Azide/Alkyne-Click-Reactions of Encapsulated Reagents: Toward Self-Healing Materials

The successful encapsulation of reactive components for the azide/alkyne-click-reaction is reported featuring for the first time the use of a liquid polymer as reactive component. A liquid, azido-telechelic three-arm star poly(isobutylene) ((M) over bar (n) = 3900 g . mol(-1)) as well as trivalent alkynes were encapsulated into micron-sized capsules and embedded into a polymer-matrix (high-molecular weight poly(isobutylene), (M) over bar (n) = 250 000 g . mol(-1)). Using ((CuBr)-Br-I(PPh3)(3)) as catalyst for the azide/alkyne-click-reaction, crosslinking of the two components at 40 degrees C is observed within 380 min and as fast as 10 min at 80 degrees C. Significant recovery of the tensile storage modulus was observed in a material containing 10 wt.-% and accordingly 5 wt.-% capsules including the reactive components within 5 d at room temperature, thus proving a new concept for materials with self-healing properties.