Rapid Self-healing and Strong Adhesive Elastomer via Supramolecular Aggregates from Core-shell Micelles of Silicon Hydroxyl-functionalized cis-Polybutadiene

Liquid trimethoxy silane-functionalized cis-polybutadiene ( cis -PB-Si(OMe) 3 ), possessing number-average molecular weights of cis -PB segments ( M n,PB ) ranging from 1800 g/mol to 5400 g/mol, with cis -1,4 content of ca. 80% and high functionality (>96%) could be synthesized by coordination copolymerization of living cis -PB chain ends with ethenyltrimethoxy-silane with neodymium-based catalytic system. The silicon hydroxyl-functionalized cis-polybutadiene ( cis -PB-Si(OH) 3 )-based micelles in water have been achieved by in situ hydrolysis of cis -PB-Si(OMe) 3 in hexane/water mixture (pH=6.8) at 70 °C and by sequential removal of residue hexane. The size of the above micelles with soft elastic cis -PB cores could be remarkably enlarged by loading SiO 2 nanoparticles on their surfaces via hydrogen bonding interaction. Giant supramolecular long chain aggregates or networks formed by hydrogen bonding interaction and possible O—Si—O chemical bonds between cis -PB-Si(OH) 3 -based micellar surfaces had relatively large size and thus precipitated from water after several months of storage, leading to production of cis -PB-Si(OH) 3 solid elastomer with extremely low T g at −107.0 °C. The left cis -PB-Si(OH) 3 -based micelles in water with relatively small size gradually formed the water-insoluble cis -PB-Si(OH) 3 -based supramolecular aggregates or networks. The cis -PB-Si(OH) 3 -based supramolecular elastomer exhibited excellent self-healing property within 60 s at 25 °C. The elastomer (20 mg) in a joint of 25 mm × 30 mm (2.7 mg/cm 2 ) provided very strong adhesion for two pieces of glass and the bound glass keep unchanged at room temperature for 98 h even hung with 100 g of steel column below. The cis -PB-Si(OH) 3 -based supramolecular elastomer would have potential applications in adhesives, self-healing materials, damping materials and elastic materials.