Self-healing polymers and composites

There are a number of techniques for creating polymer shell walls that protect the reactive materials inside them. The most common methods involve forming a shell at the interface of droplets in an oil-in- water emulsion. It is also possible to incorporate the polymerizer as a latent ability in the matrix itself, as either a residual part of the matrix polymerization reaction, or one that results from an environmental stimulus. Unlike capsule-based systems, vascular networks receive the healing agent after the network is in place, usually by applying a vacuum. Additional connectivity, in two- or three-dimensional networks of channels, gives vascular systems numerous performance advantages. The network could be refilled and we found that the samples could be healed up to seven times. To increase the number of healing cycles, members of our group next placed healing agents and polymerizers in two isolated networks, which extended the number of healings to 16.