Photothermal conversion behavior has a vital application to disease therapy, water purification, or uncontacted heaters. The fabrication of high-performance photothermal conversion materials especially for near-infrared (NIR) light and microstructures has attracted a great deal of attention. Among numerous substances, MXene as a new type of 2D material with semi-metallic and unique electromagnetic properties presents a broader absorption of light and even a typical plasmonic absorption near the NIR-I area (808 nm), which has made it suitable for photothermal conversion. Here, we propose a facile approach for preparing a Ti3C2T x /ionic liquid ink with a high photothermal conversion efficiency. The as-prepared ink has showed good wettability of various substrates as well as the high sensitivity of 808 nm NIR light irradiation and a wide range of thermal variation. After packing the ink into a gel pen refill, the flexible thermal chips could be easily obtained just by pen writing on the soft surface with the designed size, which also have become an optimal candidate for the thermal alarm system.

The flexible and portable paper-based sensors have a broad potential application in electronic detection and devices. In this work, a flexible thermoresponsive paper sensor was reported by writing on A4 paper with composite pencil leads which contain thermoresponsive pyrene-based ionic liquid [Pyrmim][Br]. The [Pyrmim][Br] was transferred onto the A4 paper surface with graphite by pencil writing for the facile preparation of thermal-sensitive paper chips. The as-prepared paper sensor was very sensitive to the NIR irradiation and warm objects. What is more, the pliable paper chip also had regular responses along with the varication of the folding angles, which could be employed for the angle goniometer of electronic robots.

Conductive microwrinkles present a superior performance in ultrasensitive sensing, smart controlling, as well as energy conservation because of their unique structures. These wrinkles are usually prepared by the deposition of a thin conductive stiff layer on a soft substrate under a certain strain. However, traditional conductive materials may encounter some deficiencies, such as fragility or poor dispersity, in any solvent. To promote the applicability of conductive microwrinkles, here, we adopt a new twodimensional nanomaterial Ti 3 C 2 T x MXene as the conductive stiff layer to construct the microwrinkles. By combining the spraying and inflating techniques, the hierarchical complex and delicate Ti 3 C 2 T x −polyurethane (Ti 3 C 2 T x −PU) microwrinkles have become facilely available. The characteristic wavelength and amplitude of the microwrinkles could be easily adjusted by altering the inflating height of the PU film or the spraying volume of the Ti 3 C 2 T x solution. Because the as-prepared Ti 3 C 2 T x wrinkles could sensitively generate deformation inducing a resistance change under a force, these structures are also assembled to detect the applied force. The Ti 3 C 2 T x force sensors showed quick response to a tiny force and stable reliability over hundreds of cycles, which hold a promising potential to monitor or employ the microforce.

In this study, coarse sand-supported zero valent iron (ZVI) composite was synthesized by adding sodium alginate to immobilize. Composite was detected by scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). SEM results showed that composite had core-shell structure and a wide porous distribution pattern. The synthesized composite was used for degradation of 2,4-dichlorophenol (2,4-DCP) contamination in groundwater. Experimental results demonstrated that degradation mechanism of 2,4-DCP using coarse sand-supported ZVI included adsorption, desorption, and dechlorination. 2,4-DCP adsorption was described as pseudo-second-order kinetic model. It was concluded that dechlorination was the key reaction pathway, ZVI and hydrogen are prime reductants in dechlorination of 2,4-DCP using ZVI.