Laser-Patterned Hierarchical Aligned Micro-/Nanowire Network for Highly Sensitive Multidimensional Strain Sensor

SolunumWear: A smart textile system for dynamic respiration monitoring across various postures

We introduce SolunumWear, a multi-sensory e-textile system designed for respiration in daily life settings, addressing the gap in continuous, real-world respiration event monitoring. Leveraging a textile pressure sensor belt to capture chest movements and a wireless data acquisition system, SolunumWear offers a promising solution for both medical and wellness applications. The system's efficacy was evaluated through a human study involving 10 healthy adults (six female and four male) across various breathing rates and postures, demonstrating a strong correlation (R value = 0.836) with the gold-standard system. The study highlights the system's computational and communication efficiencies, with latencies of approximately 4.84 s and 2.13 ms, respectively. These findings highlight the efficacy of SolunumWear as a wireless, wearable technology for respiration monitoring in daily settings. This research contributes to the expanding body of knowledge on smart textile-based health monitoring technologies, demonstrating its potential to provide reliable respiratory data in real-world environments.

Anisotropic V-Groove/Wrinkle Hierarchical Arrays for Multidirectional Strain Sensors with High Sensitivity and Exceptional Selectivity

Flexible strain sensors have been continuously optimized and widely used in various fields such as health monitoring, motion detection, and human-machine interfaces. There is a higher demand for sensors that can sensitively identify both the strain amplitude and direction in real-time to adapt to complex human movements. This study proposes a flexible strain sensor construction strategy based on V-groove/wrinkle hierarchical structures via a facile and scalable prestretching approach. A gold film is sputtered on a V-groove structure soft substrate under a vertical biaxial prestrain. When the strain is released, a variety of wondrous V-groove/wrinkle hierarchical structures are formed. The microstructure and the properties of the resulting sensor can be controlled by adjusting the prestrain, which has obvious anisotropic response characteristics and exhibits high sensitivity (maximum gauge factor up to 20,727.46) and a wide sensing range (up to 51%). In addition, the resulting multidirectional sensor based on double-sided microstructures has an exceptional directional selectivity of 67.39, at an advanced level among all stretchable multidirectional strain sensors reported so far. The sensor can detect human motion signals and distinguish motion patterns, proving its great potential in the field of human motion detection and laying a foundation for high-performance wearable devices.

Age of Flexible Electronics: Emerging Trends in Soft Multifunctional Sensors

With the commercialization of first-generation flexible mobiles and displays in the late 2010s, humanity has stepped into the age of flexible electronics. Inevitably, soft multifunctional sensors, as essential components of next-generation flexible electronics, have attracted tremendous research interest like never before. This review is dedicated to offering an overview of the latest emerging trends in soft multifunctional sensors and their accordant future research and development (R&D) directions for the coming decade. First, key characteristics and the predominant target stimuli for soft multifunctional sensors are highlighted. Second, important selection criteria for soft multifunctional sensors are introduced. Next, emerging materials/structures and trends for soft multifunctional sensors are identified. Specifically, the future R&D directions of these sensors are envisaged based on their emerging trends, namely i) decoupling of multiple stimuli, ii) data processing, iii) skin conformability, and iv) energy sources. Finally, the challenges and potential opportunities for these sensors in future are discussed, offering new insights into prospects in the fast-emerging technology.

Strain-Sensing Composite Nanofiber Filament and Regulation Mechanism of Shoulder Peaks Based on Carbon Nanomaterial Dispersion

Conductive polymer composite-based strain sensors are essential components of flexible wearable devices. However, nonmonotonic responses with shoulder peaks limit their practical application. Herein, we innovatively optimized the shoulder-peak phenomenon in a strain-sensing composite nanofiber filament by regulating carbon nanomaterial dispersion. Further, the preparation methods, characteristics, and performances of the filament strain sensors were systematically introduced. On this basis, transmission electron microscopy, finite element analysis, and mathematic and structural evolution models were used to explore the origin of shoulder peaks and explain the sensing mechanism of conductive networks. Results confirmed that the beacon tower-shaped conductive network designed by constructing nanofiller agglomerates could cause strain concentration and resist the Poisson transverse contraction of nanofibers, considerably improving the monotonicity and sensitivity of the sensor. The strain-sensing performance was optimal when the nanofillers were dispersed using 2.5 wt % of an anionic dispersant. The sensor exhibited a maximum detective strain of 120%, an ultralow detection limit of 0.01%, and high sensitivity and linearity of 9.66 and 0.996 within 20% strain, respectively. Moreover, it showed the advantages of a fast response time (120 ms), excellent durability (3000 cycles), anti-interference, washability, and antibacterial capability. Finally, a smart Kinesio tape was developed for protecting/treating the human body and detecting joint/muscle movement via simple sewing.