针对柔性电容传感器的电极易暴露于外界环境和穿着舒适性差等问题,提出一种表面绝缘电极与介质层一体成形的针织电容传感器设计方法。进一步对传感器的力学性能、表面绝缘性能和传感性能进行探究,揭示了织物厚度与间隔丝直径对其性能的影响。研究发现,织物厚度越大,间隔丝直径越小的传感器综合性能越好,其中厚度为8.0 mm、间隔丝直径为0.15 mm的传感器表现最佳,其灵敏度为0.033 kPa^-1,并且具有较低的迟滞性和快速响应时间,对不同性质输入信号(不同压缩距离和不同压缩频率)均具有良好的分辨响应能力,且具有2 000次循环内的重复稳定性,在手部动作识别及液体称重场景展现出较好的压力传感能力。该传感器降低了生产成本,且应用过程中信号稳定,在可穿戴、医疗监测及人机交互界面展现出巨大的应用潜力。

<p id="p00010"><strong>Objective</strong> The electrode of the sensor is placed in the external environment, and the surface conductive material is prone to oxidation and spalling to a certain extent during long-term use, thus affecting the performance of the sensor. Moreover, the air permeability of the packaging material is poor, which reduces the comfort of the human body. Knitting technology can knit conductive yarn into fabric structures, playing a role in improving the comprehensive performance of the sensor. This paper proposes a knitted capacitance sensor with integrated surface insulating electrode and dielectric layer.</p><p id="p00015"><strong>Method</strong> The sensor electrode was designed by double-yarn knitting technology, and cotton yarn and silver-plated yarn were selected for knitting. The cotton yarn always covered on the surface of the silver-coated yarn, so that the electrode was placed inside the sensor, avoiding direct contact with the external environment. Nylon monofilament was used to knit dielectric layer, which was combined with fabric electrode to form capacitive sensor. The spacer fabric capacitive sensor was further placed in the middle of the indenter of the Mark-10 tension/compression meter. A conductive yarn was drawn from each of the upper and lower fabric surfaces of the sensor to connect the positive and negative collets of the precision LCR digital bridge TH2830, making it a complete conductive path. During the test, the digital bridge monitors and recorded the capacitance change of the sensor in real time. By analyzing the relationship between capacitance and pressure, the influence of different spacer fabric thickness and spacer wire diameter on the sensor performance was investigated.</p><p id="p00020"><strong>Results</strong> The mechanical properties, insulation properties, sensitivity, hysteresis, response time and repeatability of the sensor were studied and analyzed. With the increase of thickness, the pressure required to achieve the same strain decreases, and the fabric was more easily compressed. The surface insulation performance of the sensor was further characterized. When the electrode pen was placed in the inner layer of the spacer fabric, the digital multimeter would detect the resistance value, indicating that the surface layer was conductive and acted as the electrode layer of the sensor. However, when the electrode pen is placed on the fabric surface layer, the multimeter would not read the resistance value of the fabric surface correctly. During the whole compression process, sensitivity showed different values in different compression strain ranges. The general trend was that as the compressive stress of the fabric increased, the capacitance change rate of the sensor was positively correlated with it. As the thickness of the spacer fabric increased, the sensitivity of the sensor increased gradually. According to the hysteresis error calculation principle, the maximum hysteresis error occurred at the stress of 6.49 kPa, and the value is 2.24%. The response time curve of the sensor showed that the response time was less than 150 ms. From the the trend of capacitance change rate with time during 2 000 cycles, it can be seen that the sensor maintained stable input and output electrical characteristics during the initial compression stage. To further verify its practical application value in the real application scenario, the capacitive sensor designed was used for the monitoring and recognition of hand movements. Based on the curve peak characteristics, the sensor was able to easily distinguish fingertip press and boxing movements.</p><p id="p00025"><strong>Conclusion</strong> It is found that the sensor with larger thickness and smaller diameter of spacer wire has better overall performance, in which the sensor with thickness of 8.0 mm and spacer wire diameter of 0.15 mm has the best performance with sensitivity being 0.033 kPa^-1. Moreover, it has low hysteresis and fast response time, good resolution and response ability to input signals of different properties (different compression distances and different compression frequencies), and repeated stability within 2 000 cycles, showing good pressure sensing ability in hand motion recognition and liquid weighing scenarios. The sensor reduces the production cost, and the signal is stable during the application process, showing great application potential in wearable, medical monitoring and human-computer interaction interface.</p>

The intense competition from manmade textile fibers makes it imperative to explore promising approaches for improvements in processing efficiency of cotton at reduced cost. Application of liquid ammonia to cotton fibers for improvement in physical properties could provide a practical means of achieving this end.

In recent years, wearable electronic skin has garnered significant attention due to its broad range of applications in various fields, including personal health monitoring, human motion perception, human-computer interaction, and flexible display. The flexible multimodal sensor, as the core component of electronic skin, can mimic the multistimulus sensing ability of human skin, which is highly significant for the development of the next generation of electronic devices. This paper provides a summary of the latest advancements in multimodal sensors that possess two or more response capabilities (such as force, temperature, humidity, etc.) simultaneously. It explores the relationship between materials and multiple sensing capabilities, focusing on both active materials that are the same and different. The paper also discusses the preparation methods, device structures, and sensing properties of these sensors. Furthermore, it introduces the applications of multimodal sensors in human motion and health monitoring, as well as intelligent robots. Finally, the current limitations and future challenges of multimodal sensors will be presented.

针对目前织物基柔性压阻传感器制备工艺相对复杂、导电材料与织物结合度有限等问题,提出以聚二甲基硅氧烷(PDMS)-多壁碳纳米管(MWCNTs)/炭黑(CB)为导电复合材料涂覆非织造布制备压敏层,采用微滴喷射技术在织物表面直接成形叉指型金属电极,制备织物基柔性压阻传感器的方法。当CB与MWCNTs质量比为3∶2时,对不同MWCNTs填充量下导电复合材料形态及制备的压敏层微观形貌观察,并研究其对传感器灵敏度的影响,最后对制得传感器的性能及应用进行测试。结果表明:导电材料在PDMS中分散均匀,导电复合材料与织物结合紧密;当MWCNTs质量分数为2.5%时,所制传感器灵敏度最高可达0.353 kPa^-1,检测范围为0~25 kPa,响应/恢复时间为150/200 ms,最低检测限约为49 Pa,具有良好的重复稳定性(约1 600次)。此外,该传感器可识别出手指按压以及手指和腕部弯曲的压力信号,可应用于人体健康、运动等信号监测。

<p id="p00010"><strong>Objective</strong> Smart textiles are a new type of textile material that highly integrates flexible electronic devices with fabrics, which has great application potential in medical health and sports monitoring. The fabrication of flexible piezoresistive sensors, which enable the interaction between the human body and external information, is crucial for achieving smartness in textiles. Addressing the challenges posed by the intricate preparation process of flexible piezoresistive sensors and the integration of conductive materials with fabrics, this study presents a fabric-based approach to overcome these limitations.</p><p id="p00015"><strong>Method</strong> Polydimethylsiloxane-multi-walled carbon nanotubes/carbon black (PDMS-MWCNTs/CB) was used as a conductive composite material for coating non-woven fabric, aiming to fabricate a piezoresistive layer. Microdrop injection technique was utilized to pattern fork-finger metal electrodes directly on the fabric surface, thereby facilitating the construction of flexible piezoresistive sensors based on fabric. Characterization and analysis of the fabric metal electrodes, conductive composites, piezoresistive layers, and sensors were carried out using an RTS-4 four-probe tester, field-emission scanning electron microscope, tensiometer, digital bridge, and a self-assembled cyclic recirculation device.</p><p id="p00020"><strong>Results</strong> Conductive composites with different mass ratios of CB and MWCNTs were prepared, and the piezoresistive properties of the conductive composites with varying ratios of mass were investigated. The results showed that the resistance increment (<i>R</i>₀-<i>R</i>) of conductive composites tended to increase and then decrease with the increase of CB content under the same pressure. When the mass ratio was 3∶2, the conductive composites exhibited superior piezoresistive response characteristics. Conductive composites and pressure-sensitive layers, incorporating MWCNTs with varying filling contents, were fabricated and investigated. The study encompassed morphological examination of the conductive composites and microstructural analysis of the pressure-sensitive layers. The findings revealed that MWCNTs could be uniformly dispersed within PDMS, with a denser conductive network emerging as the filling quality increased. A synergistic conductive network, characterized by a "grape cluster"-like arrangement, was observed to interconnect MWCNTs and CB within the conductive network. The conductive composite material was uniformly deposited on both the surface and within the nonwoven fabric. Flexibility tests demonstrated that the conductive composite material could be securely adhered to the fabric, with no separation of the conductive material from the nonwoven base. Sensitivity quantifies the ability of the sensor to reflect external stimuli accurately. Sensors with varying MWCNT fillings were prepared and tested to assess sensitivity. The results revealed that the resistance change rate escalated with increasing pressure. The sensor exhibited its highest sensitivity of 0.353 kPa^-1 when the MWCNT filling mass fraction reached 2.5%. The comprehensive performance of the sensor was examined, focusing on aspects such as hysteresis, response/recovery time, repeatability stability, and resolution. The sensor, filled with 2.5% MWCNTs, demonstrated a hysteresis rate of approximately 31.2%, attributed to the inherent structure of the nonwoven material. Its response/recovery time was 150/200 ms, with a minimum detection limit of approximately 49 Pa and excellent repeatability stability (about 1 600 times). Furthermore, the responsiveness of the sensor to human motion signals, including pressure signals from finger presses and finger/wrist flexion, was tested. The results indicated that the sensor could detect and provide feedback on finger pressure, finger bending angle, and continuous wrist bending signals, rendering it suitable for applications in human health and motion signal monitoring.</p><p id="p00025"><strong>Conclusion</strong> This research addresses the difficulty in achieving efficient integration between conductive materials and textiles. The textile-based flexible piezoresistive pressure sensors demonstrate superior sensing capabilities, rendering them appropriate for monitoring human motion signals. These sensors exhibit considerable potential for further development in applications related to human health and movement tracking. Enhanced sensing performance can be achieved by optimizing conductive composite preparation techniques and developing flexible sensors. This sensor may be further enhanced by exploring and incorporating additional fabric substrates.</p>

近年来，材料科学、微/纳结构设计和加工技术的发展赋予了纤维和纺织品各种功能，使其在生理监测、医疗诊断、触觉感知和人机交互等领域具有广泛的应用前景。为进一步推动纤维和纺织品在可穿戴设备领域的应用，本文综述了近几年纺织结构力敏传感器的研究和发展现状及应用。首先，分别从纤维、纱线和纺织品层次出发对纺织结构力敏传感器进行分类，简要介绍了不同纺织结构力敏传感器的优缺点。其次，从制备工艺角度重点讨论了纺织结构力敏传感器的制备方法，包括纺丝技术、涂层技术和织物成型技术，并分析了各种制备方法的优劣。其次，对纺织结构力敏传感器在运动和体育训练、健康监测和人机交互等领域的应用进行了系统总结。最后，展望了纺织结构力敏传感器在智能可穿戴领域的未来发展趋势，以期为新一代可穿戴力敏传感器的研究提供新的思路。

<p id="p00005">In recent years, the development of material science, micro/nano structure design and processing technology have endowed fibers and textiles with various functions, which promote the wide range of applications in the fields of physiological monitoring, medical diagnosis, tactile perception and human-computer interaction. In order to further promote the application of fiber and textile in the field of wearable devices, this paper reviews the recent research and development status and application of textile structure force sensors recently. Firstly, the textile structure force sensors are classified from fiber, yarn and textile level, and the advantages and disadvantages of different textile structure force sensors are briefly introduced. Secondly, the preparation methods of textile structural force sensors are discussed from preparation techniques, including spinning techniques, coating techniques and textile forming techniques, and the advantages and disadvantages of various preparation methods are discussed. Then, the applications of textile structure force sensors in sports and physical training, health monitoring and human-machine interaction are systematically elaborated. Finally, the future development trend of textile structure force sensors in the field of smart wearables is prospected in the hope of providing a novel way for the research of the next generation of wearable force sensors.</p> <p id="p00010"><strong>Content</strong></p> <p id="p00015">1 Introduction</p> <p id="p00020">2 Classification of textile structure force sensor</p> <p id="p00025">2.1 Fiber-based force sensor</p> <p id="p00030">2.2 Yarn-based force sensor</p> <p id="p00035">2.3 Textile-based force sensor</p> <p id="p00040">3 Preparation method of textile structure force sensor</p> <p id="p00045">3.1 Spinning techniques</p> <p id="p00050">3.2 Coating techniques</p> <p id="p00055">3.3 Textile forming techniques</p> <p id="p00060">4 Application of textile structure force sensor</p> <p id="p00065">4.1 Sports and physical training</p> <p id="p00070">4.2 Health monitoring</p> <p id="p00075">4.3 Human-machine interaction</p> <p id="p00080">5 Conclusions and outlook</p>

Wearable electronics, such as smart textiles, are of potential use in healthcare monitoring, human-machine interfaces and environmental analysis. However, the scalability and reliability of the technology is restricted due to challenges related to rapid material degradation, potential toxicity, high production costs and heavy computational workload. Here we report an acoustic-based smart textile technology. The approach, which we term SonoTextiles, uses piezoelectric transducers that are mounted at both ends of glass microfibres and act as transmitters and receivers of acoustic waves. The flexible glass microfibres act as acoustic waveguides and are embedded into the textile substrate, providing precise sensing by measuring wave propagation and energy loss along the fibre in response to stimuli such as touch and bending. We also use acoustic frequency selectivity and frequency-domain signal processing algorithms to enhance computational efficiency. Our acoustic textile is breathable, durable and stable under thermal fluctuations, and we show that it can be used in distributed tactile sensing, hand gesture recognition and respiratory rate monitoring.© The Author(s) 2025.

The wearable electronic skin with high sensitivity and self-power has shown increasing prospects for applications such as human health monitoring, robotic skin, and intelligent electronic products. In this work, we introduced and demonstrated a design of highly sensitive, self-powered, and wearable electronic skin based on a pressure-sensitive nanofiber woven fabric sensor fabricated by weaving PVDF electrospun yarns of nanofibers coated with PEDOT. Particularly, the nanofiber woven fabric sensor with multi-leveled hierarchical structure, which significantly induced the change in contact area under ultra-low load, showed combined superiority of high sensitivity (18.376 kPa, at ~100 Pa), wide pressure range (0.002-10 kPa), fast response time (15 ms) and better durability (7500 cycles). More importantly, an open-circuit voltage signal of the PPNWF pressure sensor was obtained through applying periodic pressure of 10 kPa, and the output open-circuit voltage exhibited a distinct switching behavior to the applied pressure, indicating the wearable nanofiber woven fabric sensor could be self-powered under an applied pressure. Furthermore, we demonstrated the potential application of this wearable nanofiber woven fabric sensor in electronic skin for health monitoring, human motion detection, and muscle tremor detection.

针对静电纺纳米纤维纱线制备技术的产率低、纱线力学性能较差以及生产过程有安全风险和环保隐患的技术现状,对静电纺纳米纤维纱线制备技术进行了综述。首先从纳米纤维聚集加捻原理出发,概述了手动加捻法、电场诱导成纱法、高速旋转加捻法、水浴成纱法和气流辅助成纱法的成纱机制、技术特点及研究现状,指出高速旋转加捻法以纱线制备连续稳定可控等优势成为静电纺纳米纤维纱线制备技术的主流;随后从纤维特性及纱线结构出发,探讨工艺、装置与材料对纱线力学性能的影响,研究认为静电纺纳米纤维纱线增强的本质在于提升纤维取向、纤维抱合紧密度与单纤维力学性能。最后介绍了静电纺纳米纤维纱线的产率现状及影响因素,指出熔体或绿色纺丝液体系的无针静电纺技术与成纱技术的结合是静电纺纳米纤维纱线高效制备的有效途径。

<p id="p00010"><strong>Significance</strong> The development of high-performance yarn materials is a focal point of research in textile engineering and materials science. Electrospun nanofibers possess high specific surface area, porosity, unique interfacial properties, and rich physicochemical properties, and the aggregation of these fibers into yarns is an important approach to developing high-performance yarn materials. In addition, the yarns with anisotropic structural properties allow them to be made into 2-D or 3-D products using weaving or knitting technology. The versatile product structure and ease of functionalization make electrospun nanofiber yarns exhibit excellent properties in fields such as tissue engineering, moisture and heat management, energy sensing, and defense industry applications. However, current electrospinning techniques face challenges in low preparation efficiency and weak mechanical properties, which require further breakthroughs.</p> <p id="p00011"><strong>Progress</strong> In this paper, the forming methods of electrospun yarns from the principle of fiber aggregation and twisting are firstly reviewed, and the representative techniques are summarized. These yarn forming methods can be divided into manual twisting, electricity inducement, water bathing, high speed rotation and airflow coordination. At present, the fiber collector rotary twisting is the most commonly used method for electrospun yarn preparation, which has the advantages of good fiber orientation, yarn uniformity and stable yarn formation process. Subsequently, the influence factors affecting the yield of electrospun nanofiber yarns are discussed and summarized. The yarn yield is affected by the fiber yield, molding method, and material properties and other aspects. As the fiber yield increases, the yarn yield also increases significantly. The combination of four-nozzle needleless electrospun technology and yarn forming technology increases the yarn yield by 5 m/min, but it is still much smaller than that of the conventional spinning method. Finally, the effects of process, device and material on the mechanical properties of yarns were investigated from the perspective of yarn microstructure and fiber properties and are summarized. Moderate twist, high fiber orientation and high fiber crystallinity are all conducive to the yarn strength. At present, the polyacrylonitrile (PAN) electrospun yarns treated by hot drafting and bifunctional poly (ethylene glycol) bisazide (PEG-BA) modification are shown to have the most attractive mechanical properties. The yarn strength reached 1 236 MPa with the tenacity of 118 J/cm³, which initially reached the level of spider silk.</p> <p id="p00012"><strong>Conclusion and prospect</strong> The paper systematically reviews the preparation method, influencing factors influencing yield and strength of electrospun yarns. In order to address the issues of inadequate mechanical properties electrospun nanofiber film, electrospun nanofiber yarns have been prepared using various techniques such as manual twisting, electricity inducement, water bathing, high speed rotation and airflow coordination. The current technology for preparing electrospun nanofiber yarn is primarily based on a solution electrospinning system with single/double needles, resulting in low fiber yield and subsequently low yarn yield. Enhancing the yield of yarn can be achieved by combining needle-free electrospinning systems with spinning technologies, for which it is necessary to investigate the motion patterns of needle-free multi-jet electrospinning and orientation deposition twist methods. Simultaneously, developing an environmentally friendly spinning liquid system is crucial to mitigate risks posed by common organic solvents and achieve a sustainable preparation process. Melt electrospinning technology offers advantages such as complete conversion of raw materials into fibers, minimal jet whipping effects, and solvent-free preparation processes. Exploring novel approaches for enhancing the yield of melt electrospinning fiber thinning and controlling jet aggregation into yarn represents a pivotal avenue towards the sustainable production of electrospun nanofiber yarns. The reinforcement of electrostatically spun nanofiber yarns necessitates a harmonious integration of material system, device design, process control, and post-processing techniques to optimize yarn orientation and mechanical properties at the single fiber level. Investigating the spatial dynamics of electrospun fibers and evolving characteristics of the spinning jet during the fabrication process emerges as an indispensable means to enhance both yarn alignment and tensile strength. Furthermore, implementing post-treatments effectively enhances yarn structure and individual fiber strength, thereby significantly improving overall mechanical performance.</p>