Fabric computing: Concepts, opportunities, and challenges

Semiconductor fibers for textile integrated electronic systems

The near-room temperature resistance transition in the Lu-H-N compound is repeatedly reproduced, which is clarified to originate from a metal-to-semiconductor/insulator transition rather than superconductivity.

Design and fabrication of wearable electronic textiles using twisted fiber-based threads

Mono-dimensional fiber-based electronics can effectively address the growing demand for improved wearable electronic devices because of their exceptional flexibility and stretchability. For practical applications, functional fiber electronic devices need to be integrated into more powerful and versatile systems to execute complex tasks that cannot be completed by single-fiber devices. Existing techniques, such as printing and sintering, reduce the flexibility and cause low connection strength of fiber-based electronic devices because of the high curvature of the fiber. Here, we outline a twisting fabrication process for fiber electrodes, which can be woven into functional threads and integrated within textiles. The design of the twisted thread structure for fiber devices ensures stable interfacing and good flexibility, while the textile structure features easily accessible, interlaced points for efficient circuit connections. Electronic textiles can be customized to act as displays, health monitors and power sources. We detail three main fabrication sections, including the fabrication of the fiber electrodes, their twisting into electronic threads and their assembly into functional textile-based devices. The procedures require ~10 d and are easily reproducible by researchers with expertise in fabricating energy and electronic devices.

Single body-coupled fiber enables chipless textile electronics

Intelligent textiles provide an ideal platform for merging technology into daily routines. However, current textile electronic systems often rely on rigid silicon components, which limits seamless integration, energy efficiency, and comfort. Chipless electronic systems still face digital logic challenges owing to the lack of dynamic energy-switching carriers. We propose a chipless body-coupled energy interaction mechanism for ambient electromagnetic energy harvesting and wireless signal transmission through a single fiber. The fiber itself enables wireless visual-digital interactions without the need for extra chips or batteries on textiles. Because all of the electronic assemblies are merged in a miniature fiber, this facilitates scalable fabrication and compatibility with modern weaving techniques, thereby enabling versatile and intelligent clothing. We propose a strategy that may address the problems of silicon-based textile systems.

Highly Sensitive Fiber Crossbar Sensors Enabled by Second-Order Synergistic Effect of Air Capacitance and Equipotential Body

Fiber crossbars, an emerging electronic device, have become the most promising basic unit for advanced smart textiles. The demand for highly sensitive fiber crossbar sensors (FCSs) in wearable electronics is increased. However, the unique structure of FCSs presents challenges in replicating existing sensitivity enhancement strategies. Aiming at the sensitivity of fiber crossbar sensors, a second-order synergistic strategy is proposed that combines air capacitance and equipotential bodies, resulting in a remarkable sensitivity enhancement of over 20 times for FCSs. This strategy offers a promising avenue for the design and fabrication of FCSs that do not depend on intricate microstructures. Furthermore, the integrative structure of core-sheath fibers ensures a robust interface, leading to a low hysteresis of only 2.33% and exceptional stability. The outstanding capacitive response performance of FCSs allows them to effectively capture weak signals such as pulses and sounds. This capability opens up possibilities for the application of FCSs in personalized health management, as demonstrated by wireless monitoring systems based on pulse signals.

Wearable and interactive multicolored photochromic fiber display

Endowing flexible and adaptable fiber devices with light-emitting capabilities has the potential to revolutionize the current design philosophy of intelligent, wearable interactive devices. However, significant challenges remain in developing fiber devices when it comes to achieving uniform and customizable light effects while utilizing lightweight hardware. Here, we introduce a mass-produced, wearable, and interactive photochromic fiber that provides uniform multicolored light control. We designed independent waveguides inside the fiber to maintain total internal reflection of light as it traverses the fiber. The impact of excessive light leakage on the overall illuminance can be reduced by utilizing the saturable absorption effect of fluorescent materials to ensure light emission uniformity along the transmission direction. In addition, we coupled various fluorescent composite materials inside the fiber to achieve artificially controllable spectral radiation of multiple color systems in a single fiber. We prepared fibers on mass-produced kilometer-long using the thermal drawing method. The fibers can be directly integrated into daily wearable devices or clothing in various patterns and combined with other signal input components to control and display patterns as needed. This work provides a new perspective and inspiration to the existing field of fiber display interaction, paving the way for future human-machine integration.

Free-standing conductive nickel metal-organic framework nanowires as bifunctional electrodes for wearable pressure sensors and Ni-Zn batteries

Free-standing metal-organic frameworks (MOFs) with controllable structure and good stability are emerging as promising materials for applications in flexible pressure sensors and energy-storage devices. However, the inherent low electrical conductivity of MOF-based materials requires complex preparation processes that involve high-temperature carbonization. This work presents a simple method to grow conductive nickel MOF nanowire arrays on carbon cloth (Ni-CAT@CC) and use Ni-CAT@CC as the functional electrodes for flexible piezoresistive sensor. The resulting sensor is able to monitor human activity, including elbow bending, knee bending, and wrist bending. Besides, the soft-packaged aqueous Ni-Zn battery is assembled with Ni-CAT@CC, a piece of glass microfiber filters, and Zn foil acting as cathode, separator, and anode, respectively. The Ni-Zn battery can be used as a power source for finger pressure monitoring. This work demonstrates free-standing MOF-based nanowires as bifunctional fabric electrodes for wearable electronics.

Highly Sensitive Fiber Pressure Sensors over a Wide Pressure Range Enabled by Resistive-Capacitive Hybrid Response

Soft capacitive pressure sensors with high performance are becoming increasingly in demand in the emerging flexible wearable field. While capacitive fiber pressure sensors have achieved high sensitivity, their sensitivity range is limited to low-pressure levels. As fiber sensors typically require preloading and fixation, this narrow range of high sensitivity poses a challenge for practical applications. To overcome this limitation, the study proposes resistive-capacitive hybrid response fiber pressure sensors (HFPSs) with three-layer core-sheath structures. The trigger and sensitivity enhancement mechanisms of the hybrid response are determined through model analysis and experimental verification. By adjustment of the sensitivity enhancement range of the hybrid response, the sensitivity attenuation of HFPSs is alleviated significantly. The obtained results demonstrate that HFPSs have excellent characteristics such as fast response, low hysteresis, wide response frequency, small signal drift, and good durability. The hybrid response enhances the practical sensitivity of HFPSs for various applications. With enhanced sensitivity, HFPSs can effectively monitor pulse signals at preloads ranging from 0 to 22.7 kPa. This wide range of preloads improves the fault tolerance of pulse monitoring and expands the potential application scenarios of fiber pressure sensors.

Engineering PEDOT:PSS/PEG Fibers with a Textured Surface toward Comprehensive Personal Thermal Management

The wild environment is unpredictable where soaring or plummeting temperatures in extreme weather events can pose serious threats to human lives. Incorporating passive evaporative cooling and controllable electric heating into clothing could effectively protect human beings from such harsh environments. In this work, poly(3,4-ethylene dioxy thiophene):poly(styrene sulfonate)/poly(ethylene glycol) (PPP) fibers with the core-shell structure and attractively textured surface have been successfully prepared via a single-nozzle wet-spinning technique. Results show that the fibers possess fascinating specific surface area (184.8 m²·g^-1), electrical conductivity (50 S·cm^-1), and stretchability (>100%) because of the novel preparation method and hierarchical morphological design. Through simple textile manufacturing routes, PPP fibers can be woven into fabrics easily, which exhibit desirable breathability, washability, and mechanical strength for smart textiles while maintaining favorable hygroscopicity. Benefiting from the textured structure with large specific surface area, PPP fabric exhibits attractile evaporative cooling rate. Practical application tests have demonstrated that under direct sunlight, the surface temperature of the PPP fabric is ∼5.2 and ∼10.8 °C lower than commercial cotton and polyester fabrics, respectively. Meanwhile, as conductive fibers, the resultant PPP fabric can heat under low-power electricity, therefore achieving the effect of "warmth in winter and coolness in summer". The facile fabrication process and elevated performance of PPP fibers present significant advantages for applications in intelligent garments and textiles, as well as comprehensive personal thermal management, which opens a new avenue for future design in these fields.

Imperceptible, designable, and scalable braided electronic cord

Flexible sensors, friendly interfaces, and intelligent recognition are important in the research of novel human-computer interaction and the development of smart devices. However, major challenges are still encountered in designing user-centered smart devices with natural, convenient, and efficient interfaces. Inspired by the characteristics of textile-based flexible electronic sensors, in this article, we report a braided electronic cord with a low-cost, and automated fabrication to realize imperceptible, designable, and scalable user interfaces. The braided electronic cord is in a miniaturized form, which is suitable for being integrated with various occasions in life. To achieve high-precision interaction, a multi-feature fusion algorithm is designed to recognize gestures of different positions, different contact areas, and different movements performed on a single braided electronic cord. The recognized action results are fed back to varieties of interactive terminals, which show the diversity of cord forms and applications. Our braided electronic cord with the features of user friendliness, excellent durability and rich interaction mode will greatly promote the development of human-machine integration in the future.