Chirality-induced dual self-healing chitosan-based coating on titanium surface for corrosion protection.

The development of self-healing anti-corrosion coatings has recently garnered significant attention as an efficient strategy for preventing substrate corrosion and prolonging substrate service life. Herein, we develop a chirality-induced dual self-healing coating through pH-responsive tryptophan isomers-loaded halloysite nanotubes (L/D-Trp@HNTs) imbedded into chitosan (CHI) coatings. Results showed that the L/D-Trp@HNTs/CHI coating exhibited an excellent self-healing behavior, which can originate from the release of L/D-Trp from the HNTs nanocontainers. The protection effect of the coating was effectively enhanced by two approaches. First, L-Trp could be released from the HNTs and then mainly permeates through the CHI coating, forming a protective film on the metal surface. Second, D-Trp released from the nanocontainers could be captured by the CHI coating through the formation of H-bonds, significantly increasing the crosslinking density of the CHI coating and reducing defects in the CHI coating. This natural polysaccharide CHI-based chiral system could open a new avenue toward corrosion protection applications.