Healable polymer coatings
Optimizing polymer self-healing through supramolecular interactions
Self-healing or healable polymers are macromolecular materials in which defects either heal autonomously or heal in response to an external stimulus. This behavior, which mimics Nature’s tissues ability to repair damage and to restore the original properties as well as functions, is technologically useful, as it extends the lifetime, increases the reliability, and improves the performance of many products. It has been demonstrated that defects in any thermoplastic polymer can, in principle, be healed, if two fractured surfaces are brought in contact above the material’s glass transition or melting temperature. However, the process is generally slow because the rates of chain diffusion and re-entanglement of polymer chains are inversely proportional to the length of the macromolecules. Several approaches have been proposed to overcome this problem, including the use of reversible bonds. These motifs reversibly dissociate at elevated temperatures or upon exposure to another suitable stimulus and this temporarily reduces the molecular weight and thus increases the healing rate and efficiency. When the stimulus is removed, the bonds re-form and the original properties are restored. This project explores approaches based on such materials to enhance the self-healing properties of polymeric materials.