There is an ever-growing number of developments that aim to bring novel functionalities to polymer-coating systems with nanotechnology being one of them. This article will cover recent advances in the field of smart polymeric structures that are used in protective coatings in terms of stimulus and response, sensing mechanisms, and current or potential applications. Such structures are commonly based on polymers modified through organic or inorganic additives. Emphasis is placed on smart sensors used for detecting the onset of corrosion on polymer coated ferrous and nonferrous substrates. Examples of self-healing and repair through the action of microcapsules are also presented. (c) 2007 Wiley Periodicals, Inc.