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The development of wearable healthcare electronics has created higher demands on both the sensitivity and stretchability of flexible sensors. As it is generally difficult to obtain a trade-off between sensitivity and stretchability, the fabrication of strain sensors with both a wide operating range (≥100%) and high sensitivity (GF ≥ 100) remains a great challenge. Here, we propose for the first time a strategy based on the consolidation of two basic but seemingly paradoxical sensing mechanisms, i.e., slippage and crack propagation mechanisms, to greatly enhance the sensitivity of stretchable strain sensors. Based on stretchable polyurethane (PU) fibers, which can be easily woven into conventional fabrics to produce wearable devices, we present a multilayer sensing structured fiber sensor fabricated by layer-by-layer self-assembly of sliver nanowire (AgNW)/waterborne polyurethane (WPU) layers and MXene layers. The sensor simultaneously exhibits an ultrahigh sensitivity (GF = 1.6 × 107) and a wide operating range (up to 100%), as well as great reliability and stability (1000 cycles) and fast response (344 ms) and relaxation (344 ms). Moreover, smart fabrics were fabricated by integrating fiber strain sensors into different clothes and a prototype body posture monitoring, analysis, and correction system was presented for healthcare applications. Our work not only breaks down the technological wall between high sensitivity and high stretchability of strain sensors, but also shows the great potential applications of wearable, comfortable, and non-intrusive electronics for real-time health monitoring. [ABSTRACT FROM AUTHOR]

Efficient utilization of abundant solar energy for steam generation is an attractive, renewable, and environment-friendly technology for seawater desalination and wastewater purification, enabling solutions to address the global long-standing water scarcity issues. However, the low energy efficiency, high cost and complex systems with multiple components of state-of-the-art technologies hindered their practical applications. Herein, we report the first example of three-dimensional (3D) MXene architecture (3DMA)-based solar steam generators via a facile two-step dip coating process without any annealing or high temperature carbonization. The 3DMAs prepared by a cost-effective, scalable, simple fabrication method show effective broadband solar absorption (∼98%) and excellent solar thermal conversion ability based on 2D to 3D morphological transformation of MXenes, making good use of intrinsic theoretical photothermal performance of MXenes. The particularly hydrophilic nature of MXenes and the macroporous structure of melamine foam allow continuous water supply to 3DMAs owing to their strong capillary effect. As a result, the 3DMAs achieve water evaporation rates of 1.41 and 7.49 kg m−2 h−1 under solar illumination of 1 sun and 5 sun with a superb solar steam efficiency of up to 88.7% and 94.2%, respectively. This scalable 3DMA can be used to produce clean water from both seawater and wastewater with rejections close to 100% for organic dyes and metal ions. This work creates a platform to develop novel composite materials for solar-driven seawater desalination and wastewater purification via opening a new window for the utilization of MXenes as photothermal agents in practical applications. [ABSTRACT FROM AUTHOR]