Intelligent textiles make life wirelessly energetic by coupling radiation energy and human

By innovatively coupling human body and functional fibers, recent inspiring research achieves radiation energy capture, signal transmission and digital visualization while retains flexibilities, softness and durability of textiles and their large-scale fabrications. The single coupled human-fiber system provides absolutely new mechanism and fibrous method to design and produce intelligent textiles and promises to offer more potential applications in home and daily lives. Smart wearable textiles integrating micro/nano electronics into fibers/garments represent state-of-the-art wearable technology and show great potential applications in healthcare, smart city, intelligent robotics, etc.1 To this end, wearable nanosensors, logic circuits, electronic skin, flexible batteries, etc., are incorporated into fabrics to create stretchable and wearable e-textiles.2 The fundamental components, such as sensing elements, chip systems, energy supplies, and interactions between the wearer and the textiles, represent a huge and interdisciplinary research area. Currently, interactive smart textiles which include technologies such as fiber electronics,3, 4 fiber batteries,5, 6 sensors,7 wearables,8 etc., consistently rely on rigid integrated circuit chips (Figure 1a,b). This dependence is due to the inevitable use of von Neumann architecture–based modular electronic systems. However, the intrinsic rigidity of chips significantly restricts the softness and flexibility of fabrics, which hinders seamless integration and reduces energy efficiency. Although fibers can naturally act as electronic building blocks, achieving energy interaction and signal modulation appears impossible without the use of current rigid-structured and millimeter-scale chips. This limitation also impedes the development of textile wearables, industrial fabrication, and future smart applications. Therefore, it is necessary to explore new strategies for developing highly wearable and intelligent textiles that do not rely on external energy devices or rigid chip. Writing in Science, Yang et al. now report a "chipless body-coupled interactive textiles" that capture ambient electromagnetic (EM) energy and transmit wireless signals for human-environment interactions (Figure 1c,d).9 Intelligent textiles achievement ranging from (a) high-performance long fiber batteries,5 Copyright 2021, Springer Nature. (b) Large-area display textiles.8 Copyright 2021, Springer Nature. (c) Comparison between (left) current wireless interactive textile system based on integrated circuit chips and (right) the chipless, wireless interactive textile system and (d) the principle of body-coupled chipless interactive fiber.9 Copyright 2024, American Association for the Advancement of Science. The key advance of this work lies in employing the functional fiber itself to couple with the human body for radiation energy capture, signal transformation and transmission, large-scale production, and final digital-visualization applications. Specifically, Yang et al. have innovatively designed an ultra-intelligent interactive fiber (i-fiber) that acts simultaneously as both a wireless receiver and transmitter, enabling the continuous manufacture of wearable garments. This design addresses the structural concerns of nonconformal attachment, integration, and endurance in conventional electronic textiles. The smart i-fiber features a three-network cross-linked structure and can be fabricated with three functional layers: an induction layer composed of silver-plated nylon fibers, an energy storage layer consisting of BaTiO3 mixed resin, and an optical layer made by doping Cu2+ into ZnS resin. The coupled body-fiber system can capture ubiquitous daily EM radiation energy ranging from ∼3 Hz to ∼13.56 MHz, thereby forming a body-coupled electric field and capacitance between the human body and the conductive core of the i-fiber. Fibrous optical and sensing electrical signals are activated by instantaneous contact with human skin, triggered by the generation of capacitance in the fiber-human contact interface and air breakdown due to electric field intensity, respectively. The body-coupled i-fiber electronic system exhibits extensive improvements in transmission distance and directionality, with minimal influence from specific parameters. The power spectrum, ranging from 0 to 15 MHz, exhibits better efficacy compared to air coupling configurations, which is already confirmed by COMSOL simulations. However, with the distance between fiber and radiation sources increasing, both the electrical and optical energy decrease because of the corresponding decreased intensity of electric field. Furthermore, noncentrosymmetric structural ambient media with high permittivity, such as water (7.08 × 10−10 F·m−1), shows superior EM energy reception capabilities compared to gaseous or liquid mediums, owing to enhanced capacitive power transfer. Notably, manipulating the frequency and amplitude of EM radiation can influence electrical and optical transmission. For example, adjusting the electrical signal can be achieved by increasing the thickness of the core conductive fiber from 18 to 135 μm, which may enhance the electrical signal frequency and weaken its amplitude. Excitation signals with varying frequencies impact the optical emission characteristics. Besides, the wireless electrical and optical signals have the ability to omnidirectionally and uniformly cover distances of 30 and 10 m, respectively, while maintaining a power intensity of 10 nW·cm−2. Impressively, Yang et al. achieved continuous batch weaving while retaining the intrinsic textile properties such as wearability, softness, washability, etc. In the fiber fabrication step, the triple-layer structure made from the layer-by-layer coating technique endows the fiber with great flexibility, characterized by softness (0.095 cN·cm2), fineness (300 μm), breakage strength (56.4 MPa), and the introduction of fluorescent dyes to enrich the optical hues. This distinctive fibrous structure boosts washing durability by blocking the dyes andphosphors to prevent fading and shedding. In garment fabrication, the i-fibrous woven fabric shows greater bending, shearing, surface smoothness, and breathability-approximately 100 times greater (∼604.8 mms−1, ∼1.99 gcm−2h−1) than existing intelligent woven textiles-exhibiting excellent comparability to daily textiles. Significantly, the i-fibrous electronic textiles offer a variety of potential applications, including assisted optical communication for the deaf, virtual reality and augmented reality devices, smart home, etc. By integrating intrinsic textile sensors and effectors into the fibers, the latency-free textile touch-display system allows optical message to be expressed continuously and in real-time, showing a distinctive chipless textile language. Moreover, the system can convey and transform both encoded and decoded signals from the fibrous interface to the user interface. This process is capable of independent logic control and experience no system delays. The textile visualization, coupling EM energy with sensing and wireless transmission, has the potential to interact with electronics, exhibiting innovative textile electronics in smart home application. The inspiring work of Yang et al. introduces a highly innovative mechanism and method for multidisciplinary research across materials science, energy, structural engineering, and electronics in the field of wearable intelligent textiles. The smart applications for human-environment interaction are highly impressive and hold potential application in future deep learning, textile robotics, and brain-computer interfaces. The i-fiber system may need further enhancement in fibrous materials or structures,10 as well as more efficient capture and storage of EM radiation energy, transmission electrical and optical signals with broader bandwidth, and the development of weaving, knitting, non-woven textile structures for different potential applications. To manipulate smart textiles, the potential challenges involve not only incorporating intelligent functions but also maintaining essential qualities such as textile permeability, wearable durability, and washing durability. Despite these inevitable challenges, intelligent textiles promise to become an integral part of our future clothing, home, and lives. Dan Zhou and Zhenfang Zhang contributed equally to this work. This work was supported by the National Natural Science Foundation of China (52203226, 52303054). The authors declare no conflicts of interest.