Self-healable poly(acrylic acid-co-maleic acid)/glycerol/boron nitride nanosheet composite hydrogels at low temperature with enhanced mechanical properties and water retention

• Published in: Soft matter Vol. 15; no. 18; pp. 3680 - 3688
• Main Authors: Xue, Shishan, Wu, Yuanpeng, Guo, Meiling, Xia, Yuanmeng, Liu, Dan, Zhou, Hongwei, Lei, Weiwei
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 08.05.2019
• Subjects: Acids; Acrylic acid; Boron; Boron nitride; Freezing; Glycerol; Hydrogels; Hydrogen bonding; Hydrogen bonds; Low temperature; Maleic acid; Mechanical properties; Modulus of elasticity; Moisture content; Nanosheets; Retention; Stiffness; Stretchability; Temperature effects; Tensile strength; Tissues; Water content
• ISSN: 1744-683X; 1744-6848
• DOI: 10.1039/c9sm00179d

Many living tissues possess excellent mechanical properties and water retention which enable them to self-heal at room temperature even below the freezing temperature of water. To mimic the unique features of living tissue, a poly(acrylic acid-co-maleic acid) composite hydrogel with enhanced mechanical properties and remarkable water retention was fabricated under accessible conditions. The hydrogel is functionalized by amino group modified boron nitride nanosheets (BNNS-NH2)/glycerol and exhibits self-healing abilities at low temperature. The self-healing process occurs through the re-establishing of hydrogen bonds and metal coordination interactions at the damaged surfaces. Its anti-freezing abilities enable the hydrogel to self-heal at -15 °C, and the self-healing efficiency based on tensile strength reaches up to ∼70%. Moreover, glycerol also endows the hydrogel with long-lasting water retention, which remains a water content of ∼99 wt% for more than 30 days. Meanwhile, the simultaneous introduction of BNNS-NH2 and glycerol significantly improved the mechanical properties of the hydrogel, which displays great stretchability (∼474%), tensile strength (∼151.3 kPa), stiffness (Young's modulus of ∼62.75 kPa) and toughness (∼355.13 kJ m-3). It is anticipated that these novel hydrogels will develop many fields and be exploited for new applications in extensive external environments.