Synthesis of poly(acrylic acid)–Fe³⁺/gelatin/poly(vinyl alcohol) triple‐network supramolecular hydrogels with high toughness, high strength and self‐healing properties

Abstract

Hydrogels with good mechanical and self‐healing properties are of great importance for various applications. Poly(acrylic acid)–Fe3+/gelatin/poly(vinyl alcohol) (PAA‐Fe3+/Gelatin/PVA) triple‐network supramolecular hydrogels were synthesized by a simple one‐pot method of copolymerization, cooling and freezing/thawing. The PAA‐Fe3+/Gelatin/PVA triple‐network hydrogels exhibit superior toughness, strength and recovery capacity compared to single‐ and double‐network hydrogels. The mechanical properties of the synthesized hydrogels could be tailored by adjusting the compositions. The PAA‐Fe3+/Gelatin/PVA triple‐network hydrogel with 0.20 mmol Fe3+, 3% gelatin and 15% PVA could achieve good mechanical properties, the tensile strength and elongation at break being 239.6 kPa and 12.8 mm mm−1, respectively, and the compression strength reaching 16.7 MPa under a deformation of about 91.5%. The synthesized PAA‐Fe3+/Gelatin/PVA triple‐network hydrogels have good self‐healing properties owing to metal coordination between Fe3+ and carboxylic groups, hydrogen bonding between the gelatin chains and hydrogen bonding between the PVA chains. Healed PAA‐Fe3+(0.20)/Gelatin3%/PVA15% triple‐network hydrogels sustain a tensile strength of up to 231.4 kPa, which is around 96.6% of the tensile strength of the original samples. Therefore, the synthesized triple‐network supramolecular hydrogels would provide a new strategy for gel research and expand the potential for their application. © 2019 Society of Chemical Industry

Stretchable, Healable, and Degradable Soft Ionic Microdevices Based on Multifunctional Soaking-Toughened Dual-Dynamic-Network Organohydrogel Electrolytes

“…The tensile curves clearly showed that with the increasing self-healing time, the recovery degree of mechanical properties became higher, and the sample could be recovered almost entirely after 48 h of contact at RT (Figure 4C), which could be a synergic effect of metal migration and coordination, hydrogen bonding, and electrostatic interactions between the two polymer networks. 38 In addition, Figure 4D showed the healing of electrical conductivity after putting two separated pieces of gels together in which the conductivity could be rapidly recovered within seconds. Both the mechanical and electrical self-healing performance could satisfy the demand of fabricating self-healing stretchable devices, in which the healing could be accelerated with external heat activation according to previous literatures.…”

“…Both the mechanical and electrical self-healing performance could satisfy the demand of fabricating self-healing stretchable devices, in which the healing could be accelerated with external heat activation according to previous literatures. 7,38,41 Regarding the degradation performance, unlike single-network gelatin organohydrogel 7 or Fe 3+ -cross-linked PAA hydrogel 24 that could turn into the liquid state in DI water after a few days, the GEL/PAA-GL organohydrogels were found to be stable in water for at least 1 week owing to the stronger interactions between gelatin and PAA networks. However, by elevating the temperature or adding other reagents such as glycerol or sodium citrate to dissociate the metal ions from carboxyl groups, the degradation time of GEL/PAA-GL could be remarkably reduced.…”

Strong and tough, pH sensible, interpenetrating network hydrogels based on gelatin and poly(methacrylic acid)

“…At the same time, gelatin molecules were entrapped in the network of PMAA and, after cooling down to 4°C, formed physical cross‐links due to triple helices formation. [ 32 ] Water entrapped in the structure of hydrogels acted as a porogen, contributing to the high porosity of the hydrogels. The resulting materials were constituted from highly porous interpenetrating networks of covalently cross‐linked PMAA and physically cross‐linked gelatin.…”

Supramolecular ionic polymer/carbon nanotube composite hydrogels with enhanced electromechanical performance

“…Tensile tests of the composite hydrogels were conducted with reference to the ASTM D638 standard, with slight modification [45]. Uniaxial tensile tests on rectangular hydrogel strips (50 mm × 10 mm × 1.0 mm) were performed on an Instron 5567 universal testing machine at a crosshead speed of 10 mm/min.…”