Wearable Products Research Articles

Screening Allergenic Potencies of Skin-Contact Products Using the Human-Derived THP-1 Cell Activation Test.

With the prevalence of allergic contact dermatitis (ACD) from the usage of skin-contact products, like wearable, skin care, and hair care products, screening their skin sensitizing potential is necessary, for the sake of alleviating the consequent public health impact. In the present study, a total of 77 skin-contact products classified by four categories, watch bands (WBs), skin care products (SCPs), hair care products (HCPs), and rubber gloves (RGs), were investigated, using an optimized in vitro assay of human cell line activation test (h-CLAT). Extracting the products using neutral artificial sweat simulated well the practical usage scenarios, and testing the extracts showed that 26 of them were allergy test positive, including nine WBs, six SCPs, two HCPs, and nine RGs. The allergenic response was mainly characterized by the induction of CD54 expression, and diverse paradigms of CD54 and CD86 levels were observed by analyzing dose-response curves, which could also be influenced by the compromised viability of the THP-1 cells. The data implicated the intricate regulation by different contributors to suspicious ingredients in the test samples. Altogether, a promising methodology for testing skin allergy potential was well established for commonly used commodities by neutral artificial sweat extraction coupled with h-CLAT screening. The findings would be of great help in tracing the potential allergens in practical products and improving their qualities.

COMPUTATIONAL WEARABLES DESIGN: SHOE SOLE MODELING AND PROTOTYPING

Computational wearables design is based on the integration of algorithms into the design process. The use of computational design tools offers a series of advantages in the wearable product design modelling because a complete family of products can be produced with a limited effort from the designer, while at the same time geometries with high complexity can be dealt with a manageable way. The present paper aims to create the appropriate code for modelling shoe soles. The use of a visual programming language leads to a better understanding of the produced code and aims in controlling and optimising the output models. Following the proposed methodology, 3D scanning technologies and plantar pressure diagrams are used for introducing the sole customised geometry, and then the proposed algorithm creates a variety of alternatives of the final shoe sole geometry. As a result, both the customisation and the high number of alternative designs lead to increased creativity and customer satisfaction. Due to the complexity of the geometry produced, 3D printing technologies are incorporated for the prototype implementation.

A Stretchable Electromagnetic Interference Shielding Fabric with Dual‐Mode Passive Personal Thermal Management

AbstractElectromagnetic interference (EMI) shielding fabrics are crucial in addressing the increasingly serious electromagnetic pollution. To meet wearable requirements, stretchability and thermal comfortability are often desired, but which still are challenging. Herein, a stretchable EMI shielding fabric is fabricated via electrospinning coupled with biaxial pre‐stretching spraying, in which a block stacking wrinkled silver nanowire (AgNW)/Ti3C2Tx MXene network is coated on one side of electrospun thermoplastic polyurethane (TPU)/polydimethylsiloxane (PDMS) fabric. As expected, the wrinkled structure protects conductive network from fracture during stretching process, so as to realize the strain‐invariant electrical conductivity. Thus, the fabric exhibits a stretchable EMI shielding performance of over 40 dB when subjected to 10–50% uniaxial strains or 21–125% biaxial strains. More importantly, the white TPU/PDMS side and the black AgNW/MXene side enable the fabric passive radiative cooling and heating, respectively. The cooling side exhibits high mid‐infrared emissivity (97.5%) and solar reflectance (90%), thus reducing the skin temperature by ≈4.9 °C. The heating side with high solar absorptivity (86.6%) and photothermal effect increased the skin temperature by ≈5 °C. Therefore, the fabirc with stretchable EMI shielding and Janus‐type dual‐mode personal passive thermal management is promising in future wearable products.

Highly stable aqueous carbon-based conductive ink for screen-printed planar flexible micro-supercapacitor

In this study, we have successfully developed a series of low-cost, environmentally friendly, and high-performance carbon-based conductive inks with a three-dimensional micro-nano structure through a simple dispersion and ball-milling process, offering an array of desirable characteristics. Significantly, the carbon-based conductive inks remained stable even after a 30-day settling period. Furthermore, the conductive film, produced using screen printing techniques, demonstrated an impressive conductivity of 1.99 × 103 S/m. This remarkable conductivity highlights the ability of the films to consistently maintain a robust conductivity network, even when subjected to 5000 mechanical bending/releasing tests. Expanding on the success of our carbon-based conductive inks, we harnessed their potential in the production of all-solid-state flexible Micro-supercapacitors (MSCs) with an interdigital structure, utilizing screen-printing technology. The resulting MSCs exhibited outstanding performance metrics, including a notable areal energy density of 1.47 µWh cm-2 and an area power density of 0.2 mW cm-2. Moreover, these MSCs demonstrated remarkable cycle stability, retaining 96.3% of their capacitance after 20,000 cycles. Additionally, their excellent mechanical flexibility was evident as they experienced only a minor 2.98% capacitance degradation after undergoing 5000 bending/releasing cycles. These findings highlight the enormous potential of our work in facilitating the scalable production of wearable and portable electronic products.

Memristive patch attention neural network for facial expression recognition and edge computing.

Facial expression recognition has made a significant progress as a result of the advent of more and more convolutional neural networks (CNN). However, with the improvement of CNN, the models continues to get deeper and larger so as to a greater focus on the high-level features of the image and the low-level features tend to be lost. Because of the reason above, the dependence of low-level features between different areas of the face often cannot be summarized. In response to this problem, we propose a novel network based on the CNN model. To extract long-range dependencies of low-level features, multiple attention mechanisms has been introduced into the network. In this paper, the patch attention mechanism is designed to obtain the dependence between low-level features of facial expressions firstly. After fusion, the feature maps are input to the backbone network incorporating convolutional block attention module (CBAM) to enhance the feature extraction ability and improve the accuracy of facial expression recognition, and achieve competitive results on three datasets CK+(98.10%), JAFFE (95.12%) and FER2013 (73.50%). Further, according to the PA Net designed in this paper,a hardware friendly implementation scheme is designed based on memristor crossbars, which is expected to provide a software and hardware co-design scheme for edge computing of personal and wearable electronic products.

Wearable sensing electronic devices with health monitoring function

Wearable mobile terminal (Wearable Devices) is a wearable mobile terminal that integrates sensors, wireless communication and multimedia technology into the human body. With the development of computer technology, wearable devices can perceive, record, analyze, adjust, intervene and even treat various diseases so as to maintain human health. Wearable electronic products refer to the intelligent exchange of information with the outside world using their own internal sensors and chips according to their physiological function or adaptability to the outside world. Wearable devices have been edging research in recent years, this paper introduces the characteristics of smart wearable devices, the materials currently applied, the different modes (types) of sensors, and discusses how the sensor network used for monitoring and transmitting recorded data can process the data network efficiently and accurately. In addition, as the sensor needs to consume more power to record and process the information obtained from the body, the battery life of smart wearable devices shortens. This paper summarizes some major concepts and methods related to the energy-saving of sensor components. Battery life significantly impacts the future personalization and universalization of health monitoring devices.

Customizable Metal Micromesh Electrode Enabling Flexible Transparent Zn-Ion Hybrid Supercapacitors with High Energy Density.

Emerging flexible and wearable electronic products are placing a compelling demand on lightweight transparent energy storage devices. Owing to their distinguishing features of safety, high specific energy, cycling stability, and rapid charge/discharge advantages, Zn-ion hybrid supercapacitors are a current topic of discussion. However, the trade-off for optical transmittance and energy density remains a great challenge. Here, a high-performance Zn-ion hybrid supercapacitor based on the customizable ultrathin (5µm), ultralight (0.45mg cm-2), and ultra-transparent (87.6%) Ni micromesh based cathode and Zn micromesh anode with the highest figure of merit (84843) is proposed. The developed flexible transparent Zn-ion hybrid supercapacitors reveal excellent cycle stability (no decline after 20000 cycles), high areal energy density (31.69 µWh cm-2), and high power density (512 µW cm-2). In addition, the assembled solid flexible and transparent Zn-ion hybrid supercapacitor with polyacrylamide gel electrolyte shows extraordinary mechanical properties even under extreme bending and twisting operation. Furthermore, the full device displays a high optical transmittance over 55.04% and can be conformally integrated with diverse devices as a flexible transparent power supply. The fabrication technology offers seamless compatibility with industrial manufacturing, making it an ideal model for the advancement of portable and wearable devices.

Graphite Paper-based Device for Energy Storage Application

The demand for versatile flexible energy storage device has arisen due to their potential, application in wearable and portable electronic product. This study presents the characterization of graphite paper-based capacitor and supercapacitor that are produced utilising commercially available pencils to draw a design by developing cheap, green, and reliable low profile electrical electrodes. The objectives of this study are to design graphite paper-based electrodes for energy storage application, characterize the physical properties of the electrodes and electrical properties of the device. Material characterization have been performed including morphology analysis of the electrodes using field emission scanning electron microscope (FESEM), compositional structures by using Energy dispersive X-ray spectroscopy (EDX) and chemical properties of the graphitic electrodes using Raman spectroscopy. Next, the electrical performance of the pencil drawn capacitor and supercapacitor have been performed. It is found that the Acidic G/PANI-Paper supercapacitor sample shows the best electrical performance in terms of lowest resistance with 0.59 MΩ, 1.12 MΩ, 1.8 MΩ and highest capacitance with 27.5 μF, 38.1 μF, 55.25 μF for respective 6 cm2, 8 cm2 and 10 cm2 area size. These characteristics show that the graphite-paper based device has a great potential in flexible energy storage applications.

Construction of CNT/CuS/FeOOH hierarchical composites on carbon cloth for high-performance solid-state flexible supercapacitors

Flexible supercapacitors (FSC) are ideal energy storage devices for wearable electronic products, yet longstanding constrained by the limited performance of negative materials. Rational design of multiple-component nanocomposites with hierarchical structures is an effective strategy to enhance the energy storage capacity. In this study, a high-capacitance flexible electrode was constructed through the in-situ growth of copper sulfide (CuS) nanosheets on carbon nanotubes (CNT) decorated carbon cloth (CC), followed by the electrodeposition of ferric hydroxide (FeOOH). The negative electrode (CC/CNT/CuS/FeOOH) demonstrates an exceptional areal capacitance of 1956.1 mF cm−2 at 1 mA cm−2 and excellent cycle stability. Subsequently, a corresponding FSC device was constructed by incorporating NiCo layered double hydroxide (CC/CNT/NiCo-LDH) as the positive material and KOH/polyvinyl alcohol (PVA) gel as the electrolyte. The FSC device exhibits an impressive volumetric energy density of 3.3 Wh cm−3 under the power density of 12.2 W cm−3. It also demonstrates excellent electrochemical and mechanical stability, showcasing high capacitance retention under cyclic use and bending conditions. This work presents a rational design strategy for the development of cost-effective, high-capacitance and stable flexible electrodes, which holds promising for integration into wearable electronic devices.

Drapability of 3D-Printed Auxetic Structure Textiles for Wearable Products Through the Digital Image Processing Technique

This study aimed to explore drapability of 3D-printed auxetic structure textiles with different geometries through the digital image processing technique in order to showcase their potential applications in 3D-printed wearable product development. A 13 (textile samples) × 3 (repetition) experimental research design consisting of 10 3D-printed auxetic structure textiles and three traditional lace fabrics were utilized in this study. The findings indicate that 3D-printed multi-angular auxetic structures exhibited the highest level of drapability followed by sinusoidal and triangular auxetic structures; these multi-angular structure textiles with draping coefficient ranging from 26.82% to 31.43% have a great potential to simulate traditional lace-like fabrics. A statistically significant correlation also was found between drapability and weight of 3D-printed auxetic structure textiles. This study demonstrates a true potential of 3D-printed auxetic structure textiles as alternatives of traditional lace textiles and their application in the wearable product development.

A multifunctional helical fiber operated in non-contact/contact dual-mode sensing aiming for HMI/VR applications

The demand for information exchange between humans and machines or virtual spaces is growing rapidly. However, traditional contact sensing makes the spread of bacteria and viruses, and single sensing also limits the development. Hence, as an innovative product, a non-contact/contact dual-mode sensor has to come into being, which consists of stretchable bacterial cellulose (BC)-BC/graphene (Gr) helical fibers. The helical fiber with a sheath-core structure, and the degradable BC as the sheath and BC/Gr as the core, which exhibit a tensile strength of 113 MPa and elongation at a break of 477%. Under non-contact mode, the capacitance change (ΔC/C0) arrives to –0.6 (–60%) when the approaching distance is 0.5 cm, and the remote communication through capacitance changes when it is sewn on the lab-gown as a wearable wireless non-contact phone. Under contact mode, action guidance and detection are achieved successfully through interaction with virtual space. All in all, this work will lead to a new era of non-contact human-machine interfaces (HMI) and dual-mode sensors, providing a solid research foundation and leading thinking for wearable electronic products that require non-contact or multi-function Internet of Things (IoT) and virtual reality (VR) field.

PVF composite conductive nanofibers-based organic electrochemical transistors for lactate detection in human sweat

The detection of lactate and other bioactive molecules is of great significance in biological research, medical testing, and environmental monitoring. Organic electrochemical transistors are a kind of biosensor devices, which can convert biological signals into electrical signals. In recent years, fiber-based organic electrochemical transistors (FECTs) provide a new approach for the construction of flexible wearable biosensors, promoting greatly the development of flexible wearable electronic products. In this study, a multilayer composite electrode was first prepared by incorporating MXene and PEDOT:PSS onto electrospun oriented polyvinyl formal (PVF) nanofiber bundle, and then assembled into FECT with high sensitivity and selectivity. Meanwhile, a wearable real-time monitoring platform was built to detect the lactate concentrations in human sweat. The results showed that MXene could act as a bridge between PEDOT:PSS and PVF, and the sensing performance of PVF/MXene/PEDOT:PSS-based FECT was enhanced obviously. It had a wide linear response range of 1 nM-100 mM, a sensitivity of 0.442 NCR/decade, a quick response time of 0.5 s, a low detection concentration, an excellent reproducibility, and a superior anti-interference characteristic. Therefore, this work provided more possibilities for the development of wearable biosensor.

Photothermoelectric fabric devices based on poly-3,4-ethylene dioxythiophene nanowires with composite nanophase boundary structures for solar energy and water vapor harvesting

At present, the thermoelectric eutectic tuning of thermoelectric materials remains a great challenge, so in this paper, polydopamine (PDA) was deposited on polypropylene (PP) to build up the gradient structure before spraying poly(3,4-ethylenedioxythiophene) nanowires (PEDOT nw), and then low-temperature interfacial polymerization technique was carried out to deposit PEDOT again to obtain the nano-phase-boundary-structured photothermoelectric fabrics. The presence of an energy filtration system at the interface of the two phases enhances the Seebeck coefficient, and hence the power factor, of the organic conducting polymer PEDOT. Subsequently, a photothermoelectric fabric (PA-PEDOT nw-Ty) has been obtained by introducing (polypyrrole) PPy as a photothermal layer, and finally a wet and dry photothermoelectric fabric device prepared by assembling with silver-functionalized polypropylene fabric (PP–Ag). The photothermoelectric fabric device can output 4.5 mV under 500 W of sunlight in the dry state, while the wet state photothermoelectric fabric device not only outputs 65.4 mV, but also evaporates 4 g of water within 1 h. Therefore, this study not only realizes the continuous conversion of photothermal to thermoelectric power, but also solar energy harvesting and solar vapor evaporation, which is a key step towards smart wearable products.

Health Monitoring System from Pyralux Copper-Clad Laminate Film and Random Forest Algorithm.

Sensor technologies have been core features for various wearable electronic products for decades. Their functions are expected to continue to play an essential role in future generations of wearable products. For example, trends in industrial, military, and security applications include smartwatches used for monitoring medical indicators, hearing devices with integrated sensor options, and electronic skins. However, many studies have focused on a specific area of the system, such as manufacturing processes, data analysis, or actual testing. This has led to challenges regarding the reliability, accuracy, or connectivity of components in the same wearable system. There is an urgent need for studies that consider the whole system to maximize the efficiency of soft sensors. This study proposes a method to fabricate a resistive pressure sensor with high sensitivity, resilience, and good strain tolerance for recognizing human motion or body signals. Herein, the sensor electrodes are shaped on a thin Pyralux film. A layer of microfiber polyesters, coated with carbon nanotubes, is used as the bearing and pressure sensing layer. Our sensor shows superior capabilities in respiratory monitoring. More specifically, the sensor can work in high-humidity environments, even when immersed in water-this is always a big challenge for conventional sensors. In addition, the embedded random forest model, built for the application to recognize restoration signals with high accuracy (up to 92%), helps to provide a better overview when placing flexible sensors in a practical system.

Customized Design for Ergonomic Products via Additive Manufacturing Considering Joint Biomechanics

This paper presents a customized design method for ergonomic products via additive manufacturing (AM) considering joint biomechanics. An ergonomic customized design model can be built based on kinesiology involving human joint biomechanics. Manifolds of the human bone can be reconstructed from X-rays, computed tomography (CT), magnetic resonance imaging (MRI), and direct 3D scanning. The conceptual and detailed design of customized products were implemented on ergonomic shoes and insoles. A lightweight lattice structure with variable porosity was generated via structural topology optimization for an ergonomic customized design. Notably, the upper surface of the custom-made insole may adhere perfectly to the plantar surface of the patient, resulting in a lower peak plantar pressure. Finite element analysis (FEA) can be employed to simulate the static or dynamic biomechanical characteristics. The conceptual ergonomic products were forwarded to the machine and fabricated via AM, driven by visual digital twin techniques. The experiments proved that a customized design suitability method for wearable ergonomic products via 3D printing is specifically tailored to the rehabilitation needs of individual customers, while consuming the least cost, time, and materials.

In-situ twisted spiral fiber with tree-ring like structure for joule heating, photothermal and humidity sensing

Smart fibers are increasingly becoming an optimal material for producing the next generation of flexible wearable electronics. However, balancing practical functionality and comfort remains a major challenge at this stage. Herein, we have prepared a bacterial cellulose (BC)/MXene-30% composite fiber using an in-situ twisting method, as this fiber possessed excellent conductivity (4050 S/m) and mechanical strength (108 Mpa). In addition, this BC/MXene spiral fiber has excellent joule heating and photothermal performance, which can be rapidly heated up to 70 °C within 25 s under a low voltage of only 9 V. They also have a stable and repeatable light-induced heating capability under 250 W infrared light. This new fiber material has a simple preparation process and versatile functional characteristics, which broadens its application in the fields of intelligent hyperthermia, respiratory monitoring, water level warnings and so on. The BC/MXene spiral fiber exhibited in this work is expected to provide a powerful database and theoretical reference for the next generation of flexible wearable electronic products.

Optimizing the gradient stress sandwich structure thin-film encapsulation for super flexible organic light-emitting devices

To enable organic light-emitting diodes (OLEDs) to be rolled and folded, we need a flexible encapsulation layer that can protect organic materials and metal electrodes that are susceptible to moisture and oxygen. Thin films that encapsulate organic electronic devices need to have excellent mechanical properties to prevent cracks during bending. Using plasma-enhanced chemical vapor deposition (PECVD) and other techniques, we fabricated high-density, stress gradient sandwich-structured films and studied the residual stress of deposited films on encapsulating films and their effect on delamination and cracking. We found that by adjusting the H2/N2 gas ratio and optimizing the Si:N:H ratio of PECVD SiNx:H films, denser, more etch-resistant, higher compressive stress and lower hydrogen content films can be deposited, thereby enable better flexible thin film encapsulation (TFE). We also deposited an inorganic/organic/inorganic sandwich structure film and utilized stress gradient changes to relieve the tensile stress on the outer film during bending. After standardized testing, the OLED with the stress gradient encapsulation structure has no dark spots after bending 10 000 times (bending radius 2 mm). This technique can be used in flexible TFE for various organic devices, showing promising applications in bendable and wearable products.

Stretchable Sensors: Novel Human Motion Monitoring Wearables.

A human body monitoring system remains a significant focus, and to address the challenges in wearable sensors, a nanotechnology-enhanced strategy is proposed for designing stretchable metal-organic polymer nanocomposites. The nanocomposite comprises reduced graphene oxide (rGO) and in-situ generated silver nanoparticles (AgNPs) within elastic electrospun polystyrene-butadiene-polystyrene (SBS) fibers. The resulting Sandwich Structure Piezoresistive Woven Nanofabric (SSPWN) is a tactile-sensitive wearable sensor with remarkable performance. It exhibits a rapid response time (less than three milliseconds) and high reproducible stability over 5500 cycles. The nanocomposite also demonstrates exceptional thermal stability due to effective connections between rGO and AgNPs, making it suitable for wearable electronic applications. Furthermore, the SSPWN is successfully applied to human motion monitoring, including various areas of the hand and RGB sensing shoes for foot motion monitoring. This nanotechnology-enhanced strategy shows promising potential for intelligent healthcare, health monitoring, gait detection, and analysis, offering exciting prospects for future wearable electronic products.

Gender and the Diversity of the Human Body as Challenges for the Inclusive Design of Wearable Technology

Particularly since the 1990s, there has been an active discussion on inclusive design and on the possibility of designing products that would be suitable for every kind of user. Wearable technology products that need to be in close contact with the user’s skin to function must be a good fit for the user’s body. As wearable technology has transitioned from a specialty of the “quantify-yourself” movement to a widespread, everyday item, the companies that create these products compete to appeal to ever-larger user groups. This study investigates how product designers in wearable technology companies interpret the idea of inclusive design when developing their products to fit large and diverse groups of users. Drawing on four case studies, this research shows how the diversity of the human body poses practical challenges for inclusive design. Yet, the findings also show that in addition to the biological differences between human bodies, inclusive design is also influenced by cultural understandings of gender.

Using wearable technological devices to improve workplace health and safety: An assessment on a sector base with multi-criteria decision-making methods

In occupational health and safety, it is important to use personal protective equipment that reduces or prevents injury to employees during an accident. Advanced sensors and computing technologies that can be worn on the body to create, store and transmit data during daily activities are wearable technology products. These products also make significant contributions to employee health and safety. The use of wearable technologies, which are very important in creating a safe work environment, is seen as a promising solution in contributing to the reduction of accidents and increasing industrial efficiency by increasing employee safety, reducing hazards and risks in sectors where occupational accidents are common.The study, it is aimed to prioritize the use of wearable technology devices in sectors that have potential risks that may cause fatigue, injury, error, and accident of employees due to labor-intensive and challenging tasks. Within the scope of this target, five alternatives and eight criteria were determined in line with the literature research and expert opinions. The criteria weights were determined by the AHP method, and the ranking of the alternatives was made by the AHP and PROMETHEE methods. Alternatives are listed as construction, mining, agriculture, textile, and chemistry. The increase in the use of wearable technology devices in the leading sectors in terms of work accidents and occupational diseases will open a new door to occupational safety and health management in the sectors and will significantly reduce health and safety problems.