Search Results (47)

A crucial factor when developing e-textiles is ensuring their robustness and functionality during everyday activities, particularly washing. The ability to launder e-textile garments is not merely a matter of convenience but a necessity for widespread adoption. Incorporating electronics into textiles can lead to damage due to mechanical and chemical stresses, which most electronics are not designed to withstand. This work focuses on electronic yarn technology (e-yarn), in which electronic functionality is added to textiles by embedding small electronic components into a flexible yarn-like structure. First, the component is soldered onto thin conductive wires. The soldered component is then enclosed in a protective polymer resin (micro-pod). Micro-pods have different diameters depending on the size of the embedded electronic component. The ensemble is finally covered in a textile sheath. This study focuses on the wash durability of e-yarns integrated with textiles in three different ways: embroidered onto the surface of a woven fabric, within a knitted channel in a knitted fabric, and woven as a weft yarn. Further, the work studied the impact of using different sizes of micro-pods on the e-yarns’ wash durability. Ultimately, good wash durability was observed under all testing conditions. Full article

The interest in flexible and wearable electronics is increasing in both scientific research and in multiple industry sectors, such as medicine and healthcare, sports, and fashion. Thus, compatible power sources are needed to develop secondary batteries, fuel cells, supercapacitors, sensors, and dye-sensitized solar cells. Traditional liquid electrolytes pose challenges in the development of textile-based electronics due to their potential for leakage, flammability, and limited flexibility. On the other hand, gel electrolytes offer solutions to these issues, making them suitable choices for these applications. There are several advantages to using gel electrolytes in textile-based electronics, namely higher safety, leak resistance, mechanical flexibility, improved interface compatibility, higher energy density, customizable properties, scalability, and easy integration into manufacturing processes. However, it is also essential to consider some challenges associated with these gels, such as lower conductivity and long-term stability. This review highlights the application of gel electrolytes to textile materials in various forms (e.g., fibers, yarns, woven, knit, and non-woven), along with the strategies for their integration and their resulting properties. While challenges remain in optimizing key parameters, the integration of gel electrolytes into textiles holds immense potential to enhance conductivity, flexibility, and energy storage, paving the way for advanced electronic textiles. Full article

This paper presents the research and numerical modeling of heat flow through a textile heat sink (THS). The aim of this research is to create a numerical model of a THS that not only simulates the thermal behavior of knitted fabrics, which are used to construct a THS, but also serves as a predictive tool for the heat flow coming from different devices, thus increasing thermal management safety. By integrating modeling tools with textile engineering, this study contributes valuable insights to the development of effective passive cooling solutions for textronics applications, e.g., in thermal management in the military or air space sectors. THS is a support tool for multilayer insulation (MLI) blankets in space satellites, used to maintain the insulation performance of MLI to retain the extremely low temperature of satellite sensors or fuel tanks. The textile radiator made of spacer knitted 3D fabric consists of monofilament yarns covered with aluminum. THS samples were made on the HD 6/20-65 EL machine of Karl Mayer, with the calibration number E12. Numerical modeling was performed using ANSYS software. The numerical simulations of the temperature gradient presented the heat flow for source temperatures of 50 °C and 70 °C for different values of air velocity. Full article

This paper introduces a novel approach to fabricating textile microwave transmission lines through knitting techniques. These textile-based transmission lines, capable of transmitting high-frequency signals between wearable transceivers and antennas, offer significant potential for the development of advanced wearable electronics. By leveraging a single technological process, our proposed method enables the creation of flexible and wearable devices. To demonstrate the feasibility of this approach, we present the design and numerical modeling of a microstrip line operating within the gigahertz frequency range. A prototype structure was fabricated and experimentally characterized, revealing moderate attenuation of less than 5 dB for frequencies below 2.5 GHz. However, a major challenge in the field of wearable electronics is the real-time applicability of such devices. Our work aims to address this challenge by providing a flexible and scalable solution for integrating wireless communication capabilities into wearable systems. Future research will focus on further optimizing the design and fabrication processes to enhance performance and minimize signal loss, ultimately enabling the realization of practical and user-friendly wearable devices. Full article

We aimed to reduce the recovery time for baseball pitchers from the established recovery period of four days to only one day. We designed a wearable and flexible arm sleeve composed of knitted nylon and a polyether–polyurea copolymer that has embedded proprietary dry electrodes that deliver a personalized microcurrent electron stream regimen as well as physiological motion sensors that provide real-time feedback for this electroceutical’s efficacy, positioning it as a revolutionary e-textile for enhancing and gauging sporting proficiency. Healables^® (Jerusalem, Israel) developed a noninvasive wearable device that docks onto its adjustable e-textile for team training and on-the-go and home-based improvement in terms of sports readiness, recovery, and performance. Full article

The textile industry, renowned for its comfort-providing role, is undergoing a significant transformation to address its environmental impact. The escalating environmental impact of the textile industry, characterised by substantial contributions to global carbon emissions, wastewater, and the burgeoning issue of textile waste, demands urgent attention. This study aims at identifying the feasibility of the future use of textile scraps in the construction and architecture industry by analysing the effect of different binders. In this study, synthetic knitted post-consumer-waste fabrics were taken from a waste market for use as a reinforcement, and different binders were used as the matrix. In the experiment phase, the waste fabrics were mixed with synthetic binders and hydraulic binders to form brick samples. The mechanical and thermal properties of these samples were tested and compared with those of clay bricks. In terms of mechanical properties, unsaturated polyester resin (UPR) samples showed the highest mechanical strength, while acrylic glue (GL) samples had the lowest mechanical strength. White cement (WC) samples showed moderate mechanical properties. Through several tests, it was observed that UPR samples showed the highest values of tensile, bending, and compressive strengths, i.e., 0.111 MPa, 0.134 MPa, and 3.114 MPa, respectively. For WC, the tensile, bending, and compressive strengths were 0.064 MPa, 0.106 MPa, and 2.670 MPa, respectively. For GL, the least favourable mechanical behaviour was observed, i.e., 0.0162 MPa, 0.0492 MPa, and 1.542 MPa, respectively. In terms of thermal conductivity, WC samples showed exceptional resistance to heat transfer. They showed a minimum temperature rise of 54.3 °C after 15 min, as compared to 57.3 °C for GL-based samples and 58.1 °C for UPR. When it comes to polymeric binders, UPR showed better thermal insulation properties, whereas GL allowed for faster heat transfer for up to 10 min of heating. This study explores a circular textile system by assessing the potential of using textile waste as a building material, contributing to greener interior design. This study demonstrated the usefulness of adding short, recycled PET fibres as a reinforcement in UPR composites. The use of the PET fibre avoids the need to use a surface treatment to improve interfacial adhesion to the UPR matrix because of the chemical affinity between the two polyesters, i.e., the PET fibre and the unsaturated polyester resin. This can find application in the construction field, such as in the reinforcement of wooden structural elements, infill walls, and partition walls, or in furniture or for decorative purposes. Full article

Electronic textiles (E-textiles) have experienced an increase in interest in recent years leading to a variety of new concepts emerging in the field. Despite these technical innovations, there is limited literature relating to the testing of E-textiles for some of the fundamental properties linked to wearer comfort. As such, this research investigates four fundamental properties of E-textiles: air permeability, drape, heat transfer, and moisture transfer. Three different types of E-textiles were explored: an embroidered electrode, a knitted electrode, and a knitted structure with an embedded electronic yarn. All of the E-textiles utilized the same base knitted fabric structure to facilitate a comparative study. The study used established textile testing practices to evaluate the E-textiles to ascertain the suitability of these standards for these materials. The study provides a useful point of reference to those working in the field and highlights some limitations of existing textile testing methodologies when applied to E-textiles. Full article

Double-layered textile sweat-absorbing underarm pads with a natural antimicrobial treatment can be used to solve the problem of the wetness sensation in the case of increased physical activity or hyperhidrosis. In addition, changeable antimicrobial active underarm pads help to decrease the number of clothing washings, i.e., reducing water consumption and pollution. Another aspect of sustainability is that the underarm pads can be produced from clothing production waste. The moisture absorption capability of six hydrophilic cellulose-based knitted fabrics and two hydrophobic synthetic woven fabrics was investigated. It was found that the best result for next-to-skin moisture absorption and next-to-clothing protection against moisture penetration was achieved by using a double-layered underarm pad composed of a cotton-based fleece knitted structure in the next-to-skin layer and a very thin and tight 100% PA woven fabric in the outer layer. Four samples of impregnated liquid with herbal extracts and essential oils were prepared, and antimicrobial activity was evaluated using the discus method. Textile impregnated with tea tree essential oil, nutmeg, and birch extracts had the highest antimicrobial activity against Gram-positive bacteria—Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus cereus. Full article

Functional electrical stimulation (FES) aims to improve the gait pattern in cases of weak foot dorsiflexion (foot lifter weakness) and, therefore, increase the liveability of people suffering from chronic diseases of the central nervous system, e.g., multiple sclerosis. One important component of FES is the detection of the knee angle in order to enable the situational triggering of dorsiflexion in the right gait phase by electrical impulses. This paper presents an alternative approach to sensors for motion capture in the form of weft-knitted strain sensors. The use of textile-based strain sensors instead of conventional strain gauges offers the major advantage of direct integration during the knitting process and therefore a very discreet integration into garments. This in turn contributes to the fact that the FES system can be implemented in the form of functional leggings that are suitable for inconspicuous daily use without disturbing the wearer unnecessarily. Different designs of the weft-knitted strain sensor and the influence on its measurement behavior were investigated. The designs differed in terms of the integration direction of the sensor (wale- or course-wise) and the width of the sensor (number of loops) in a weft-knitted textile structure. Full article

Flexible capacitive pressure sensors have been widely developed to be used in electronic skin, human movement, real-time health monitoring, and human–machine interactions. This paper introduces a Flexible Capacitive Pressure Sensor Array (FCPSA) that is designed to reduce costs and can be integrated into commercial textiles, e.g., insoles. The FCPSA comprises a five-layer sandwich structure. The bottom layer is a conductive layer, operating both as interference shielding and the common electrode for the distributed capacitive sensor array, with a polyester double-jersey-knitted fabric acting as the dielectric material, segmented carbon woven fabrics as the top electrodes in the array, a polymeric film for electrical and moisture isolation, and a foam placed on the surface to improve comfort. A system including three CPSs and a data acquisition device is established for real-time pressure monitoring. In the range of 0–100 kPa, a capacity increase of 35% is observed, the linearity of which depends on the elastic behavior of the dielectric layer. This sensor array can be utilized for real-time pressure monitoring. Full article

This study examines the durability of stretchable conductive tracks on knitted fabrics. Two knitted fabrics with three designs of conductive tracks are tested to assess the fabric strain release and resistance change after a 50% elongation. The optimised design, made with all needle back jacquard knitting with sinusoidal conductive tracks, exhibits a 4% increase in fabric length and a 0.23 Ω (38.9%) increase in resistance. This e-textile is used to fabricate a sleeve with integrated functional electrical stimulation (FES) for stroke rehabilitation. The optimised electrode pattern, designed for stroke arm/hand rehabilitation, was achieved through co-design with stroke survivors and healthcare professionals. The prototype was tested on stroke survivors to assess stimulation comfort and ease of use. Tests have confirmed that the electrode sleeve (e-sleeve) is comfortable to wear and that stroke survivors are able to don and doff the e-sleeve using a single hand, facilitating independent home use. Full article

Fabrics have been recognized as a necessary component of daily life due to their involvement in garments, home textiles, and industrial textiles. The mechanical performance of textiles was considered essential to meet the end-user requirements for strength and durability. The purpose of this work was to provide an overview of the textile structures and tensile strengths of woven textiles. Different types of textile structures, depending on the weaving methods (woven, braided, knitted, non-woven) and the most common architectures of woven fabrics (plain weave, twill and sateen), were presented. Common materials constituting the textiles’ structures and a comparison in terms of the density, Young’s modulus and tensile strength between natural (plant-based, animal-based, and mineral-based) and synthetic fibers were reported. The mechanical properties of woven textiles were presented for neat and coated textiles, primarily in terms of the tensile strength. Depending on the cases, typical regions in the load–displacement curve (i.e., crimp, elastic, non-linear failure, thread fracture) were highlighted. The impact of the architecture, yarn distance and size, and yarn twisting on the tensile strength of woven fabrics was then illustrated. Full article

Biopotential electrodes play an integral role within smart wearables and clothing in capturing vital signals like electrocardiogram (ECG), electromyogram (EMG), and electroencephalogram (EEG). This study focuses on dry e-textile electrodes (E1–E6) and a laser-cut knit electrode (E7), to assess their impedance characteristics under varying contact forces and moisture conditions. Synthetic perspiration was applied using a moisture management tester and impedance was measured before and after exposure, followed by a 24 h controlled drying period. Concurrently, the signal-to-noise ratio (SNR) of the dry electrode was evaluated during ECG data collection on a healthy participant. Our findings revealed that, prior to moisture exposure, the impedance of electrodes E7, E5, and E2 was below 200 ohm, dropping to below 120 ohm post-exposure. Embroidered electrodes E6 and E4 exhibited an over 25% decrease in mean impedance after moisture exposure, indicating the impact of stitch design and moisture on impedance. Following the controlled drying, certain electrodes (E1, E2, E3, and E4) experienced an over 30% increase in mean impedance. Overall, knit electrode E7, and embroidered electrodes E2 and E6, demonstrated superior performance in terms of impedance, moisture retention, and ECG signal quality, revealing promising avenues for future biopotential electrode designs. Full article