Wearable Electronic Textiles Research Articles

Progress in Materials Development for Flexible Perovskite Solar Cells and Future Prospects.

The perovskite solar cells (PSCs) have emerged as an established technology during the last decade, with the record efficiency of such solar cells having increased from 3.8 % to 25.5 %. Recently, flexible perovskite solar cells (fPSCs) have received much attention from the academic and the industrial communities, owing to their potential for various niche applications, including portable electronics, wearable power sources, electronic textiles, and large-scale industrial roofing. fPSCs are lightweight, bendable, and suitable for roll-to-roll industrial production and can be integrated easily over any surface. This Review discusses the recent development of materials for fPSCs based on various flexible substrates, including plastic, metal, and other flexible substrates, as well as fiber-shaped perovskite solar cells, with a focus on the device structure, material selection for each layer, mechanical flexibility and the environmental stability of the fPSC devices. Finally, future applications and the outlook for fPSCs are also discussed.

A Review of the Use of GPEs in Zinc-Based Batteries. A Step Closer to Wearable Electronic Gadgets and Smart Textiles.

With the flourish of flexible and wearable electronics gadgets, the need for flexible power sources has become essential. The growth of this increasingly diverse range of devices boosted the necessity to develop materials for such flexible power sources such as secondary batteries, fuel cells, supercapacitors, sensors, dye-sensitized solar cells, etc. In that context, comprehensives studies on flexible conversion and energy storage devices have been released for other technologies such Li-ion standing out the importance of the research done lately in GPEs (gel polymer electrolytes) for energy conversion and storage. However, flexible zinc batteries have not received the attention they deserve within the flexible batteries field, which are destined to be one of the high rank players in the wearable devices future market. This review presents an extensive overview of the most notable or prominent gel polymeric materials, including biobased polymers, and zinc chemistries as well as its practical or functional implementation in flexible wearable devices. The ultimate aim is to highlight zinc-based batteries as power sources to fill a segment of the world flexible batteries future market.

Functional Applications of Aloe vera on Textiles: A Review

Aloe vera is one of the oldest medicinal plants in human history. It exhibits 200 or more different biologically-active substances and has attracted many researchers into its potential applications. Researchers have also noted that Aloe vera has fewer adverse effects on human health than other alternative herbal medicines. Aloe vera leaves contain acemannan which is the key functional component. Acemannan is a long-chain polymer consisting of randomly acetylated linear d-mannopyranosyl units and has immune modulation, antibacterial, antifungal and antitumor properties. Due to this functional attribute, the Aloe vera plant is known as a “healing plant”. Researchers claim that Aloe vera treatment can speed wound healing, offer UV protection, and has anti-oxidant and anti-microbial properties. Historically, Aloe vera has been used for a variety of medicinal purposes. Aloe vera contains a moisturizing agent for which it is used in cosmetics. Aloe gel is also used in computer memory hardware to reduce electronic waste. Recently Aloe vera are extensively used to prepare the different types textile composite which are involved in the field of wound healing, tissue engineering, medical textile, health care textiles, curative garments, cosmetotextiles, UV protective textiles, wearable electronic textiles and so on. Aloe vera is used in pre-treatment and printing due to its succulent enzymatic and gummy characteristics. Aloe gel also contains a salty substance that allows its use in natural, eco-friendly dyeing. This review considers the many actual and potential applications of Aloe vera based textile composite materials for therapeutic and other purposes.

Hierarchical design of waterproof, highly sensitive, and wearable sensing electronics based on MXene-reinforced durable cotton fabrics

Superhydrophobic wearable textile electronics are of great promising devices due to their broad application in healthcare monitoring and artificial intelligence, etc. MXenes, the emerging two‐dimensional (2D) carbides and carbonitrides, are ideal candidates for fabricating wearable electronic devices. However, in an effort to maintain its highly conductive and long-term stability of cotton fabrics under harsh condition, it is an imperative demand to prepare superhydrophobic MXenes-textile sensor. Herein, a waterproof, highly sensitive, and wearable multi-mode sensor was successfully fabricated by the construction of 2D MXene nanosheets and zero-dimension (0D) silicon nanoparticles (SiNPs) onto a cotton fibers substrate (MX@SiNPs cotton). The as-cultivated MX@SiNPs cotton exhibited an integration of high-performance sensing toward pression, bending, and torsion, superior sensitivity (S1 = 12.23 kPa−1), a stable response under press-relaxing cycles, and broad sensing ranges (pressure: 8.8 Pa – 70 kPa, bending: 0 – 180°, torsion: 0 – 628 rad m−1). By virtue of its hierarchical structure and low surface energy of the SiNPs layer, the MXenes-textile sensor can maintain intrinsic conductivity under wet and corrosive conditions. The waterproof and highly sensitive MXene-reinforced cotton fabrics lay a basis for the broad-range application and large-scale preparation of the sensor and prolong its service life.

Highly stretchable electro-conductive yarn via wrapping carbon nanotube yarn on multifilament polyester yarn

By virtue of the light-weight, high conductivity, and extraordinary strength, carbon nanotube yarns (CNT yarn, CNTY) are attractive candidates for promoting wearable electronic textiles. However, the unstable conductivity of the CNTY due to piezoelectric characterization of the CNTs may severely affect the conductive performance of the CNTY that is woven into smart textiles. Herein, we report a highly stretchable and stable electro-conductive yarn fabricated by wrapping CNTY on the multifilament polyester yarn (MPY). The stretchable CNTY/MPY wrapping yarn exhibited not only significant-high tensile force (∼727.60 cN) but also ultra-high tensile strain (∼142.76%) compared to pristine CNTY (tensile force ∼211 cN, strain ∼20%). Furthermore, the CNTY/MPY wrapping yarn displayed very limited decrement (<0.5%) of resistance changes after cyclic loading and could still work even during ∼60% stretching. Moreover, this CNTY/MPY wrapping yarn presented steady-state temperature (205.5 °C) with a high quick electro-thermal response (with 1 s) when applied with 2 V voltage. In addition, the CNTY/MPY wrapping yarn could retain the electro-thermal stability when sewed into gloves, displaying low temperature-changes (<2%) under various deformations. Our work explored the potential applications of CNTY/MPY wrapping yarn for wearable smart textiles.

β-Phase-Preferential blow-spun fabrics for wearable triboelectric nanogenerators and textile interactive interface

Abstract Wearable textile electronics have been extensively developed with versatile functionality and self-powered autonomy. Here, we demonstrated β-phase-preferential solution-blow-spun fabrics for application to wearable TENGs and a textile interactive interface. The nonwoven fabric fabricated by solution blow spinning (SBS) was successfully applied as the triboelectric layer in TENGs. The uniaxial elongation of the polymer chains along the fiber axis during the SBS process promoted the formation of polar β-phase crystals in the solution-blow-spun nanofibers, which led to a negative shift in the surface potential and enhancement of the TENG performances. The relationship between the surface charge potential and the crystalline phase of the fabricated nonwoven fabric was comprehensively investigated. The constructed fabric TENG delivered excellent output performances such as a high open-circuit voltage of 260 V, short-circuit current of 27 μA, and high output power of 7 mW; these values were satisfactory for its utilization in the harvesting of biomechanical energy and subsequent driving of commercial portable electronic devices. The fabric TENG was further successfully utilized as a wireless fabric interactive interface for controlling domestic appliances and video playback. The proposed β-phase-preferential blow-spun fabric TENGs are highly promising for application to next-generation intelligent textronics and self-powered human–robot interaction interfaces.

The Evolution of Smart Wrist Band by Using Sensors

In recent years, the integration of various electronic components and sensors with textiles aimed at giving additional functions has become more common. In this respect the wrist band can be made functional while retaining the aesthetic appeal and style at lower cost which is in high demand. Smart textiles are fabrics that have been designed and manufactured to include technologies that provide the wearer with increased functionality. Smart textiles can be produced by knitting, weaving and embroidering with conductive threads, conductive metal coating and screen printing that can be used to develop wearable electronic textiles but amongst these, the use of conductive inks onto textiles has gained interest due to the ease of their use and manufacturing scalability. The emergence of wireless technologies and advancement in on-body sensor design can enable change in the conventional healthcare system, replacing it with wearable ones, centered on the individual. Wearable monitoring systems can provide continuous physiological data, as well as better information regarding the general health of individuals. Thus, such vital-sign monitoring systems will reduce healthcare costs by disease prevention and enhance the quality of life. This dissertation is aimed at developing smart band by incorporating vital-sign monitoring systems. Using this assembly, the recent progress in non-invasive monitoring technologies for chronic disease management is reviewed. Devices and techniques for monitoring pulse rate and body temperatures are discussed in particular. For our research conductive ink and conductive fabrics are presented additionally. The main aim of this project is to produce a wearable wrist band which detects vital body parameters like pulse rate and temperature using sensors, conductive ink and conductive fabric. Finally, the recorded temperature and pulse rate readings are sent to mobile app via Wi-Fi

Machine-Washable Conductive Silk Yarns with a Composite Coating of Ag Nanowires and PEDOT:PSS.

Electrically conducting fibers and yarns are critical components of future wearable electronic textile (e-textile) devices such as sensors, antennae, information processors, and energy harvesters. To achieve reliable wearable devices, the development of robust yarns with a high conductivity and excellent washability is urgently needed. In the present study, highly conductive and machine-washable silk yarns were developed utilizing a Ag nanowire and PEDOT:PSS composite coating. Ag nanowires were coated on the silk yarn via a dip-coating process followed by coating with the conjugated polymer:polyelectrolyte complex PEDOT:PSS. The PEDOT:PSS covered the Ag nanowire layers while electrostatically binding to the silk, which significantly improved the robustness of the yarn as compared with the Ag nanowire-coated reference yarns. The fabricated conductive silk yarns had an excellent bulk conductivity of up to ∼320 S/cm, which is largely retained even after several cycles of machine washing. To demonstrate that these yarns can be incorporated into e-textiles, the conductive yarns were used to construct an all-textile out-of-plane thermoelectric device and a Joule heating element in a woven heating fabric.

Graphene coated textile based highly flexible and washable sports bra for human health monitoring

In this research work, graphene-based highly, conductive, flexible, washable, and breathable textile electrodes have been developed using the pad-dry-cure method. The results show that the electrical conductivity of the graphene-coated textile electrodes was significantly improved from 3.5 MΩ to 400 ± 5.0 kΩ for 12 padding passes. The deposition of poly(3,4-ethylenedioxythiophene) polystyrene sulphonate (PEDOT:PSS) was acquired on reduced graphene oxide (rGO) coated substrate using layer by layer (LbL) technique. The resultant electrodes showed decreased sheet resistance from 150 to 50 kΩ for PEDOT:PSS with a low impedance of 40–150 Hz over the electric potential of 1.0 mV for the detection of high-quality electrocardiograms (ECG) and pulse rate response in different conditions such as rest, walking and running. Consequently, the effect of post-treatment was also analyzed using 5.0 wt% of ethylene glycol (EG) and dimethyl sulfoxide (DMSO), respectively. The sheet resistance was further decreased from 40 kΩ to 130 ±0.5 Ω, which is appropriate for the detection of highly sensitive pulse rate response. The study demonstrates that the pad-dry-cure method can potentially be used for the development of graphene-coated wearable electronic textiles for biomedical and health monitoring devices.

Flexible, twistable and plied electrode of stainless steel Cables@Nickel–Cobalt oxide with high electrochemical performance for wearable electronic textiles

Effective 1D-shaped current collectors and high capacitance active materials are the key components to meet the demand of high performance of flexible 1D electrode for wearable electronic textiles. In this work, a flexible 1D electrode of stainless steel cables@nickel-cobalt oxide is fabricated for wearable electronic textiles. Surface modified stainless steel cables are developed as 1D-shaped current collector to support binary-metal nickel-cobalt oxides as active materials. Stainless steel cables@nickel-cobalt oxide electrodes with various sizes are prepared by spinning technology, including twisting and plying technologies, owing to the advantages of flexibility, spinnability, and weavability of stainless steel cables. Furthermore, the relationship between the ply numbers of twisted stainless steel cables and the electrochemical performance is discussed; and SSC electrodes with various sizes is measured using different metrics, including non-textile and textile standard yarn numbering systems. The as-obtained electrode shows a high specific capacitance under an operating voltage window of 1.0 V, as length capacitance with 113 × 10−3 mAh cm−1 at 0.3 mA cm−1, areal capacitance with 449 × 10−3 mAh cm−2 at 1.2 mA cm−2, volume capacitance 69 mAh cm−3 at 1.0 A cm−3 and linear density capacitance with 433 × 10−3 mAh N−1 and 0.22 × 10−3 mAh Tex−1 at 0.6 mA. This work provides a textile perspective on the field of evaluating the performance of the 1D-shaped electrode for energy collection, conversion, and storage applications.

Futuristic Clothes: Electronic Textiles and Wearable Technologies.

This review summarizes the recent developments and importance of wearable electronic textiles in the past decade. Wearable electronic textiles are an emerging interdisciplinary research area that requires new design approaches. This challenging interdisciplinary research field brings together specialists in electronics, information technology, microsystems, and textiles to make an innovation in the development of wearable electronic products. Wearable electronic textiles play a key role among various technologies (clothing, communication, information, healthcare monitoring, military, sensors, magnetic shielding, etc.). In this review, applications of wearable electronic textiles are described, including an investigation of their fabrication techniques. This review highlights the basic processes, possible applications, and main materials to build wearable E‐textiles and combines the fundamentals of E‐textiles for the readers who have different backgrounds. Moreover, reliability, reusability, and efficiency of wearable electronic textiles are discussed together with the opportunities and drawbacks of the wearable E‐textiles that are addressed in this review article.

Machine-knitted washable sensor array textile for precise epidermal physiological signal monitoring.

Wearable textile electronics are highly desirable for realizing personalized health management. However, most reported textile electronics can either periodically target a single physiological signal or miss the explicit details of the signals, leading to a partial health assessment. Furthermore, textiles with excellent property and comfort still remain a challenge. Here, we report a triboelectric all-textile sensor array with high pressure sensitivity and comfort. It exhibits the pressure sensitivity (7.84 mV Pa-1), fast response time (20 ms), stability (>100,000 cycles), wide working frequency bandwidth (up to 20 Hz), and machine washability (>40 washes). The fabricated TATSAs were stitched into different parts of clothes to monitor the arterial pulse waves and respiratory signals simultaneously. We further developed a health monitoring system for long-term and noninvasive assessment of cardiovascular disease and sleep apnea syndrome, which exhibits great advancement for quantitative analysis of some chronic diseases.

Mechanical Characterization of Embedded Serpentine Conductors in Wearable Electronics

Abstract Wearable electronics undergo stretching, flexing, bending, and twisting during the process of being put on and while being worn. In addition, wearable textile electronics also need to survive under cyclic washing. During such processes, it is necessary to ensure that the electronics as well as the conductors and various other supporting materials remain reliable. In this work, mechanical characterization of various materials in a commercially available smart shirt is presented. The serpentine conductor used in the smart shirt has been carefully examined to understand the strain distribution at various locations under stretching. Both analytical formulations and numerical simulations have been carried out to determine the strain distribution in the serpentine structure, and the results from the simulations have been compared against experimental data obtained through two-dimensional digital image correlation (2D DIC). Various design configurations of the semicircular serpentine structure have been studied in this work, and a relationship between width and the neutral line radius of the semicircular serpentine structure has been obtained to reduce maximum strains in the serpentine structure under stretching.

Long wavy copper stretchable interconnects fabricated by continuous microcorrugation process for wearable applications

AbstractContinuous microcorrugation processes have been developed to form long vertical wavy structures of copper (Cu) foil electrodes for the development of long stretchable interconnects of wearable devices and electronic textiles. Vertical wavy stretchable interconnects in previous studies suffer from low uniformity and limited size due to their wrinkling process with prestretched rubber substrate. Therefore, we propose a continuous metal foil forming process where a long flat Cu foil is continuously deformed into a wavy shape between two three‐dimensional printed gears. 5‐μm Cu foils were corrugated into a wavy structure with waves having 620‐μm pitch and 270‐μm height by the microcorrugation process. The fabricated wavy Cu interconnects showed a 40% stretchability. After microcorrugation, the interconnects were embedded in silicone rubber to protect them from mechanical scratch and improve their elasticity. The interconnects exhibited a 60% stretchability. Finally, a 25 cm‐long stretchable light emitting diodes (LEDs) ribbon with a stretchability over 20% was demonstrated by connecting the LEDs with our wavy Cu interconnects for electronic textile applications. The results demonstrate the effectiveness of our microcorrugation process in the fabrication of long uniform vertical interconnects.

Multifunctional conductive cellulose fabric with flexibility, superamphiphobicity and flame-retardancy for all-weather wearable smart electronic textiles and high-temperature warning device

Flexible wearable electronic textiles are in great demand with the rapid development of intelligent electronic clothing systems. Nonetheless, developing the wearable textiles-based all-weather conductive fabrics with high conductivity and sensitive temperature response property remains a huge challenge. Herein, an all-weather high conductive fabric (ACF) and fire warning sensor (AFWS) have been successfully fabricated on the basis of the multifunctional superamphiphobic cellulose fabric with high conductivity and excellent flame-retardant property. It is worth noting that the as-prepared ACF and AFWS have different surface resistances, which are 1.1 Ω/sq and 1 kΩ/sq, respectively. In comparison with the previously reported conductive textiles, the resulted ACF shows superior electrical stability even under extreme conditions such as complex water phase, oil phase, flame and bending. Moreover, the LED array has been designed and exhibits good electrical properties by virtue of the high conductivity and favorable oil-water repellency of the ACF, demonstrating wide application prospects in large-scale preparation of wearable electronic textiles. In addition, the as-prepared AFWS exhibits sensible temperature-responsive electrical resistance change, which can quickly respond within 3 s. More importantly, the mechanism of rapid reconstruction of the conductive network on the functionalized fabric surface driven by phosphorus blowing agent at high temperature have been well proposed. The current work provides a new idea to develop advanced multifunctional all-weather wearable electronic device, which can effectively realize real-time monitoring of human health and early warning of abnormal high temperature in various harsh outdoor environments.

Wearable Electronic Textiles from Nanostructured Piezoelectric Fibers

AbstractWearable energy harvesting is of practical interest for many years and for diverse applications, including development of self‐powered wireless sensors within garments for human health monitoring. Herein, a novel approach is reported to create wearable energy generators and sensors using nanostructured hybrid piezoelectric fibers and exploiting the enormous variety of textile architectures. It is found that high performance hybrid piezofiber is obtained using a barium titanate (BT) nanoparticle and poly(vinylidene fluoride) (PVDF) with a mass ratio of 1:10. These fibers are knitted to form a wearable energy generator that produced a maximum voltage output of 4 V and a power density 87 μW cm−3 which is 45 times higher than earlier reported for piezoelectric textiles. The wearable energy generator charged a 10 μF capacitor in 20 s which is four and six times faster than previously reported for PVDF/BT and PVDF energy generators, respectively. It also emerges that the established knitted energy harvester exhibits sensitivity of 6.3 times higher in compare with the piezofibers energy generator. A knee sleeve prototype based on a PVDF/BT wearable device for monitoring real‐time precise healthcare is demonstrated. The developed processing method is scalable for the fabrication of industrial quantities of smart textiles.

All-Polymer Conducting Fibers and 3D Prints via Melt Processing and Templated Polymerization.

Because of their attractive mechanical properties, conducting polymers are widely perceived as materials of choice for wearable electronics and electronic textiles. However, most state-of-the-art conducting polymers contain harmful dopants and are only processable from solution but not in bulk, restricting the design possibilities for applications that require conducting micro-to-millimeter scale structures, such as textile fibers or thermoelectric modules. In this work, we present a strategy based on melt processing that enables the fabrication of nonhazardous, all-polymer conducting bulk structures composed of poly(3,4-ethylenedioxythiophene) (PEDOT) polymerized within a Nafion template. Importantly, we employ classical polymer processing techniques including melt extrusion followed by fiber spinning or fused filament 3D printing, which cannot be implemented with the majority of doped polymers. To demonstrate the versatility of our approach, we fabricated melt-spun PEDOT:Nafion fibers, which are highly flexible, retain their conductivity of about 3 S cm–1 upon stretching to 100% elongation, and can be used to construct organic electrochemical transistors (OECTs). Furthermore, we demonstrate the precise 3D printing of complex conducting structures from OECTs to centimeter-sized PEDOT:Nafion figurines and millimeter-thick 100-leg thermoelectric modules on textile substrates. Thus, our strategy opens up new possibilities for the design of conducting, all-polymer bulk structures and the development of wearable electronics and electronic textiles.

Application of highly stretchy PDMS-based sensing fibers for sensitive weavable strain sensors

Compared with the traditional 2D/3D structure sensors, the 1D structure sensors are three-dimensionally deformable and can be woven into flexible textiles for wearable electronics. In the present work, highly stretchy strain sensors were developed using polydimethylsiloxane as the fiber core and multi-walled carbon nanotubes as the sheath. The strain sensors were fabricated with a facile fabrication process and exhibited broad sensing ranges (1–100%), excellent sensitivity, stable resistance, and good mechanical property. It has been demonstrated that the sensors can work under different stress states, such as stretching, twisting, or bending. The sensors based on polydimethylsiloxane and multi-walled carbon nanotubes exhibited a fast electric resistance response. After one circle of stretching/releasing, the sensor takes ~ 1 s to recover back to 70% of the original resistance and 90% within 5 s. The low-cost and straightforward fabrication process makes it a promising route to future flexible textile and wearable sensors.

The effects of deposition time and current density on the electrochemical performance of flexible and high-performance MnO2@PFG composite electrodes.

A novel composite electrode has been fabricated by the direct deposition of MnO2 onto graphene networks surrounding a paper fiber (PFG). The paper fiber between graphene sheets could be used as a flexible substrate for MnO2 nanoparticles, and the microscopic morphologies and electrochemical performances of the MnO2@PFG electrodes were tuned via regulating the deposition current densities and deposition times. 3D graphene on PFG served as a highly conductive backbone with a high surface area for the deposition of the MnO2 nanoparticles, which provided high accessibility to electrolyte ions for shortening the diffusion paths. The MnO2-10-600 s@PFG composite electrode achieved a maximum specific capacitance of 878.6 mF cm−2 with an MnO2 loading mass of 3.62 mg cm−2 (specific capacitance of 187.7 F g−1) at a current density of 0.5 mA cm−2 in a 1 M NaSO4 aqueous solution. Additionally, the MnO2-10-600 s@PFG composite material with the most favorable composite ratio exhibited the highest energy density of 61.01 mW h cm−2, maximum power density of 1249.78 mW cm−2, excellent capacitance retention with no more than 7% capacitance loss after 10 000 cycles and good mechanical flexibility (about 91.06% of its original capacitance after 500 bending times). By combining the electric double layer capacitance of graphene networks with the pseudocapacitance of the MnO2 nanostructures, the flexible electrode showed much enhanced electrochemical capacitance behaviors with robust tolerance to mechanical deformation; thus, it is promising for being woven into textiles for wearable electronics.

Preparation of polypyrrole coated on Polyester Cleanroom Wiper as heater device

Recently, many efforts have been dedicated to achieve lightweight, stretchable, and flexible heat device. Here, the Polyester Cleanroom Wiper coated with poly(pyrrole) as flexible material showing electrothermal properties are reported. Poly(pyrrole) particles are synthesized on the cloth via a simple in situ polymerization method with different Py/FeCl3 concentration ratios. A highly conductive cloth with surface resistance of 23 Ω/sq can be produced by changing the Py/FeCl3 concentration. The flexible composites showed sensitive electrothermal performance, and a steady-state temperature of 89.1°C could be reached at 6 V. In addition, temperature, voltage, and time-dependent temperature results showed that the heating performance was strongly dependent on the resistance and external voltage. Herein, as-prepared composites were further analyzed as ultra-fast responding electrothermal heaters, indicating their great potential in application value as wearable electronic textiles.