A structural polymeric material with the ability to autonomically heal cracks
Structural polymers are susceptible to damage: cracks form deep within the structure where detection is difficult and repair is almost impossible. Damage in polymeric coatings, adhesives, microelectronic components, and structural composites can span many length scales. Structural composites subject to impact loading can sustain significant damage on centimeter length scales, which in turn can lead to subsurface millimeter scale delaminations and micron-scale matrix cracking. Coatings and microelectronic packaging components have cracks that initiate on even smaller scales. Once cracks have formed within polymeric materials, the integrity of the structure is significantly compromised.
Inspired by biological systems in which damage triggers a healing response, Scott White at the Beckman Institute at the University of Illinois developed a structural polymeric material with the ability to autonomically heal cracks. The incorporation of a microencapsulated healing agent and a catalytic chemical trigger within an epoxy matrix accomplished this healing process. An approaching crack ruptures embedded microcapsules, releasing healing agent into the crack plane through capillary action. Polymerization is triggered by contact with the embedded catalyst, bonding the crack faces.
Contact: University of Illinois Beckman Institute, Urbana, IL, USA.
For more information, see Transmaterial 2: A Catalog of Materials That Redefine our Physical Environment