Ionic liquid-assisted stabilization of MXene in polysaccharide-chitosan hydrogels with mechanical enhancement for catalytic and sensor applications.

In this study, a novel composite functional hydrogel was developed, integrating outstanding mechanical properties, remarkable catalytic activity, and highly sensitive sensing performance. Here, the dispersion behavior of TiCT(MXene) via ionic liquids was examined, focusing on the interplay between surface functional groups of MXene and IL. The study aims to elucidate the mechanisms governing dispersion stability. Subsequently, a novel Polyacrylamide(PAM)/Polyacrylic acid(PAA)/Chitosan/ionic liquid(IL)-MXene hydrogel was designed. PAM/PAA offers a 3D framework, multiple bonds such as hydrogen bonds and electrostatic interactions are formed with PAM/PAA and chitosan by IL-MXene, and the mechanical strength of the hydrogel is further enhanced. Meanwhile, the hydrogel is endowed with good electrical conductivity and sensing capabilities by MXene, which serves as a conductive filler. A strain of 2980 %, a tensile strength of 1050 kPa are displayed by the hydrogel. Simultaneously, it exhibits high gauge factor (GF) and a rapid response time. Under an eco-conscious waste management framework, the functional regeneration of waste hydrogels into high-performance adsorbents represents a significant advancement in sustainable environmental remediation. For instance, the discarded pAAm/PAA/Chitosan/IL-MXene hydrogel system serves as an effective template for the in situ synthesis of gold nanoparticles (Au NPs), demonstrating exceptional catalytic activity in the reduction of 4-nitrophenol (4-NP). Beyond its catalytic efficiency, this composite hydrogel exhibits outstanding mechanical robustness and multifunctionality. In particular, the chitosan within the hydrogel matrix plays a significant role in enhancing antibacterial properties. Moreover, even after undergoing several catalytic cycles, it still maintains >90 % of its original state, indicating excellent cyclic stability and recyclability. Due to these outstanding characteristics, multifunctional hydrogel holds great promise for applications in the fields of flexible sensors and catalysis.