A novel strategy for constructing active anti-corrosive coatings by embedding three-dimensional fiber networks

摘要

The corrosion protection effectiveness of micro/nanocontainers -based intelligent coatings is significantly affected by the dispersion of these micro/nanocontainers throughout the coating matrix. Inspiration by the bionics idea of a ‘vascular network’, a polylactic acid (PLA) three -dimensional fiber network incorporated with different concentrations (1 wt.%, 2 wt.%, and 3 wt.%) of pH - responsive titanium dioxide-8-hydroxyquinoline (TiO2-8HQ) nanotubes are designed on the Mg alloy surface using the electrospinning technology. The electrospun TiO 2- 8HQ@PLA network is crosslinked and evenly dispersed on the surface, which is also sensitive to the local pH variations. The encapsulated 8HQ inhibitors can transport through the three-dimensional fiber network and promise to realize the continuous and effective self -healing effects on the multi -defect areas on the coating surface. Afterward, an epoxy coating is performed on the surface, which permeates through the inner network and forms a kind of vascular network intelligent coating. The corrosion protection and self -healing performance of these coatings are assessed through the electrochemical test and surface analysis. Results reveal that th e embedded TiO 2- 8HQ@PLA three-dimensional network significantly improves the corrosion resistance and self -healing performance of the coatings. Especially, 2%TiO2-8HQ@PLA-EP demonstrates the most enduring corrosion resistance over 50 days of immersion in a 3.5 wt.% NaCl solution, with the coating resistance and charge transfer resistance values of 2.33 × 10 6 Ω·cm2 and 4.81 × 10 6 Ω·cm2, respectively. Additionally, the crosslinked three-dimensional fiber network enhances the adhesion strength ( 38.01 MPa) and surface wettability (104.25° ± 0.15° ), which greatly strengthens the physical barrier performanc e, which is capable of sustaining long-term serving life in an aggressive environment. The combination of the micro/nanocontainers technology and vascular network innovative design provides a unique insight into active corrosion control on diverse metals.