Rapid Photothermal Responsive Conductive MXene Nanocomposite Hydrogels for Soft Manipulators and Sensitive Strain Sensors

Abstract

Stimulus-responsive hydrogels are of great significance in soft robotics, wearable electronic devices, and sensors. Near-infrared (NIR) light is considered an ideal stimulus as it can trigger the response behavior remotely and precisely. In this work, a smart flexible stimuli-responsive hydrogel with excellent photothermal property and decent conductivity are prepared by incorporating MXene nanosheets into the physically cross-linked poly(N-isopropyl acrylamide) hydrogel matrix. Because of outstanding photothermal effect and dispersion of MXene, the composite hydrogel exhibits rapid photothermal responsiveness and excellent photothermal stability under the NIR irradiation. Furthermore, the anisotropic bilayer hydrogel actuator shows fast and controllable light-driven bending behavior, which can be used as a light-controlled soft manipulator. Meanwhile, the hydrogel sensor exhibits cycling stability and good durability in detecting various deformation and real-time human activities. Therefore, the present study involving the fabrication of MXene nanocomposite hydrogels for potential applications in remotely controlled actuator and wearable electronic device provides a new method for the development of photothermal responsive conductive hydrogels.

Layer‐by‐Layer Assembly of Multifunctional NR/MXene/CNTs Composite Films with Exceptional Electromagnetic Interference Shielding Performances and Excellent Mechanical Properties

“…As shown in Figure 1c, the stretching vibrations around 3430, 1625, and 1125 cm −1 in FTIR spectrum are assigned to O−H, C=O, C−O, respectively, which are attributed to the large number of surface functional groups formed during the preparation process. [ 38 ] Besides, in Figure 1d, the Ti 3 AlC 2 MAX crystals exhibit intense peaks at 9.6°, 19.2°, 34.0°, 36.8°, 38.8°, 41.2°, and 48.5°, the peak of (002) shifts to a smaller angle indicating the intercalation of lithium ions, simultaneously the weakening of the characteristic peak of Al at 38.8° reveal the etching of Al layer. [ 39 ] Meanwhile, the digital picture of Ti 3 C 2 MXene aqueous solution with typical Tyndall effect shown in Figure 1e signifies their superb hydrophilicity and dispersity.…”

“…Figure 1b of MXene nanosheets along the drawn line in Figure1awe can see that the average thickness of the prepared MXene nanosheets is about 1.3 nm. As shown in Figure1c, the stretching vibrations around 3430, 1625, and 1125 cm −1 in FTIR spectrum are assigned to O−H, C=O, C−O, respectively, which are attributed to the large number of surface functional groups formed during the preparation process [38]. Besides, in Figure1d, the Ti 3 AlC 2 MAX crystals exhibit intense peaks at 9.6°, 19.2°, 34.0°, 36.8°, 38.8°, 41.2°, and 48.5°, the peak of (002) shifts to a smaller angle indicating the intercalation of lithium ions, simultaneously the weakening of the characteristic peak of Al at 38.8°r eveal the etching of Al layer [39].…”

Thermal Properties of MXenes and Relevant Applications

“…Triggers/Drivers Ion transport p [170][171][172]206] Actuators p p p p [173][174]207] Motion of liquid droplets p [208] Self-healing polymerization p [209] Responsive hydrogels p [210] Thermoacoustic devices p [91] All optical modulation devices p p [128,211] Modulators for neuronal electrical activity p [212] Heat management Heaters p p [213] Heat dissipation p p [176][177] Heat insulation p p [178][179] Structure patterning at high temperatures p p [214] Multispectral camouflage devices p p [86,215] reactivity at elevated temperatures up to 2000 °C as well as the temperature-dependent properties) and thermophysical properties (i.e., heat conduction capability, coefficient of thermal expansion, thermoelectric properties, Joule heating and photothermal conversion effect). Though MXenes have shown great potential to be applied in a range of fields based on the unique thermal properties (including biological agents, environmental protection, energy conversion/storage devices, sensors/detectors, triggers for chemical reactions or physical changes, and heat management strategies), this research area is still in its infancy.…”

Bio-Inspired Instant Underwater Adhesive Hydrogel Sensors

“…Various strain and pressure-based wearable sensors have been fabricated to fulfill the requirements of diverse application scenarios. , Notably, hydrogel-based flexible electronics have been widely studied, because of their versatility, mechanical compliance, and good biocompatibility . Many conductive hydrogels with functionalities such as high mechanical strength, adhesion, antifreezing, ambient stability, and self-healing have been developed to meet the needs of various wearable sensor applications. Adhesion ensures a mechanical match between the skin and the sensor, which is one of the prerequisites for wearable sensors to have a sensitive and stable signal output.…”