A Dual Cross-Linked Strategy to Construct Moldable Hydrogels with High Stretchability, Good Self-Recovery, and Self-Healing Capability

Most conventional synthetic hydrogels suffer from poor mechanical properties; despite recent significant progress in fabricating tough hydrogels, it is still a challenge to simultaneously realize high stretchability, self-recovery, and self-healing capability in a hydrogel. In this work, a new type of starch/PVA/borax hybrid dual cross-linked (DC) hydrogel was synthesized by a one-pot method. The as-prepared DC hydrogels exhibited mechanical properties of remarkable extensibility (ca. 2485%), excellent toughness (ca. 290.5 kJ m^-3), high compression strength (ca. 547.8 kPa), rapid recoverability (81.9% energy recovery after 30 min), and free-shapeable behavior. More impressively, the DC gels sustained approximately 300 times their own weight and exhibited an outstanding self-healing capability at room temperature both in air and underwater. Furthermore, the adsorption amount of methylene blue onto the anionic DC gel (144.68 mg/g) was much higher than that of corn starch gel. Consequently, the eco-friendly, stable, and biodegradable hydrogels will have a great potential application in removing anionic dyes from the wastewater produced by agriculture and industry.