Self‐Healing Polymers

Polymers with the ability to “self‐heal” in response to damage are highly sought after for applications in which damage is costly or difficult to detect/repair. Polymers that heal in response to manual application of external stimuli (heat) were first proposed. The success of self‐healing polymers is contingent on choosing a monomer/catalyst combination compliant to the healing mechanism. Both the stored monomer and catalyst must be compatible with the molding and processing conditions of the base polymer. This chapter describes the development of self‐healing polymers utilizing ring‐opening metathesis polymerization (ROMP) and cross‐metathesis (CM) processes. It discusses the modes of monomer storage and delivery to damage regions, catalyst stability, and the consequences of monomer and catalyst choice on self‐healing. The chapter also deals with the second‐generation self‐healing materials with intrinsic healing mechanisms in which metathesis catalysts are directly incorporated into the polymer structure.