Fabrication of Poly(acrylic acid)/Boron Nitride Composite Hydrogels with Excellent Mechanical Properties and Rapid...

Many living tissues possess excellent mechanical properties and self-healing ability. To mimic these living tissues, a series of novel composite hydrogels, poly(acrylic acid)/surface-modified boron nitride nanosheets (PAA/BNNS-NH₂) were fabricated simply through hierarchically physical interactions: molecular-scale metal coordination interaction between -COOH of PAA and Fe³⁺ and nanoscale H-bond between -COOH of PAA and -NH₂ of BNNS-NH₂. The composite hydrogels exhibit both excellent mechanical properties (including enhanced fracture stress, elongation, toughness, Young's modulus, and dissipated energy) and rapid healing ability without any external stimulus. Especially, the B_0.5P₇₀ (the hydrogel with BNNS concentration of 0.5 mg mL^- 1, the water content of 70 wt%) exhibits a fracture stress of ~ 1311 kPa and toughness of ~ 4.7 MJ m^- 3, almost ~ 3 times and ~ 8 times to B₀P₇₀, respectively. The excellent properties, combined with the simple preparation method, endow these composite hydrogels with potential applications.