainers for Corrosion Protection

Abstract

The mussel-inspired properties of dopamine have attracted immense scientific interest for surface modification of nanoparticles due to the high potential of dopamine functional groups to increase the adhesion of nanoparticles to flat surfaces. Here, we report for the first time a novel type of inhibitor-loaded nanocontainer using polydopamine (PDA) as a pH-sensitive gatekeeper for mesoporous silica nanoparticles (MSNs). The encapsulated inhibitor (benzotriazole) was loaded into MSNs at neutral pH, demonstrating fast release in an acidic environment. The self-healing effect of water-borne alkyd coatings doped with nanocontainers was achieved by both on-demand release of benzotriazole during the corrosion process and formation of the complexes between the dopamine functional groups and iron oxides, thus providing dual self-healing protection for the mild steel substrate. The coatings were characterized by electrochemical impedance spectroscopy, visual observations, and confocal Raman microscopy. In all cases, the coatings with embedded benzotriazole-loaded MSNs with PDA-decorated outer surfaces demonstrated superior self-healing effects on the damaged areas. We anticipate that dopamine-based multifunctional gatekeepers can find application potential not only in intelligent self-healing anticorrosive coatings but also in drug delivery, antimicrobial protection, and other fields.

Sunlight‐Activated Self‐Healing Polymer Coatings

“…The released healing chemistry then repairs the damage. In coatings, self‐healing has been achieved with micro‐ and nanocapsules containing core materials such as linseed oil, polydimethylsiloxanes (PDMSs), polyurethanes (PUs), or silyl esters . Scribe damage to the coating exposes the substrate, ruptures the capsules, and releases the healing material.…”

“…Behzadnasab et al showed that larger capsules can lead to better healing performance through visual inspection of the coatings. Qian et al used a bioinspired healing system to prevent corrosion and provide the sustained release of the healing agent . Cho et al incorporated a two‐part (poly)dimethyl siloxane (PDMS)‐based healing chemistry in polymer microcapsules .…”

“…In coatings, selfhealing has been achieved with micro-and nanocapsules containing core materials such as linseed oil, polydimethylsiloxanes (PDMSs), polyurethanes (PUs), or silyl esters. [11][12][13][14][15][16][17][18][19][20] Scribe damage to the coating exposes the substrate, ruptures the capsules, and releases the healing material. Behzadnasab et al showed that larger capsules can lead to better healing performance through visual inspection of the coatings.…”

“…Qian et al used a bioinspired healing system to prevent corrosion and provide the sustained release of the healing agent. [12] Cho et al incorporated a two-part (poly)dimethyl siloxane (PDMS)-based healing chemistry in polymer microcapsules. [14] The ruptured microcapsules healed the damage with added heat.…”

Electrospun Multiple-Chamber Nanostructure and Its Potential Self-Healing Applications

“…Considering the coincide of the characteristic peaks of PAN and epoxy resin, and the few amounts of epoxy and triethylenetetramine, the characteristic peaks of the two healing agents in the core-shell fibers IR was not obvious. PAN, as a good container [ 50 , 51 , 52 ] in encapsulating the two reactive healing agents, will be further judged by thermal stability.…”