Fast fabrication of stimuli-responsive MXene-based hydrogels for high-performance actuators with simultaneous
Lingke Liu1, Minjuan Gao1, Xingyu Fan1
1Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037 China; College of Chemical Engineering, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing 210037 China.
Abstract:
Poly(N-isopropylacrylamide) (PNIPAM) composite hydrogels have recently emerged as promising candidates for soft hydrogel actuators. However, developing a facile and fast method to obtain multifunctional PNIPAM hydrogel actuators with simulating biological versatility remains a major challenge. Herein, we developed a fast-redox initiation system to prepare PNIPAM/sodium carboxymethyl cellulose (CMC)/T3C2Tx MXene nanocomposite hydrogel with multidirectional actuating behaviors and improved mechanical properties. The rapid thermoresponsive behavior of the PNIPAM/CMC/MXene layer bestows its corresponding bilayer actuator with an extraordinary actuation speed of 9.36°/s in hot water. Owing to the high photothermal conversion of MXenes, this PNIPAM/CMC/MXene hydrogel displays a range of remote-controlled actuations upon NIR light irradiation, including bending, rolling, displacement, and simulations of the sea eel's hunting behaviors in a water environment. More importantly, based on the excellent electrical properties of MXene, the PNIPAM/CMC/MXene-based hydrogel actuators have accomplished a self-sensing function by integrating the surface temperature-bending angle-the relative resistance changes during the NIR light-driven actuation process. The photothermal actuator's integrated actuation and sensing capabilities have facilitated the feedback of the contact and movement dynamics of the bioinspired artificial tongue. The straightforward preparation and multifunctional design of MXene-based hydrogel may facilitate the development of soft smart actuators.
