Fabrication of Poly(acrylic acid)/Boron Nitride Composite Hydrogels with Excellent Mechanical Properties and Rapid Self-Healing Through Hierarchically Physical Interactions

Abstract

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 B0.5P70 (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.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2800-2) contains supplementary material, which is available to authorized users.

Boron Nitride Nanosheets Strengthened PVA/Borax Hydrogels with Highly Efficient Self‐Healing and Rapid pH‐Driven Shape Memory Effect

“…As shown in Figure a, the band at 3602 cm −1 ascribed to the stretching vibration of ─OH of PVA/borax hydrogel, while it shifted to 3531 cm −1 in PVA/BNNS‐NH 2 composite hydrogel, illustrating that the hydrogen bonds were built between BNNS‐NH 2 and PVA chains. [ 1,8 ] The dynamic borate bonds in PVA/borax hydrogels and PVA/BNNS‐NH 2 composite hydrogels were revealed by the peak at 1415 and 1400 cm −1 , respectively, assigned to asymmetric stretching of B─O─C. [ 23,24 ] The shifting further confirmed the establishment of hydrogen bonds.…”

“…Among them, the self‐healing hydrogels attracted numerous attentions ascribing the unexceptionable biocompatibility, water‐holding capacity, and the hydrophilicity. [ 1–4 ] Over the past decades, self‐healing hydrogels have been developed through main strategies including encapsulation of healing agents [ 5–7 ] and introduction of dynamic bonds. [ 8 ] Although the strategy of introducing the microcapsules equipped with healing agents accomplishing the self‐healing process, the number of self‐healing times is limited and the external stimulation is required.…”

“…exploited the novel poly(acrylic acid) (PAA)/BNNS composite hydrogels exhibiting excellent tensile strength, stiffness, and toughness which was much higher than those of PAA hydrogel. [ 1 ] Wang et al. reported a class of mechanically robust, ultrastretchable, and thermal‐conducting composite hydrogels by in situ polymerizing acrylamide monomers in the presence of vinyl‐functionalized boron nitride nanosheets.…”

2D boron nitride nanosheets for polymer composite materials

“…As a result, the maximum amount of load transfer could be achieved at the interphases with the lowest amount of BNNSs loading. For example, Young's modulus and tensile strength of polyacrylic acid (PAA) hydrogel (water content 70 wt.%) composites were increased by 244% and 57%, respectively, when 0.5 g L −1 BNNSs was added to the PAA hydrogel 112 . This excellent reinforcement 49,67,81,92,102,105,[108][109][110]112,113,132,140,152,156,183,233,236,[245][246][247][248][249] .…”

Self‐Healable and Conductive Double‐Network Hydrogels with Bioactive Properties

“…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. [ 5 ] Tao et al. exploited carbon nanotube‐doped electrically conductive hydrogels for the first time.…”