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Azide/Alkyne‐“Click”‐Reactions of Encapsulated Reagents: Toward Self‐Healing Materials

2011; Wiley; Volume: 32; Issue: 5 Linguagem: Inglês

10.1002/marc.201000687

1521-3927

Maria M. Gragert, Marlen Schunack, Wolfgang H. Binder,

Photochromic and Fluorescence Chemistry

Abstract 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) ( $\overline {M} _{{\rm 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), $\overline {M} _{{\rm n}} $ = 250 000 g · mol −1 ). Using (Cu I Br(PPh 3 ) 3 ) as catalyst for the azide/alkyne‐“click”‐reaction, crosslinking of the two components at 40 °C is observed within 380 min and as fast as 10 min at 80 °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. magnified image