Nanocontainers: A comprehensive review on their application in the stimuli-responsive smart functional coatings

This review summarizes recent developments in nanocontainer-based smart functional coatings done during the last 15 years. These types of coatings were first developed by researchers at the Max Planck Institute of Colloids and Interfaces in the year 2006 under the supervision of Professor Mohwald. Since then, the nanocontainer-based smart anti-corrosion coatings have attracted the attention of researchers worldwide, as can be concluded from the number of publications (>1500 publications during the last decade). The concept of the nanocontainers loaded smart coatings has already been transferred to the level of commercialization. The primary aim of the review is to compile different researches that have been published to develop an in-depth understanding of the field and summarize various nanocontainers utilized, recent advancements in the field, and prospects related to the smart coating loaded with stimuli-responsive nanocontainers. This review also aims to provide extensive knowledge on the underlying phenomena and basic mechanisms that influence the loading and release of active ingredients in nanocontainers, hence controlling their design for application in multifunctional smart coatings. Herein, all the major class of nanocontainers utilized so far has been covered for the first time. It can be concluded by reviewing the literature that different nanocontainers have been exhibited: from polymeric material to inorganic mesoporous nanostructures. These smart nanocontainers have shown the sophisticated trigger mechanism of releasing their active ingredients into the passive host matrix of the coatings. The research on the industrial use of these smart coatings with several autonomic functionalities is now the primary emphasis. The hunt for novel forms of multifunctional nanocontainers with distinct triggering mechanisms continues, particularly for low-cost natural nanocontainers.