Self-Healing Polymeric Coatings: Beyond Scratch-Healing

Most polymeric coatings are susceptible to impairments induced by environmental degradation and mechanical damage, which eventually lead to loss of function or even macroscopic failure of the coating. With conventional coating technologies, repair of a coating is tedious and expensive. The use of self-healing coatings ¿ i.e., coatings that possess an intrinsic ability to heal damage ¿ can prolong the operational life of coatings and reduce the frequency of full coating replacement. This project will develop a generic platform technology that can repair not only minor surface scratches but also deep cracks, via a simultaneous crack closing and sealing process. The approach involves the use of a polymer composite coating that has a unique morphology at an ultrafine scale. In Phase I, a new self-healing polyurethane-based coating formulation, and a method of producing the same, was developed. The self-healing of surface scratches, as well as deep and narrow razor blade cracks, was demonstrated. In addition, the coating¿s high gloss was maintained after the self-healing of the crack or scratch occurred. Phase II will optimize the self-healing polyurethane nanocomposite system and implement the platform technology in various polymer matrices for different commercial applications. Additionally, environmentally-friendly solutions, including a zero VOC coating solution, will be developed. Commercial Applications and other Benefits as described by the awardee: The paint and coating industry represents a mature $50+ billion market worldwide. The proposed self-healing nanocomposite coating technology should have immense potential in OEM/product coating applications, in maintenance paints, and in marine and other special purpose coating applications. Reduction in the frequency of the repainting job not only would be cost-effective, but also would help the environment by reducing the consumption of raw materials and the emission of VOCs.