Organic composite coatings containing mesoporous silica particles: Degradation of the SiO2 leading to self-healing of the delaminated interface

Abstract

Mesoporous SiO2 is of interest as nano-container for storing active agents for corrosion inhibition or self-healing. However, the potential of mesoporous SiO2 itself for providing active corrosion protection so far was widely ignored. Here, SiO2 containing PVB coatings applied on zinc is shown to inhibit corrosion-driven organic coating disbondment and even to self-heal the already delaminated interface. The protection mechanism is that mesoporous SiO2 will degrade in the high alkaline pH at the delaminated area and forms a silicate layer that blocks underfilm corrosion and even re-establishes a protective and delamination resistant interface.