Inducing mechanical self-healing in glassy polymer melts

Glassy polymer melts such as the plastics used in pipes, structural materials, and medical devices are ubiquitous in daily life. They accumulate damage over time due to their use, which limits their functionalities and demands periodic replacement. The resulting economic and social burden could be mitigated by the design of self-healing mechanisms that expand the lifespan of materials. However, the characteristic low molecular mobility in glassy polymer melts intrinsically limits the design of self-healing behavior. We demonstrate through numerical simulations that controlled oscillatory deformations enhance the local molecular mobility of glassy polymers without compromising their structural or mechanical stability. We apply this principle to increase the molecular mobility around the surface of a crack, inducing fracture repair and recovering the mechanical properties of the pristine material. Our findings establish a general physical mechanism of self-healing in glasses that may inspire the design and processing of new glassy materials.