A robust and fluorescent nanocomposite hydrogel with an interpenetrating polymer network based on graphene quantum dots

Herein, a robust and fluorescent nanocomposite hydrogel polyvinyl alcohol/ poly(N-methylol acrylamide)/graphene quantum dots (PVA/PNMA/GQDs) with interpenetrating polymer network was made-up by in-situ radical polymerization and freeze-thaw method simultaneously. Because of GQDs trapped within the gel matrix as a result of the potent hydrogen bonds generated among PVA, PNMA, and GQDs, the nanocomposite hydrogel with an interpenetrating polymer network displayed strong fluorescence and enhanced mechanical properties. The obtained nanocomposite hydrogel could emit stable bright blue fluorescence at 365 nm radiation. Moreover, the obtained nanocomposite hydrogels were selective to [Fe.sup.3+] ions and demonstrated a rapid and consistent response to [Fe.sup.3+] ions ranging from 20 to 120 [micro]mol/L. Meanwhile, the PVA/PNMA/GQDs hydrogel showed excellent mechanical properties. The compressive strength and strain of the nanocomposite hydrogel were 20.39 MPa and 94.53%, respectively. The tensile fracture strength was 303.06 kPa and the corresponding fracture strain was 198%. Additionally, the gel also possessed extreme fatigue resistance and could tolerate repeated compression without cracking. Therefore, these robust and fluorescent nanocomposite hydrogels have potential applications in flexible sensors for certain metal ions detection and information storage. KEYWORDS fluorescence, graphene quantum dots, interpenetrating polymer networks, mechanical property, nanocomposite hydrogel
1 | INTRODUCTION Graphene quantum dots (GQDs) are widely employed in chemical sensing, biological fluorescent probes, lightemitting devices, photocatalysis, and nonlinear optical devices because of their distinctive optical property, strong [...]