A Facile Strategy for Synergistic Integration of Dynamic Covalent Bonds and Hydrogen Bonds to Surmount the Tradeoff between Mechanical Property and Self‐Healing Capacity of Hydrogels

Abstract

The self‐healable hydrogels have attracted increasing attention due to their promising potential for ensuring the durability and reliability of hydrogels. However, they still face a serious challenge to achieve a positive balance between mechanical and healing performance, especially for the room‐temperature autonomous self‐healable hydrogels. Herein, a simple but efficient strategy to fabricate a kind of dynamic boronate and hydrogen bonds dual‐crosslinked double network (DN) hydrogel based on a UV‐initiated one‐pot in situ polymerization of N‐acryloyl glycinamide (NAGA) in polyvinyl alcohol‐borax slime is reported. The obtained PN‐x/PB hydrogels, especially with high content of PNAGA, are shown to possess high mechanical strength, high toughness, and fatigue‐resistance properties as well as excellent self‐healability at room temperature (nearly 88% self‐healing efficiency based on the strain compression test), due to the dynamic DN structure, and the combination of the adaptable and reconfigurable dynamic boronate bonds and hydrogen bonds. Considering the easily available materials and simple preparation process, this novel strategy should offer not only a kind of dynamic DN hydrogel with robust mechanical performance and high self‐healing capability, but also enrich the methodological toolbox for synergistic integration of dynamic covalent bonds and hydrogen bonds to surmount the tradeoff between mechanical properties and self‐healing capacity of hydrogels.

Skin-Adaptable, Long-Lasting Moisture, and Temperature-Tolerant Hydrogel Dressings for Accelerating Burn Wound Healing without Secondary Damage

“…Zwitterionic betaine sulfonate (SBMA), found in plants, animals, and even in the human body, and which holds the merits including excellent biocompatibility, antifouling, moisturizing, and low immunogenicity, has been widely applied for wound dressings, ,, artificial skin, − and cell cryopreservation. , Additionally, NAGA is an ideal alternative material for hydrogel fabrication because its dual amide hydrogen bonds can afford flexibility, superior mechanical properties, and self-healing ability. , And CBMAX is introduced as a chemical cross-linking agent to further improve the strength of hydrogels. Therefore, we fabricated a novel multifunctional hydrogel through one-pot copolymerization of SBMA, NAGA, and CBMAX in a GLY/H 2 O binary solvent system, termed PSNCm hydrogel, where m refers to the mass concentration of CBMAX (mg/mL).…”

“…39,40 Additionally, NAGA is an ideal alternative material for hydrogel fabrication because its dual amide hydrogen bonds can afford flexibility, superior mechanical properties, and self-healing ability. 31,41 And CBMAX is introduced as a chemical cross-linking agent to further improve the strength of hydrogels. Therefore, we fabricated a novel multifunctional hydrogel through one-pot copolymerization of SBMA, NAGA, and CBMAX in a GLY/ First, the effect of the composition of the PSNC hydrogels on their mechanical properties was evaluated by tensile strain tests.…”

Recent progress in conductive self‐healing hydrogels for flexible sensors

“…Borate ester bond is a dynamic reversible reaction, which endows the hydrogel with both self‐healing and stimuli‐responsive properties, such as temperature, pH, and so forth. In addition, the presence of borate ester bonds would be beneficial to enhance the mechanical properties of self‐healing hydrogels, 48 hence, synthetic self‐healing hydrogels based on boric ester bonds have been gradually developed in recent years 54,55 . For example, a strain sensitive, conductive and self‐healing hydrogel based on polyvinyl alcohol (PVA), eutectic gallium and indium (EGain), tannic acid (TA) and borax was recently reported (Figure 5A).…”

“…The flexible supercapacitor developed by this hydrogel has excellent electrical performance, high cycling stability of charge/discharge up to 10,000 times, and good mechanical stability. Zhang's group 55 developed a dual‐crosslinked double‐network (DN) hydrogel based on dynamic boronate and hydrogen bonds via a UV‐initiated in situ polymerization of N ‐acryloyl glycinamide (NAGA) in polyvinyl alcohol‐borax slime (Figure 9B). Due to the synergistic effects of dynamic covalent bond and hydrogen bond, hydrogels owned high mechanical strength, high toughness and fatigue resistance, and good self‐healing properties at room temperature.…”

“…(B) Schematic illustrations of the design and preparation of PNAGA/PVA‐borax (PN‐x/PB) DN hydrogels with multiple‐bond self‐healing mechanism. Reproduced from Reference 55, with permission from 2020 Wiley. (C, D) schematic preparation of self‐healing hydrogel with composite bonds.…”