New valve-free organosilica nanocontainer for active anticorrosion of polymer coatings

Abstract

Smart coatings with inhibitor loaded nanocontainers exhibit significant efficiency and durability in prolonging metal life-time and reducing catastrophic failure. However, scaling and further practical intelligent anticorrosion applications of such coatings are still greatly limited by time-consuming installation of various nanovalves. Herein, hybrid hollow mesoporous organosilica was obtained by facile selective etching and served as valve-free nanocontainer to prepare smart anticorrosive coatings. Intelligent functions for inhibitor release and coating active corrosion protection are executed by the cargo-framework interaction, which is sufficiently demonstrated by experimental and computational results. Specifically, inhibitor is encapsulated at neutral pH and released under acidic conditions, which can make nanocontainer spontaneously undergo the pH changes resulted from coating damage and corrosion onset, then respond quickly to achieve in situ repair of corrosion. Correspondingly, exposure of the coating sample containing loaded nanocontainer in NaCl solution shows negligible corrosion and exhibits an increase of Rc (from 606.1 kΩ cm2 to 2967 kΩ cm2) and Rct (from 244.1 kΩ cm2 to 1985.5 kΩ cm2) with the immersion time, while significant deterioration of controlled samples (Rct from 118.7 kΩ cm2 to 46.9 kΩ cm2 and from 5.22 kΩ cm2 to 1.93 kΩ cm2, respectively). Notably, this nature-gated approach will provide novel idea for the preparation of smart nano delivery system for smart anticorrosive coatings.