Crack healing in polymeric materials via photochemical [2+2] cycloaddition

Photochemical crack healing in a polymeric material was accomplished by employing a tricinnamate monomer. A cross-linked network was obtained via [2 + 2] photocycloaddition of the monomer, and the resulting cyclobutane cross-links reversed to the original cinnamoyl groups upon crack formation. Crack healing was achieved via re-photocycloaddition of cinnamoyl groups.