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This paper reviews the self‐stratifying coatings concept, which is a tool to formulate film‐forming compositions based on incompatible polymer blends capable of producing coatings having polymer/polymer composite structures and outstanding performance in a number of application fields. The self‐stratifying concept is applicable to waterborne, solvent‐based and powder coatings, requiring specific formulations and frequently also conditions of application and film formation. Micro‐heterogeneous and non‐homogeneous‐in‐layer (or ultimately double‐layer) film structures obtained by one‐coat application of a single coating composition render considerable enhancement in coatings properties (mechanical, protective etc.) particularly various surface/interfacial properties (e.g. scratch‐resistance, mar‐resistance and adhesion durability, etc.).

Recent developments indicate that the polymer coatings used to protect steel structures from corrosive environments are rarely one‐component systems. Polymeric blends used to protect the structures are a mixture of at least two polymers or copolymers. The heterophase polymer blends are known as polymer‐polymer composites (PPC). The advantages of PPC coatings in comparison to multicoat systems are high thickness per coat, excellent protection and superior layer adhesion. Presents a study in which a poly (epoxy‐chlorinated rubber‐silicone) PPC coating was prepared and its chemical resistance properties in acid, alkali and neutral solutions were studied. Different combinations of these three binders were also prepared in toluene:acetone solvent mixture and the chemical resistance properties of these PPCs were evaluated in comparison with the corresponding multicoat system with the same thickness. Finds that the PPCs show superior properties when compared to multicoat systems. Studies the electrochemical behaviour such as potential, resistance and capacitance of the PPCs and the multicoat systems on steel substrate in sodium chloride solution and finds that the PPCs have higher resistance value than the multicoat systems. Based on the experimental results, concludes that a single coat of PPC can be recommended for protecting the steel structures from chemical and marine environments, instead of using conventional three‐ or four‐coat systems based on the same or different film formers.