Advances in smart coatings: classification, improvements and applications

The concept of intelligence has many applications, such as coating and cyber security. Smart coatings have the ability to sense, response to several cycles and interact with their environment. Properties that are affected by either momentary or continuous external stimuli in smart coatings can be related to corrosion, fouling, fungal, self-healing, piezoelectric, microbiological, etc. These coating properties can be obtained via combinations of either organic or inorganic polymer phases, additives and pigments. In this study, a review on smart coatings with corrosion protective properties is reported from two aspects of intrinsic and extrinsic self-healing ability. The concept of extrinsic self-healing smart anticorrosive coatings is based on the use of capsules or multichannel vascular systems loaded with amount of healing agent/inhibitor. On the other hand, the idea of intrinsic self-healing ability relies on the chemical and physical structure of polymer matrix that under the stimulation of heat, light, and other external stimuli, the reactions among polymer chains are easily triggered. The outcome is that smart coatings exhibit improved properties compare to traditional coatings. It is mentioned that smart anticorrosive coating not only has enhanced passive barrier function, but also realizes active defense. As a result, there is a significant improvement of the service life and overall performance of the coating.