Hollow mesoporous zirconia nanocontainers for storing and controlled releasing of corrosion inhibitors

Release of inhibitor molecules on demand from nanocontainers dispersed in a passive barrier coatings offer great promise for active corrosion protection coatings of metals and alloys with self healing ability. In the present study, hollow mesoporous zirconia nanospheres (hm-ZrO2) with a hollow core/porous shell structure are proposed as effective containers for corrosion inhibitor loading and releasing. Hollow mesoporous zirconia nanocontainers were synthesized using solid silica nanoparticles as templates. The morphology and phase of zirconia nanocontainers were studied using high resolution transmission electron microscopy and laser Raman spectroscopy. 2-Mercaptobenzothiazole was selected as the model corrosion inhibitor for the encapsulation. The storage and release properties of hm-ZrO2 were investigated using UV–visible spectroscopy. The encapsulation efficiency of hm-ZrO2 was 63% and we observed a faster and higher release of 2-MBT from hm-ZrO2 when the pH was shifted from neutral value.