A Highly Stretchable and Autonomous Self-Healing Polymer Based on Combination of Pt•••Pt and π-π Interactions

A new self-healing polymer has been obtained by incorporating a cyclometalated platinum(II) complex Pt((CNN)-N-perpendicular to-N-perpendicular to)Cl ((CNN)-N-perpendicular to-N-perpendicular to = 6-phenyl-2,2-bipyridyl) into a polydimethylsiloxane (PDMS) backbone. The molecular interactions (a combination of PtPt and - interactions) between cyclometalated platinum(II) complexes are strong enough to crosslink the linear PDMS polymer chains into an elastic film. The as prepared polymer can be stretched to over 20 times of its original length. When damaged, the polymer can be healed at room temperature without any healants or external stimuli. Moreover, the self-healing is insensitive to surface aging. This work represents the first example where the attractive metallophilic interactions are utilized to design self-healing materials. Moreover, our results suggest that the stretchability and self-healing properties can be obtained simultaneously without any conflict by optimizing the strength of crosslinking interactions.