Smart Textile Systems Research Articles

Ultrahigh Responsivity and Robust Semiconducting Fiber Enabled by Molecular Soldering-Governed Defect Engineering for Smart Textile Optoelectronics.

Semiconducting fibers (SCFs) are of significant interest to design next-generation wearable and comfortable optoelectronics that seamlessly integrate with textiles. However, the practical applications of current SCFs are always limited by poor optoelectronic performance and low mechanical robustness caused by uncontrollable multiscale structural defects. Herein, a versatile in situ molecular soldering-governed defect engineering strategy is proposed to construct ultrahigh responsivity and robust wet-spun MoS2 SCFs, by using a π-conjugated dithiolated molecule to simultaneously patch microscale sulfur vacancies within MoS2 nanosheets, diminish mesoscale interlayer voids/wrinkles, promote macroscale orientation, build long-range photoelectron percolation bridges, and provide n-doping effect. The derived MoS2 SCFs exhibit over two orders of magnitude higher responsivity (144.3 A W-1) than previously reported fiber photodetectors, 37.3-fold faster photoresponse speed (52ms) than pristine counterpart, and remarkable bending robustness (retain 94.2% of the initial photocurrent after 50000 bending-flattening cycles). Such superior robustness and photodetection capacity of MoS2 SCFs further enable large-scale weaving of reliable smart textile optoelectronic systems, such as direction-identifiable wireless light alarming system, modularized mechano-optical communication system, and indoor light-controlled IoT system. This work offers a universal strategy for the scalable production of mechanically robust and high-performance SCFs, opening up exciting possibilities for large-scale integration of wearable optoelectronics.

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 4.84s and 2.13ms, 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.

22‐4: Invited Paper: Fiber‐Like Oxide Thin‐Film Transistors for Large‐Area Smart Textile Systems

This work demonstrates flexible and textile electronic concepts bridged to create innovative and free form factor textile electronic systems. In particular, it focuses on oxide thin‐film transistor development on fiber‐like polymeric substrates to assure compatibility with weaving processes and interconnectivity with other fiber‐based electronic components. By process tuning and device engineering, similar performance to oxide TFTs on glass was achieved, even under a low thermal budget (sub‐200 °C). Integration capability is demonstrated through a rollable 46” smart textile lighting system, able to display variable information provided by an external stimuli detection through fiber‐based devices.

Multifunctional flame-retardant cotton fabric with hydrophobicity and electrical conductivity for wearable smart textile and self-powered fire-alarm system

The domain of smart textiles represents a widely researched area, showcasing promising prospects. Herein, a multifunctional smart textile (CF@PM-AA) has been designed and fabricated, amalgamating flame retardancy, electrical conductivity, and hydrophobicity into a unified entity. The flame retardant, synthesized through the reaction between amino trimethylene phosphonic acid and allantoin, was impregnated into cotton fabric through a facile impregnation method. Through surface modification with polydimethylsiloxane and multi-walled carbon nanotubes, the obtained CF@PM-AA acquires exceptional hydrophobic and acid-base environment durability. Significantly, the electrical conductivity of CF@PM-AA is greatly enhanced, with a reduced resistance down from 15.9 GΩ to 13 MΩ. Based on their electrical characteristics, the copper sheet and CF@PM-AA function as the electrode and friction layers, respectively, in the construction of the triboelectric nanogenerator. This configuration produces a voltage output of up to 125.6 V at a frequency of 4 Hz. Given its outstanding flame retardancy, hydrophobicity, and electrical performance, CF@PM-AA can be integrated into firefighting suits to establish a fire-alarm system with remote signal transmission function, enhancing personnel safety. Simultaneously, the CF@PM-AA holds promise for diverse applications in wearable flame-retardant and fire-alarm systems, opening new avenues for smart textile utilization in the Internet of Things domain.

Three-lead in vivo measurement method for determining the skin-electrode impedance of textile electrodes

The rise of interest in wearable sensing of bioelectrical signals conducted via smart textile systems over the past decades has resulted in many investigations on how to develop and evaluate such systems. All measurements of bioelectrical signals are done by way of electrodes. The most critical parameter for an electrode is the skin-electrode impedance. A common method for measuring skin-electrode impedance is the two-lead method, but it has limitations because it relies on assumptions of symmetries of the body impedance in different parts of the body as well as of the skin-electrode impedances. To address this, in this paper we present an easy-to-use and reliable three-lead in vivo method as a more accurate alternative. We aim to show that the in vivo three-lead method overcomes all such limitations. We aim at raising the awareness regarding the possibility to characterize textile electrodes using a correct, accurate and robust method rather than limited and sometimes inadequate and uninformative methods. The three-lead in vivo method eliminates the effect of body impedance as well as all other contact impedances during measurements. The method is direct and measures only the skin-electrode impedance. This method is suitable for characterization of skin-electrode interface of textile electrodes intended for both bioelectrical signals as well as for electrostimulation of the human body. We foresee that the utilization of the three-lead in vivo method has the potential to impact the further development of wearable sensing by enabling more accurate and reliable measurement of bioelectrical signals.

A review on the recent developments in design and integration of electromyography textile electrodes for biosignal monitoring

Due to recent developments in wearable sensor technology, textile electrodes are routinely being employed in electromyography (EMG) for continuous monitoring of the biosignals from the muscles. However, the performance of such smart textile-based health monitoring devices depends on several factors such as, the sensitivity (impedance), durability (reusable/washable), users' comfort ability, integrability, and automatability. In this article we review the characteristics and the performance of the EMG textile electrodes, in the context of functional textile materials, smart textile materials, and smart textile systems for biosignals monitoring. The functional textile materials are confined to signal transmission alone, whereas, the smart textile materials include signal transducers and sensors. The more advanced smart textile systems include signal conditioning circuits with displays. Nowadays, textile-based sensors embedded in garments are becoming a part of users' normal life, in particular, the textile systems that continuously monitor the vital physiological signals from muscles are being sought after in healthcare settings.

Validation of an Equine Smart Textile System for Heart Rate Variability: A Preliminary Study.

Electrocardiograms (ECGs), and associated heart rate (HR) and heart rate variability (HRV) measurements, are essential in assessing equine cardiovascular health and fitness. Smart textiles have gained popularity, but limited validation work has been conducted. Therefore, the objective of this study was to compare HR and HRV data obtained using a smart textile system (Myant) to the gold-standard telemetric device (Televet). Simultaneous ECGs were obtained using both systems in seven horses at rest and during a submaximal exercise test. Bland-Altman tests were used to assess agreement between the two devices. Strong to perfect correlations without significant differences between the two devices were observed for all metrics assessed. During exercise, mean biases of 0.31 bpm (95% limits of agreement: -1.99 to 2.61) for HR, 1.43 ms (-11.48 to 14.33) for standard deviation of R-R intervals (SDRR), and 0.04 (-2.30 to 2.38) for the HRV triangular index (TI) were observed. A very strong correlation was found between the two devices for HR (r = 0.9993, p < 0.0001) and for HRV parameters (SDRR r = 0.8765, p < 0.0001; TI r = 0.8712, p < 0.0001). This study demonstrates that a smart textile system is reliable for assessment of HR and HRV of horses at rest and during submaximal exercise.

Reconfigurable neuromorphic memristor network for ultralow-power smart textile electronics

Neuromorphic computing memristors are attractive to construct low-power- consumption electronic textiles due to the intrinsic interwoven architecture and promising applications in wearable electronics. Developing reconfigurable fiber-based memristors is an efficient method to realize electronic textiles that capable of neuromorphic computing function. However, the previously reported artificial synapse and neuron need different materials and configurations, making it difficult to realize multiple functions in a single device. Herein, a textile memristor network of Ag/MoS2/HfAlOx/carbon nanotube with reconfigurable characteristics was reported, which can achieve both nonvolatile synaptic plasticity and volatile neuron functions. In addition, a single reconfigurable memristor can realize integrate-and-fire function, exhibiting significant advantages in reducing the complexity of neuron circuits. The firing energy consumption of fiber-based memristive neuron is 1.9 fJ/spike (femtojoule-level), which is at least three orders of magnitude lower than that of the reported biological and artificial neuron (picojoule-level). The ultralow energy consumption makes it possible to create an electronic neural network that reduces the energy consumption compared to human brain. By integrating the reconfigurable synapse, neuron and heating resistor, a smart textile system is successfully constructed for warm fabric application, providing a unique functional reconfiguration pathway toward the next-generation in-memory computing textile system.

Simulations of lead-free organic–inorganic perovskites under tensile/compressive loads and different force fields

Organic–inorganic perovskites provide a favourable material system for photon and force-driven electronic systems. Lead-free methylammonium perovskite has the advantage, being an eco-friendly and simple material that can be used directly in smart and wearable electronic textile systems. However, its usage in wearables risks it being worn off and collapsing in a short time. This research assessed the resistance of lead-free methylammonium perovskite (CH3NH3SnI3) to mechanical impacts by employing Large-scale Atomic/Molecular Massively Parallel Simulator molecular dynamics theories. To show the effect, stress–strain behaviour and Young’s moduli of CH3NH3SnI3 were simulated by considering its molecular lattice. First, a two-axis (planar) model simulates stress and strain. Further computations were then performed to obtain the Poisson ratio, shear modulus, torsional modulus, and Pugh’s ratio. This simulation’s output renders a theoretical framework for the design and engineering of long-lasting wearable photon, and force-driven electronic and wearable devices based on CH3NH3SnI3.

Smart Textile Sock System for Athletes' Self-Correction during Functional Tasks: Formative Usability Evaluation.

(1) Background: The development of a lightweight, easy-to-use system that measures the foot’s plantar pressure is becoming an increasingly important area of research in physiotherapy. For further development of the smart sock system, a formative usability study was conducted, where the smart textile sock sensor system was used for self-correction during functional tasks; (2) Methods: Five athletes from the football school participated in the formative usability study. Athletes performed pre-defined functional tasks for self-correction when interacting with the smart textile sock system. Formative usability evaluation methods: effectiveness (task success rate, error rate), efficiency (time-based), satisfaction evaluated by System Usability Scale (SUS); (3) Results: Formative usability indicators: task completeness effectiveness ranged from 40% to 100% in the first- and second-stage tasks. Completed task efficiency time: Stage 1, from 4.2 s (SD 1.3) to 88.8 s (SD 19.8); Stage 2, from 7.2 s (SD 1.9) to 9.6 s (SD 2.1). Satisfaction was assessed by the SUS system user group with 76 points (SD 7.42), which indicates “good” satisfaction; (4) Conclusions: formative usability indicators showed the need for technical improvements to the smart textile sock pressure sensor system. The SUS results indicate “good” satisfaction with the smart textile sock pressure sensor system and its application.

Smart textile lighting/display system with multifunctional fibre devices for large scale smart home and IoT applications

Smart textiles consist of discrete devices fabricated from—or incorporated onto—fibres. Despite the tremendous progress in smart textiles for lighting/display applications, a large scale approach for a smart display system with integrated multifunctional devices in traditional textile platforms has yet to be demonstrated. Here we report the realisation of a fully operational 46-inch smart textile lighting/display system consisting of RGB fibrous LEDs coupled with multifunctional fibre devices that are capable of wireless power transmission, touch sensing, photodetection, environmental/biosignal monitoring, and energy storage. The smart textile display system exhibits full freedom of form factors, including flexibility, bendability, and rollability as a vivid RGB lighting/grey-level-controlled full colour display apparatus with embedded fibre devices that are configured to provide external stimuli detection. Our systematic design and integration strategies are transformational and provide the foundation for realising highly functional smart lighting/display textiles over large area for revolutionary applications on smart homes and internet of things (IoT).

Modular Piezoresistive Smart Textile for State Estimation of Cloths.

Smart textiles have found numerous applications ranging from health monitoring to smart homes. Their main allure is their flexibility, which allows for seamless integration of sensing in everyday objects like clothing. The application domain also includes robotics; smart textiles have been used to improve human-robot interaction, to solve the problem of state estimation of soft robots, and for state estimation to enable learning of robotic manipulation of textiles. The latter application provides an alternative to computationally expensive vision-based pipelines and we believe it is the key to accelerate robotic learning of textile manipulation. Current smart textiles, however, maintain wired connections to external units, which impedes robotic manipulation, and lack modularity to facilitate state estimation of large cloths. In this work, we propose an open-source, fully wireless, highly flexible, light, and modular version of a piezoresistive smart textile. Its output stability was experimentally quantified and determined to be sufficient for classification tasks. Its functionality as a state sensor for larger cloths was also verified in a classification task where two of the smart textiles were sewn onto a piece of clothing of which three states are defined. The modular smart textile system was able to recognize these states with average per-class F1-scores ranging from 85.7 to 94.6% with a basic linear classifier.

In Situ Formation of Ag Nanoparticles for Fiber Strain Sensors: Toward Textile-Based Wearable Applications

Wearable electronic devices have attracted significant attention as important components in several applications. Among various wearable electronic devices, interest in textile electronic devices is increasing because of their high deformability and portability in daily life. To develop textile electronic devices, fiber-based electronic devices should be fundamentally studied. Here, we report a stretchable and sensitive fiber strain sensor fabricated using only harmless materials during an in situ formation process. Despite using a mild and harmless reducing agent instead of typical strong and hazardous reducing agents, the developed fiber strain sensors feature a low initial electrical resistance of 0.9 Ω/cm, a wide strain sensing range (220%), high sensitivity (∼5.8 × 104), negligible hysteresis, and high stability against repeated stretching-releasing deformation (5000 cycles). By applying the fiber sensors to various textiles, we demonstrate that the smart textile system can monitor various gestures in real-time and help users maintain accurate posture during exercise. These results will provide meaningful insights into the development of next-generation wearable applications.

Smart textiles: A toolkit to fashion the future

Smart textiles are adaptive materials that use established textile methods to integrate multifunctionalities beyond apparels. Despite recent advancement, a significant gap exists between commercial needs and the academic state of the art. In this perspective, we aim to address the gap by (i) holistically investigating smart textile system operation, (ii) exploring production methods and materials for stimuli-responsive smart textiles, (iii) discussing key emerging application areas for stimuli-responsive textiles, and (iv) identifying markets, production techniques, and strategies for future development. Stimuli-responsive smart textiles rely on materials and processes to interact with the environment and wearer. Smart textile applications, such as assistive soft robotics, smart healing, and thermal comfort regulation, require textiles to meet the needs of form and function. Smart textile commercialization requires the identification of markets ready for adaptive textiles, wherein a smart phone or patch does not address the consumer needs. Interdisciplinary collaborations can focus efforts to the right applications, bridging the gap between academic research and product relevance, bringing smart textiles into the future.

Fabrication of interdigitated capacitor on fabric as tactile sensor

Smart textile has opened a new paradigm of application. Therefore, interest in developing a textile-based sensor system to interact with a machine has been elevated significantly. Touch and pressure are vital interests for multipurpose use, leading to the prior work on developing textile-based sensors using embroidery, multi-layer weaving, and different printing processes. The complexity of those works requires an additional setup and machines for the application. This paper presents a novel approach to developing a low-cost and scalable tactile sensor to sense touch and conjugated pressure exerted over the fabric by means of capacitance variation using commercial stainless-steel thread and low-cost lockstitch sewing machine. The research focused on determining the distinct possibility of sensing the touch stimuli and finger pressure as the capacitance range variation and finding out the allusive structural variables of interdigitated capacitor (IDC) and parallel plate capacitor (PPC) of the sensor. For IDC, the mean capacitance variation found 1.28 pF/gm, whereas 0.81pF/gm found for the PPC structure. For both cases, 11.3 gm measured as the least possible sensing pressure. The repetitive percentage (%) of the sensor (IDC) found 97.91 after testing 1016 consecutive finger pressings cycles. The research demonstrated a circuit where the capacitance range was segmented into five slots assigning individual LEDs to sense the different ranges of touch and pressure. The capacitance range (<20pF–600pF<) facilitates the sensor to use in touch-sensitive multimodal switching and physiological monitoring where tactile information can create smart textile system intelligence.

Wireless graphene-enabled wearable temperature sensor

E-textile is an emerging technology which takes the advantages of material science, electronic engineering and wireless communications. We present a pilot study on smart textile system. Our study aims at developing a graphene temperature sensor and its interfacing with a commercial wireless sensor node providing the graphene sensor with processing and wireless communication capabilities. Flexible planar structure sensor was fabricated using CVD-processed single-layer graphene following its transfer to the polyvinyl chloride substrate by hot lamination method. For calibrating the graphene temperature sensor we connect it in series with a calibrated resistor and to the calibrated power source (battery). Afterwards we measure the sensor resistance via the analogue-to-digital converter of wireless sensor node, process the data and send it to the user over wireless channel.

Smart Shirts for Monitoring Physiological Parameters: Scoping Review.

BackgroundThe recent trends of technological innovation and widescale digitization as potential solutions to challenges in health care, sports, and emergency service operations have led to the conception of smart textile technology. In health care, these smart textile systems present the potential to aid preventative medicine and early diagnosis through continuous, noninvasive tracking of physical and mental health while promoting proactive involvement of patients in their medical management. In areas such as sports and emergency response, the potential to provide comprehensive and simultaneous physiological insights across multiple body systems is promising. However, it is currently unclear what type of evidence exists surrounding the use of smart textiles for the monitoring of physiological outcome measures across different settings.ObjectiveThis scoping review aimed to systematically survey the existing body of scientific literature surrounding smart textiles in their most prevalent form, the smart shirt, for monitoring physiological outcome measures.MethodsA total of 5 electronic bibliographic databases were systematically searched (Ovid Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, Scopus, Cumulative Index to Nursing and Allied Health Literature, and SPORTDiscus). Publications from the inception of the database to June 24, 2019 were reviewed. Nonindexed literature relevant to this review was also systematically searched. The results were then collated, summarized, and reported.ResultsFollowing the removal of duplicates, 7871 citations were identified. On the basis of title and abstract screening, 7632 citations were excluded, whereas 239 were retrieved and assessed for eligibility. Of these, 101 citations were included in the final analysis. Included studies were categorized into four themes: (1) prototype design, (2) validation, (3) observational, and (4) reviews. Among the 101 analyzed studies, prototype design was the most prevalent theme (50/101, 49.5%), followed by validation (29/101, 28.7%), observational studies (21/101, 20.8%), and reviews (1/101, 0.1%). Presented prototype designs ranged from those capable of monitoring one physiological metric to those capable of monitoring several simultaneously. In 29 validation studies, 16 distinct smart shirts were validated against reference technology under various conditions and work rates, including rest, submaximal exercise, and maximal exercise. The identified observational studies used smart shirts in clinical, healthy, and occupational populations for aims such as early diagnosis and stress detection. One scoping review was identified, investigating the use of smart shirts for electrocardiograph signal monitoring in cardiac patients.ConclusionsAlthough smart shirts have been found to be valid and reliable in the monitoring of specific physiological metrics, results were variable for others, demonstrating the need for further systematic validation. Analysis of the results has also demonstrated gaps in knowledge, such as a considerable lag of validation and observational studies in comparison with prototype design and limited investigation using smart shirts in pediatric, elite sports, and emergency service populations.

Electrospun Polyethylene Glycol/Polyvinyl Alcohol Composite Nanofibrous Membranes as Shape-Stabilized Solid–Solid Phase Change Materials

In this work, shape-stabilized solid-solid phase change materials (PCMs) were fabricated by simply electrospinning polyethylene glycol (PEG) and polyvinyl alcohol (PVA). Owing to the strong hydrogen bonds and entanglement between those molecular chains of PEG and PVA, PEG was packaged by PVA. The morphological structures, thermal stability and thermal energy storage properties of those fibers were investigated. SEM results showed that those electrospun PVA/PEG composite membranes hold a three-dimensional nonwoven web structure even the content of PEG as high as 70%. The thermal energy storage ability of those composite fibers increased with the increase of the content of PEG. The heat enthalpies of PEG/PVA = 7/3 were as high as 78.806 J/g. Moreover, those composite fibers had excellent thermal stability. After 100 heating and cooling cycles, there was almost no obvious change in the melting enthalpy and crystallization enthalpy. Those fibers still maintained good thermal regulation. The simple preparation process, low cost of raw materials and excellent stability endow the PCMs great utilization potentiality in smart textile and energy storage systems.

Ionoskins: Nonvolatile, Highly Transparent, Ultrastretchable Ionic Sensory Platforms for Wearable Electronics

AbstractThe primary technology of next‐generation wearable electronics pursues the development of highly deformable and stable systems. Here, nonvolatile, highly transparent, and ultrastretchable ionic conductors based on polymeric gelators [poly(methyl methacrylate‐ran‐butyl acrylate), PMMA‐r‐PBA] and ionic liquids (IL) are proposed. A crucial strategy in the molecular design of polymer gelators is copolymerization of PMMA and IL‐insoluble low glass transition temperature (Tg) polymers that can be deformed and effectively dissipate applied strains. Highly stretchable (elongation limit ≈850%), mechanically robust (elastic modulus ≈3.1 × 105 Pa), and deformation durable (recovery ratio ≈96.1% after 500 stretching/releasing cycles) gels are obtained by judiciously adjusting the molecular characteristics of polymer gelators and gel composition. An extremely simple “ionic” strain sensory platform is fabricated by directly connecting the stretchable gel and a digital multimeter, exhibiting high sensitivity (gauge factor ≈2.73), stable operation (&gt;13 000 cycles), and nonvolatility (&gt;10 d in air). Moreover, the skin‐type strain sensor, referred to as ionoskin, is demonstrated. The gels are attached to a part of the body (e.g., finger, elbow, knee, or ankle) and various human movements are successfully monitored. The ionoskin renders the opportunity to achieve wearable ubiquitous electronics such as healthcare devices and smart textile systems.

Classifying Diverse Physical Activities Using "Smart Garments".

Physical activities can have important impacts on human health. For example, a physically active lifestyle, which is one of the most important goals for overall health promotion, can diminish the risk for a range of physical disorders, as well as reducing health-related expenditures. Thus, a long-term goal is to detect different physical activities, and an important initial step toward this goal is the ability to classify such activities. A recent and promising technology to discriminate among diverse physical activities is the smart textile system (STS), which is becoming increasingly accepted as a low-cost activity monitoring tool for health promotion. Accordingly, our primary aim was to assess the feasibility and accuracy of using a novel STS to classify physical activities. Eleven participants completed a lab-based experiment to evaluate the accuracy of an STS that featured a smart undershirt (SUS) and commercially available smart socks (SSs) in discriminating several basic postures (sitting, standing, and lying down), as well as diverse activities requiring participants to walk and run at different speeds. We trained three classification methods—K-nearest neighbor, linear discriminant analysis, and artificial neural network—using data from each smart garment separately and in combination. Overall classification performance (global accuracy) was ~98%, which suggests that the STS was effective for discriminating diverse physical activities. We conclude that, overall, smart garments represent a promising area of research and a potential alternative for discriminating a range of physical activities, which can have positive implications for health promotion.