Elastic Fabrics Research Articles

Progressive and Asymmetrical Deadlift Loads Captured by Wearable Motion Tape Sensors

Weight training is widely adopted and highly effective for enhancing both muscular strength and endurance. A popular weightlifting exercise is the deadlift, which targets multiple muscle groups including the lower back, glutes, and hamstrings. However, incorrect technique (i.e., poor form) can slow training progress, result in asymmetrical muscle development, and cause serious injuries. The objective of this study was to validate that a self-adhesive, elastic fabric, wearable, skin-strain sensor called Motion Tape (MT) could monitor a person’s posture while performing deadlift exercises. Two pairs of Motion Tape were attached on the front and back sides of the pelvis at each posterior superior iliac spine to record muscle engagement during deadlift exercises. The results of this preliminary study confirmed that the MT identified asymmetry in muscle engagement during deadlifting repetitions. In addition, the sensors could quantify the different levels of effort exerted according to the deadlift weight load.

Matching combination of amorphous ionic hydrogel with elastic fabric enables integrated properties for wearable sensing

The combination of hydrogels and fabrics opens up significant opportunities for flexible materials, particularly in biomedicine and wearable technology. However, the weak interface caused by insufficient interactions between the different phases and the substantial modulus mismatch limit their broader application. In this research, flexible and amorphous polyvinyl alcohol (PVA) hydrogels were integrated with polar and elastic fabrics to create multifunctional composites via in-situ freeze-thawing technology. First, by incorporating antifreeze inorganic salts into the precursor solution, we effectively suppressed ice crystal growth during the cooling process, promoting a uniform and loosely aligned PVA chain structure. This led to the formation of an amorphous crosslinked network while simultaneously releasing free hydroxyl groups. These hydroxyl groups facilitate the formation of robust interfaces within the composite. In addition, an elastic fabric composed of a polyester-polyurethane fiber blend was selected. The polyester fibers, rich in carbonyl groups along their polymer chains, form strong hydrogen bonds with the free hydroxyl groups from the PVA hydrogel, creating a highly resilient interface. The polyurethane fibers contribute to a lower Young's modulus, as well as excellent elasticity and ductility, reducing the fabric's inherent stiffness and mitigating fiber pull-out failure. Further, the incorporation of CaCl2 not only created an environment rich in free ions, but also provided the amorphous structure with increasing spacing between adjacent polymer chains, facilitating the transportation of ions. Therefore, the composite exhibits adept sensing capabilities for intricate human body movements, fostering auspicious prospects in smart sensor applications.

A multifunctional and tough lotus root starch-based bio-photonic hydrogel for stretchable fabric pattern color change and water rewriting.

Photonic crystal hydrogels (PCHs) are innovative materials that translate imperceptible deformations and humidity changes into visible colors, broadening the applications of photonics in bioengineering and smart materials. To overcome poor mechanical properties of traditional PCHs limited by weak intermolecular forces, we designed a PCH with a dual-network framework comprising N-isopropylacrylamide-co-acrylamide (NIPAM-co-AM) and biomass lotus root starch (LR). Since LR is rich in hydroxyl groups, it can undergo molecular linkage entanglement with the NIPAM-co-AM hydrogel matrix, forming hydrogen bonds that significantly enhance the mechanical properties of the PCH. We have prepared PCH films capable of conveying multidimensional information about the extent and distribution of transient deformation by encapsulating magnetic photonic crystal microspheres (MPCMs) within a hydrogel matrix. The PCH films were found to have ultrafast response time (< 10 s), full-color tunable range, high spatial resolution, excellent mechanical toughness (tensile up to 0.17 MPa) and sensitivity (2.52 nm %-1), and were able to sense relative humidity (RH) from 11 % to 98 %. Equipped with a dynamically reconfigurable lattice, this dual-responsive (tensile/humidity) PCH not only facilitates the creation of water-rewritable photonic films but also holds promise for integration into structural color elastic fabrics, thereby presenting novel prospects for smart textile applications.

Subjective and fitting evaluation of a revised physical attachment interface for a passive exoskeleton chair

Passive exoskeleton chairs can alleviate fatigue, enhance efficiency, and reduce the risk of musculoskeletal diseases for workers standing for prolonged hours and have gradually been applied in recent years. In this study, by strategically distributing elastic and non-elastic fabrics, physical interfaces of the attachment system for the exoskeleton chair were revised to better adapt to bodily deformations and movements. We conducted an experiment using motion capture systems and subjective questionnaires to evaluate the performance of the initial and revised attachment systems of an exoskeleton chair worn by participants while performing multiple simulated assembly tasks. The results indicated that when wearing the revised one, some adverse effects on gait were significant reduced, as was the relative displacement of straps and discomfort in lumbar and abdominal, and system usability was improved, all of which were considered to be helpful in design to improve the performance of the attachment system in the future.

Highly Conductive and Elastic Electronic Silk Fabrics via 3D Textile Macro-design and Microscopic Plasma Activation for Personal Care and Information Interaction

Highly Conductive and Elastic Electronic Silk Fabrics via 3D Textile Macro-design and Microscopic Plasma Activation for Personal Care and Information Interaction

Cut-resistance of elastic high-performance composite yarn

Soft and lightweight personal protective equipment for civil or military use that is made of cut-resistant textiles is usually rigid and heavy, less elastic or flexible. Insertion of elastane fiber during the fabrication of rigid textiles seems to be working, but actually is not. Therefore, it presents a severe challenge in achieving an appropriate balance among elasticity, flexibility, and protection. To address this issue, an elastic cut-resistant composite yarn is fabricated by single wrapping ultra-high molecular weight polyethylene around elastic Spandex. The effects of wrapping parameters (including the twist, spindle speed, and yarn combination) on yarn elasticity and coverage are investigated to achieve a perfect wrapping, and the cut-resistance of the composite yarn is evaluated by using a self-improved AUTOGRAPH universal testing machine. It demonstrates that the cutting process of the composite yarn consists of four stages, the cut modulus and yarn elasticity are highly correlated with yarn structure and wrapping process parameters. The optimizing coverage and cut-resistance are achieved when the twist is 750 t/m, which is also with a high elastic recovery rate (79.79%) and low plastic deformation rate (10.11%). Groups of parallelized composite yarns with varying densities are fabricated by self-improved sample holders to simulate the cut-resistant weaving fabrics with different weaving densities, of which the cut-resistance is evaluated. The resistance against cutting varies significantly among different groups, which is directly proportional to their densities. Finally, two types of elastic cut-resistant fabrics with different structures are woven from fabricated elastic cut-resistant composite yarns practically. Both weft-backed weave and the double-layer weave fabrics have good flexibility and protection, of which the cut-resistance is level 1 and level 2, respectively. Thus, the composite yarn has an excellent elasticity and maintained cut-resistance, which is an ideal material for the production of highly elastic protective textiles.

Incorporating pre-stretching into electroless copper plating for conductivity improvement of elastic nylon fabric: application in ECG electrode

Incorporating pre-stretching into electroless copper plating for conductivity improvement of elastic nylon fabric: application in ECG electrode

Prediction of Thermal Conductivity of Elastic Single Jersey Knitted Fabric

ABSTRACT This work aims to derive a mathematical model that describes the thermal conductivity of the elastic single jersey knitted fabric (SJKF) based on the loop geometry and the yarn and fibers inclination on the direction of heat flow, and to assist the manufactures of elastic SJKF to predict the thermal conductivity from the fabric construction parameters. The main fabric construction parameters in this model are yarn count, loop length, and spandex weight percent. To validate the proposed model, elastic SJKF samples were produced at two different counts and five levels of loop length and spandex weight percent. The thermal conductivity of these samples was measured and compared to the predicted values from the new model rather than the previous three models (Maxwell – Eucken 2, Schuhmeister, Militky models). From the results, it could be concluded that the values of thermal conductivity from the model are very closed to the experimental values; therefore, the new model could be used to predict the thermal conductivity of elastic SJKF.

Electrical/optical dual-energy-driven MXene fabric-based heater with fast response actuating and human strain sensing

Multi-functional smart textiles are receiving a lot of attention for their tremendous application development in the fields of personal thermal management, artificial muscle, electronic skin, and human-machine interaction. For the complex use of many different smart textiles, designing a multifunctional textile that integrates personal thermal management, smart sensing, and flexible actuating is still a great challenge. Here, we decorated MXene on elastic fabrics by simple dip-coating and asymmetric Ecoflex encapsulation protocol to obtain electrical/optical dual-energy-driven wearable heaters with highly responsive actuating and strain-sensing performance. The MXene fabric-based heaters (MFHs) have high efficiency of Joule heating (Steady state temperature of 116.7 °C at 12 V) and photothermal conversion performance (180.3 °C in 60 s under the near infrared lamp irradiation, up to 57.5 °C under 600 W m–2 simulated solar irradiation). Benefiting from high electrical/optical dual-energy conversion efficiency, MFH has a fast photothermal driving effect (bending angle up to 360° in 5 s) due to the different curvature of thermal expansion on both sides of the fabric. Interestingly, MFH has the capability to monitor human strain (such as muscle and joint movements). Based on the above excellent performance, we finally believe that the MFHs have broad application prospects in the fields of all-weather body heat management, health monitoring, thermal health care, and thermal robotics.

Smart Elastic Fabric Strip Encompassing Prestrained Fiber Bragg Grating Sensors

Smart Elastic Fabric Strip Encompassing Prestrained Fiber Bragg Grating Sensors

Dual-functional thermal management textiles for dynamic temperature regulation based on ultra-stretchable spiral conductive composite yarn with 500%-strain thermal stability and durability.

Next-generation personal thermal management (PTM) textiles for daily routine environments are attracting extensive attention. However, challenges remain in developing multifunctional PTM textiles that are comfortable to wear, have motion stability and environmental adaptability. Herein, a novel design for fabricating a sandwich-structure PTM textile based on an ultra-stretchable spiral conductive composite yarn (SCCY) with strain-electric stability is proposed. An SCCY composed of carbon nanotubes (CNTs)/polyvinyl pyrrolidone (PVP)/waterborne polyurethane (WPU) and a drawn textured yarn (DTY) is fabricated through a dip-twisting and shaping process. The PVP not only facilitates the interfacial bonding between CNTs and yarn, but also constructs strong hydrogen bond interactions with WPU, resulting in improved structure stability and robust electrical performance. Benefitting from the optimized spiral and composite structure, the SCCY exhibits a fast thermal response (130 °C within 8 s), long-term durability (1500 cycles), and superior thermal stability under large deformation (ΔT/T0 ≈ 8.4%, under 500%). By assembling a stretchable electrothermal fabric based on SCCYs with an elastic fabric and thermochromic layer, temperature visualization and dynamic temperature regulation are integrated into the textile. This multifunctional PTM textile not only features dual thermal regulation modes of radiant cooling and Joule heating, but also maintains flexibility, breathability, and excellent stretchability, which provides broad application prospects in next-generation wearable devices.

Mass production of carbon nanotube fibers and hybrid yarns for high-performance helical auxetic yarn strain sensors

With the spectacular physical properties of electrical conductivity, mechanical strength and thermal conductivity, carbon nanotube (CNT) fibers are favored in many fields such as energy storage devices, sensing, electromagnetic shielding and structural reinforcement, especially in flexible sensing devices. However, the lower tensile properties of CNT fibers limit their further application in stretchable strain sensors, especially when monitoring large deformation variables. Here, large-scale continuous production of CNT fibers has achieved through floating catalytic chemical vapor deposition (FCCVD) technology. In the meantime, the CNT fibers were hybrid with Kevlar fibers to obtain hybrid CNT yarns with the strength of 168.4 MPa and the electrical conductivity of 7.78 × 104 S m−1. The strength of the hybrid CNT yarns produced by this method is higher than that of 40 count cotton yarns, which is perfectly suited for the fabrication of textile devices. Through knitting with three-dimensional elastic fabrics, the textile-based sensors exhibit promising sensing ability, washability, weather tolerance and sweat resistance, owing to the excellent physical and chemical properties of the hybrid CNT yarns. Moreover, stretchable strain sensors exhibit fast response and cycle stability, which provides unique opportunities in designing smart textiles with fast response and environmental durability.

Highly integrated smart mountaineering clothing with dual-mode synergistic heating and sensitive sensing for personal thermal management and human health monitoring

The development of multifunctional textiles is an effective strategy to improve the quality of human life. Normal single-mode heaters and strain sensors have been developed, but their low integration leads to multiple devices being installed on the garment, which greatly increases the weight of the garment and thus reduces its wearability. Here, bio-enzymatic polymerization and a simple shaking deposition method were used to prepare poly(3,4-ethylenedioxythiophene) (PEDOT) and copper(II) sulfide (CuS) onto the surface of the elastic nylon fabrics, which endowed the fabrics with excellent dual-mode heating properties and sensitive sensing properties, and used to develop highly integrated multifunctional and smart mountaineering clothing. In electro-driven heating mode, low-voltage (6 V) and high-voltage (12 V) heating can be used for joint heat therapy and active rapid deicing, respectively. In photo-driven heating mode, low intensity (0.3 sun) and high intensity (1.5 sun) heating can be used for joint heat therapy and rapid antibacterial, respectively. In addition, the fabric has the ability of dual-mode synergistic heating, and the surface temperature of the fabric can exhibit an ultra-high temperature of 137.9 °C under the external stimulation of 0.3 sun and 12 V. The fabric will greatly enhance the deicing and antibacterial efficiencies under the synergistic effect. This work provides a facile strategy for the fabrication of flexible and highly integrated multifunctional electronic devices, and therefore has great potential for the design and development of all-in-one multifunctional electronic devices such as personal thermal management, soft robotics, and human-computer interaction.

Preparation and performance of self-cleaning photothermal-induced self-healing flexible sensors

Flexible conductive materials for wearable applications have seen remarkable advancements in recent years. However, a significant challenge that must be addressed is their susceptibility to accidental mechanical damage. In this study, a self-healing superhydrophobic flexible fabric sensor by incorporating fluorinated polyurethane with fluorinated side chains and graphene modified with Fe3O4 nanoparticles. The fabric composite coating exhibited excellent hydrophobicity and self-cleaning ability, allowing easy removal of dirt and dust by rainwater or other liquids. Due to its excellent conductivity and stretch recovery properties, the composite coating can be applied as a wearable fabric sensor. The sensor demonstrates remarkable sensitivity to strain and can be used to monitor the movements of fingers, wrists, elbows, and other joints. Most importantly, the damaged fabric coating could restore surface integrity, repair conductivity, and maintain superhydrophobicity, which is attributed to the dynamic reversible nature of disulfide bonds and the induced dipole polarization effect of fluorinated side chains. Moreover, the fabric sensor exhibits stable photothermal conversion performance based on the joint effect of graphene and Fe3O4. This property provides a foundation for light-induced self-healing. The combination of a fluorine-modified self-healing polyurethane, Fe3O4 nanoparticles-modified graphene (FFNs-iaG), and an elastic fabric creates a self-healing superhydrophobic conductive fabric coating. This coating has excellent properties for various applications, enhancing the longevity and reliability of the fabric sensor. The combination of these materials greatly improves the performance of the fabric composite coating, resulting in a versatile fabric sensor with unique characteristics suitable for a wide range of applications.

Influence of print settings on conductivity of 3D printed elastomers with carbon-based fillers

Flexible, elastomeric materials for 3D printing have attracted considerable interest due to their potential application in clothing, shoe manufacturing and orthopedics. At the same time, smart clothing is also moving closer to more mainstream applications; as such, it is of considerable interest to combine both the structural and smart functions 3D printing offers in one material. While smart functionalities may be incorporated in a textile in a variety of ways (e.g. using shape-memory polymers), the use of electronic components such as sensors and actuators allow smart response to a multitude of stimuli. This necessitates the use of conductive and flexible materials that offer reliable conductivity after printing and provide optically attractive results. It is known that print conditions influence electrical properties, but while the print parameters are well researched for hard materials, there is not as much research for flexible compounds. Here, we show the influence of print speed, temperature, infill orientation, layer thickness and print mode (i.e. time between printing of successive layers). It was found that the most influential parameters are print mode, infill orientation and print temperature. The differences in electrical properties between the three materials used in this test may be explained by differences in filler content. A preliminary study into the optimization of the shape of a printed conductive line on elastic textile shows that the overall length of the printed path needs to be adapted to the maximum stretch of the textile, while shape has little influence on conductivity.

Incorporating Variable Porosity into the Determination of Effective Permeability in Interchanging Double Cloth Woven Fabrics Using Darcy's Law.

Woven fabrics are widely used for thermal protection due to their porosity, which provides thermal insulation and breathability. This research focuses on investigating the influential parameters in the thermal protective properties of layer interchanging double cloth, including the woven structure and varying yarn fineness. The properties affecting the protective properties and comfort of multilayered woven fabrics include the fabric thickness, fabric porosity, and air permeability. Darcy's law is applicable for determining the effective air permeability of woven fabrics. By understanding and controlling fabric porosity, it becomes possible to develop thermal protective clothing that combines improved comfort, cost-efficiency, and effectiveness. This study represents a novel approach for the clarification of airflow permeability behavior in complex structures of elastic multilayer woven fabrics using Darcy's law. This innovative approach expands the understanding of permeability in fabrics beyond single-layer fabrics with vertical pores or 3D fabrics used in resin injection processes.

An Anthropomorphic Robotic Hand With a Soft-Rigid Hybrid Structure and Positive- Negative Pneumatic Actuation

Anthropomorphic robotic hands are seeking to achieve key features such as multi-degree-of-freedom motion ability, bi-directional actuation, high adaptability, and sufficient stiffness. In this research, we propose a 10 active degrees-of-freedom anthropomorphic robotic hand with a soft-rigid hybrid structure and positive-negative pneumatic actuation. The fingers of the hand utilize pneumatic actuators composed of soft bellows to actuate a rigid skeleton for bending motion with unidirectional-stretchable nylon elastic fabric as a strain limiting layer. The positive-negative pneumatic actuation mimics the flexors and extensors of the human hand to implement bi-directional finger actuation. We present a prototype implementation of this robotic hand and provide a preliminary evaluation. The experimental results show that the combined positive-negative pneumatic actuation can extend the workspace of the finger and increase the finger stiffness compared to using only positive pneumatic actuation. The proposed robotic hand has good comprehensive performance (generated a blocking forceof 7.5 N, scored 7 in theKapandji test, achieved32 of the 33 grasp postures from the Feix taxonomy, and could implement 5 human grasping strategies) compared to other robotic hands in literatures.

Cloud benchmarking and performance analysis of an HPC application in Amazon EC2

Cloud computing platforms have been continuously evolving. Features such as the Elastic Fabric Adapter (EFA) in the Amazon Web Services (AWS) platform have brought yet another revolution in the High Performance Computing (HPC) world, further accelerating the convergence of HPC and cloud computing. Other public clouds also support similar features further fueling this change. In this paper, we show how and why the performance of a large-scale computational fluid dynamics (CFD) HPC application on AWS competes very closely with the one on Beskow—a Cray XC40 supercomputer at the PDC Center for High-Performance Computing - in terms of cost-efficiency with strong scaling up to 2304 processes. We perform an extensive set of micro and macro benchmarks in both environments and conduct a comparative analysis. Until as recently as 2020 these benchmarks have notoriously yielded unsatisfactory results for the cloud platforms compared with on-premise infrastructures. Our aim is to access the HPC capabilities of the cloud, and in general to demonstrate how researchers can scale and evaluate the performance of their application in the cloud.

Moving adsorption belt system for continuous bioproduct recovery utilizing composite fibrous adsorbents.

A continuous protein recovery and purification system based on the true moving bed concept is presented. A novel adsorbent material, in the form of an elastic and robust woven fabric, served as a moving belt following the general designs observed in known belt conveyors. The composite fibrous material that forms the said woven fabric showed high protein binding capacity, reaching a static binding capacity equal to 107.3mg/g, as determined via isotherm experiments. Moreover, testing the same cation exchange fibrous material in a packed bed format resulted in excellent dynamic binding capacity values (54.5mg/g) even when operating at high flow rates (480cm/h). In a subsequent step, a benchtop prototype was designed, constructed, and tested. Results indicated that the moving belt system could recover a model protein (hen egg white lysozyme) with a productivity up to 0.5mg/cm2/h. Likewise, a monoclonal antibody was directly recovered from unclarified CHO_K1 cell line culture with high purity, as judged by SDS-PAGE, high purification factor (5.8), and in a single step, confirming the suitability and selectivity of the purification procedure.

Biomimic Zwitterionic Polyamide/Polyurethane Elastic Blending Fabrics.

This study developed an epoxy-type biomimic zwitterionic copolymer, poly(glycidyl methacrylate) (PGMA)-poly(sulfobetaine acrylamide) (SBAA) (poly(GMA-co-SBAA)), to modify the surface of polyamide elastic fabric using a hydroxylated pretreatment zwitterionic copolymer and dip-coating method. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy confirmed successful grafting, while scanning electron microscopy revealed changes in the surface pattern. Optimization of coating conditions included controlling reaction temperature, solid concentration, molar ratio, and base catalysis. The modified fabric exhibited good biocompatibility and anti-biofouling performance, as evidenced by contact angle measurements and evaluation of protein adsorption, blood cell, and bacterial attachment. This simple, cost-effective zwitterionic modification technology has high commercial value and is a promising approach for surface modification of biomedical materials.