Self-Healing Composite Materials: A Review on Preceding and Perspective Research

Abstract

With the need of increasing demand for enhancing the properties of composite materials to be used in different applications such as structural, aerospace, automobile, coating etc, the bio-inspired self-healing materials have been developed with the purpose of repairing themselves under damage caused by mechanical usage over time. These materials are bio-inspired (ex: healing of human skin) and designed on the basis of two different strategies: (a) release of healing agent into the cracks and (b) reversible cross links. This review paper comprehensively discusses the different methods (or approaches) of self healing mechanism in composite materials which is used to alleviate the effect of damage and to restore mechanical properties. Generally, two different self healing approaches are used (a) Extrinsic and (b) Intrinsic. Extrinsic utilizes the release of healing agents from the container ( i.e. Hollow glass tubes, Capsules, micro-vascular) which ruptures once crack propagates inside the material while Intrinsic utilizes the phenomena of reverse polymerization which triggers under external stimuli such as heat, light etc. On the basis of review result, it was found that the given methods and approaches used in self-healing have the potential of restoring mechanical properties by repairing the cracks. It was concluded that HGFs and Capsule based healing mechanism are suitable for small cracks repair while vascular mechanism are more likely to be used for larger cracks. Moreover, integrating sensors and actuators into the current self-healing mechanism would enhance the healing potential and attracts a future study.