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Conductive hydrogel is considered a promising wearable sensor material. Developing flexible conductive hydrogel sensors with stretchability, adhesion, and stability remains challenging. In this study, a transparent, self‐adhesive, antifreeze, anti‐UV, stretchable, conductive, and reusable hydrogel with polyacrylamide/glycerol/gelatin/tannic acid/Fe3+ (PGGT‐Fe3+) structure is successfully constructed through a simple one‐pot polymerization method. The PGGT‐Fe3+ hydrogel is composed of dual networks of polyacrylamide and gelatin for organic cross‐linking, using water/glycerol as the dispersion medium, and incorporates a viscous substance: tannic acid, and a conductive substance: metal ions (Fe3+). Due to the introduction of the abundant amino, carboxylic acid, and hydroxyl functional groups on gelatin and tannic acid, the PGGT‐Fe3+ hydrogel exhibits excellent and repeatable adhesion capabilities on various surfaces (including glass, metal, plastic, and pigskin) with maximum adhesion strength of 98 kPa when attached to pigskin. Furthermore, based on the stable conductive network and high conductivity, the hydrogel not only exhibits strain sensitivity, fast response, and stability but also can stably collect epidermal bio signals. In conclusion, this work provides a new approach to the design and development of next‐generation multifunctional conductive hydrogels and opens up vast possibilities for their applications in the flexible electronics field. [ABSTRACT FROM AUTHOR]

Developing multifunctional electronic fabrics with sensing capabilities, electromagnetic interference (EMI) shielding, and Joule heating performance holds great significance for health monitoring and medical protection. However, most fabrics struggle to combine multiple functions and optimize them simultaneously. For example, achieving both high sensitivity and a wide detection range in sensing devices remains a challenge. In this paper, we present a multidimensional composite structure comprising MXene Ti3C2Tx nano lamellar, self-assembled lotus leaf-like MXene/EGaIn and carbon nanotubes (CNTs) assembled on the surface of thermoplastic polyurethane to create a multifunctional MXene EGaIn/MXene CNT fabric (MEMC fabric). The multidimensional materials form a stable conductive network under tension. As a strain sensor, the MEMC fabric exhibits a large sensing range (0–360%) and ultra-high sensitivity (GF ∼ 114,700), making it suitable for artificial eardrum research. Additionally, MEMC demonstrates excellent EMI shielding effect (∼73 dB) and maintains good EMI shielding performance under tensile conditions. The fabric also showcases outstanding Joule heating performance (low voltage drive ∼2 V, fast heating time ∼13 s, and high heating stability ∼4000 s). This paper also demonstrates the multifunctional combination of MEMC fabrics, achieving simultaneous sensing, EMI shielding, and Joule heating functions under stretching. This work offers a forward-looking approach for constructing multifunctional composite fabrics, and the resulting MEMC composite materials hold potential applications in portable electronic devices and defense industries. [ABSTRACT FROM AUTHOR]

Ti3C2Tx MXene has a high specific surface area and high conductivity, and can be used in the field of humidity sensing. By controlling the surface termination and microstructure of the material, it is expected to improve the humidity sensing performance of Ti3C2Tx MXene. In this paper, we report a method of electrolytic intercalation treatment of Ti3C2Tx MXene in NaOH solution. Theoretical and experimental results show that this method can remove the original F terminations from the surface of Ti3C2Tx MXene and form a large number of OH and O terminations. The partial oxidation of the surface and the replacement of terminations and the insertion of Na+ lead to the change of the Ti3C2Tx MXene layer morphology from flat to curly and significantly improve the hydrophilicity and resistance. The curly flake structure constructs a fast channel for the entry and exit of water molecules which improves the hydration/dehydration efficiency of the material; the enhanced hydrophilicity of the material sharply reduces the resistance of the material after moisture absorption, which significantly improves the responsiveness of Ti3C2Tx MXene to humidity. The curly flake Ti3C2Tx MXene humidity sensor has an ultra-high sensitivity of S = 1.2 × 105 (two orders of magnitude higher than that of the reported humidity sensor based on MXene), with a fast response rate (2 s), good repeatability and stability (4 weeks), and it can be used for the analysis of human respiration rate, and also for non-contact sensing detection of the human body and environmental humidity detection. [ABSTRACT FROM AUTHOR]

The increasing pressure and unhealthy lifestyle are gradually eroding the physical and mental health of modern people. As a key hormone responsible for maintaining the normal functioning of human systems, cortisol plays a vital role in regulating physiological activities. Moreover, cortisol can serve as a marker for monitoring psychological stress. The development of cortisol detection sensors carries immense potential, as they not only facilitate timely adjustments and treatments by detecting abnormal physiological indicators but also provide comprehensive data for conducting research on the correlation between cortisol and several potential diseases. Here, we report a molecularly imprinted polymer (MIP) electrochemical biosensor that utilizes a porous composite (MXG) modified electrode. MXG composite is prepared by combining Ti 3 C 2 T x -MXene sheets and graphene (Gr). MXG composite material with high conductive properties and large electroactive surface area promotes the charge transfer capability of the electrode surface, expands the effective surface area of the sensor, and increases the content of cortisol-imprinted cavities on the electrode, thereby improving the sensing ability of the sensor. By optimizing the preparation process, the prepared sensor has an ultralow lower limit of detection of 0.4 fM, a wide detection range of 1 fM-10 μM, and good specificity for steroid hormones and interfering substances with similar cortisol structure. The ability of the sensor to detect cortisol in saliva was also confirmed experimentally. This highly sensitive and selective cortisol sensor is expected to be widely used in the fields of physiological and psychological care.