Synthesis, Characterization, and Antifogging Application of Polymer/Al₂O₃ Nanocomposite Hydrogels with High Strength and Self-Healing Capacity.

Hydrogels with outstanding mechanical performance, self-healing capacity, and special functionality are highly desirable for their practical applications. However, it remains a great challenge to achieve such hydrogels by a facile approach. Here, we report a new type of nanocomposite hydrogels by in situ copolymerization of acrylic acid (AA) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) using alumina nanoparticles (Al2O3 NPs) as the cross-linkers. The obtained hydrogels are highly stretchable and compressible, which could sustain large-scale extension (>1700%) or compression (90%) without failure, and exhibit tensile and compressive strength up to 660 kPa and 8.3 MPa, respectively. Furthermore, this kind of hydrogel also display considerable self-healing capacity due to their noncovalent cross-linking mechanism, as well as the hydrogen-bonding interactions between polymer chains. More interestingly, it was found that the resultant gels possess a long-lasting antifogging property that could prevent the formation of fog on the glass plate above hot water for at least 90 min. It is expected that this novel type of hydrogel would show great promise for various applications, including soft robots, artificial muscles, and optical devices.