A novel strategy to synthesize a glycerol-hydrogel with high stretchability, ultra-toughness, remarkable tolerance, and outstanding self-healing capability has been developed. A soft actuator has been fabricated based on the glycerol-hydrogel.

Biomimetic human skinlike materials with preferably self-healing ability, high sensitivity for external stimuli, and good adhesiveness against diverse substrates under a wide range of temperatures are of great importance in various applications such as wearable devices, human-motion devices, and soft robotics. However, most of the reported biomimetic human skinlike materials lack memory function, i.e., they cannot memorize the external stimuli once the stimuli disappear. This drawback hinders their applications in mimicking the human skin in real world. Here, a polyacrylamide/Au@polydopamine glycerol–water (GW) hydrogel has been designed to address this challenge. The as-prepared GW hydrogel exhibits a fast self-healing efficiency and good adhesiveness against diverse substrates under a wide range of temperatures (from −15 to 37 °C). Additionally, our GW hydrogel also possesses good perceived ability for external stimuli and subtle/large human motions. Most importantly, resistance memory function has been realized based on our GW hydrogel. These outstanding properties make it potentially significant in mimicking the human skin in real world.

Designing hydrogels with both excellent mechanical property and self-healing ability has attracted enormous attentions because applications of hydrogels are restricted in many fields due to their poor mechanical property and...

A self-healable poly(acrylic acid-co-maleic acid) hydrogel at low temperature with excellent mechanical properties and water retention was fabricated.

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.

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Thermo-responsive hydrogel is an important smart material. However, its slow thermal response rate limits the scope of its applications. Boron nitride nanosheet-reinforced thermos-responsive hydrogels, which can be controlled by heating, were fabricated by in situ polymerization of N-isopropylacrylamide in the presence of boron nitride nanosheets. The hydrogels exhibit excellent thermo-responsiveness and much enhanced thermal response rate than that of pure poly(N-isopropylacrylamide) hydrogels. Interestingly, the hydrogels can be driven to move in aqueous solution by heating. Importantly, the composite hydrogel is hydrophilic at a temperature below lower critical solution temperature (LCST), while it is hydrophobic at a temperature above LCST. Therefore, it can be used for quick absorption and release of dyes and oils from water. All these properties demonstrate the potential of hydrogel composites for water purification and treatment.

Boroxine-based thermosets with remarkable mechanical tunability, self-healing ability, recyclability, and adhesive strength are of significant importance in various applications. However, complex multistep reactions are often required to prepare such thermosets. Herein, a facile one-pot approach to synthesize boroxine-based malleable thermosets is proposed. Random copolymers with pendant boronic acid groups were synthesized from alkenyl monomers containing boronic acids [4-vinylphenylboronic acid (4-VPBA), 3-vinylphenylboronic acid, or 3acrylamidophenylboronic acid] and octadecanoxy polyethylene glycol methacrylate. Then, the as-prepared copolymers were cured to form thermosets with boroxine bonds. The tensile strengths of the thermosets were tailored to range from 9.3 to 27.5 MPa by increasing the concentration of 4-VPBA. Moreover, because of the reversible nature of dynamic boroxine bonds (transformation between boroxines and boronic acids) induced by water, the thermosets exhibit remarkable self-healing efficiency (up to 99%), tunable mechanical properties, and excellent recyclability. Additionally, the thermosets also demonstrate superior adhesive strength (as high as 73.9 MPa) on different substrates.