Nanofiber Yarns Research Articles

High-Strength and Conductive Electrospun Nanofiber Yarns

In electrospinning, nanofibers are frequently produced in nonwoven web form. Their poor mechanical properties (below 100 MPa) and difficulty in tailoring the fibrous structure have restricted their applications. However, advanced materials must be highly resistant to both deformation and fracture. By combining electrospinning technology with stretching, we have overcome this disadvantage and demonstrated a polyacrylonitrile nanofiber yarn with a tensile strength of 743 ± 20 MPa. The nearly perfect uniaxial orientation of the fibrils under the stretching process is crucial for the remarkable mechanical properties of the yarn. Additionally, the nanofiber yarn was functionalized by a dip-coating process with silver nanowires (AgNWs), imparting conductive properties. This conductive, high-strength nanofiber yarn demonstrates practical applications in flexible and wearable devices. The presented strategy is versatile and can be adapted to create other high-performance nanofiber yarns, with potential uses in fields such as biomedicine and smart textiles.

Modeling and characterization of the mechanical properties of nanofiber yarn

This study investigates the mechanical properties and unique structural features of nanofiber yarns produced via electrospinning. Through experimental, analytical, and numerical methods, the tensile behavior of the yarns was evaluated. Nanofiber yarns, composed of submicron-diameter fibers, exhibit a significantly larger surface area and stronger fiber interactions compared to conventional yarns. These structural characteristics result in a marked improvement in mechanical properties, with the nanofiber yarns showing a 25% increase in stiffness and a 15% enhancement in damping capacity. A three-element viscoelastic model was applied to accurately describe the nonlinear tensile response of the yarns, with a high correlation to experimental data (R2 > 0.999). Furthermore, nanofiber yarns demonstrated superior thermo-mechanical stability, with a tan δ peak observed at 108 °C, compared to 100 °C for conventional yarns. These findings suggest that nanofiber yarns are promising candidates for applications in tissue engineering, filtration, energy storage, and other high-performance fields. The research provides a solid foundation for further optimization of nanofiber yarns to fully exploit their mechanical potential.

Yarn-Based Degradable Janus PPDO Fabric for Multifunctional Applications.

The growing high standard of people's wear has put forward requirements for fabrics, and multifunctional fabrics have been developed precisely in response to the requirements of the times. However, the incineration of waste fabrics produces a large amount of pollutants, resulting in a massive waste of resources and environmental pollution. Herein, the degradable nanofiber yarns (NYs) with self-cleaning properties were fabricated by in situ growth of SiO2 nanoparticles on the surface of the electrospun poly(p-dioxanone) (PPDO) NYs using the Stöber method. Then, the PPDO NYs were blended with carbon fibers and the PPDO/SiO2 NYs with themselves to form the Janus PPDO fabrics, respectively. The Janus PPDO fabric offered asymmetric wettability and dual personal thermal management properties. The PPDO/C side of the Janus PPDO fabric provided 65.8 °C at 1.5 V or 58.5 °C under one sunlight intensity for radiative heating. The PPDO/SiO2 side exhibited high solar reflectivity (81.8%) and mid-infrared (MIR) emissivity (99.1%), which reduced the skin temperature by 4.6 °C, resulting in radiative cooling. Moreover, the Janus PPDO fabrics display an excellent electromagnetic interference (EMI) shielding performance (53.3 dB). Therefore, yarn-based degradable Janus fabric has a promising future in multifunctional wearable products.

Thermally robust hierarchical nanofiber triboelectric yarns for efficient energy harvesting in firefighting E-textiles

Textile-based triboelectric nanogenerators (TENGs) face challenges in achieving high performance and fulfilling functional requirement for special applications. This paper presents the development of a high-performance, thermally robust hierarchical polyimide (PI) nanofiber triboelectric yarns with a charge-trapping interlayer for application in firefighting E-textiles. The hierarchical nanofiber yarns, comprising a stainless-steel core electrode, a PI/MXene interlayer and PI outer tribo-layer, exhibit enhanced triboelectric performance due to the charge-trapping capabilities of MXene, which preventing the recombination of triboelectric and induced charges. When the MXene content in the charge-trapping interlayer reached 1 wt%, the corresponding TENG achieved its optimal output performance, with an output voltage of 153 V and a current of 13.13 μA and a peak power density of 0.84 W/m2 under optimal conditions. It also demonstrates exceptional thermal stability, maintaining stable output at temperatures up to 400 °C. The integration of the TENG into E-textiles enables real-time monitoring of firefighters’ physical activities and location tracking, significantly enhancing their safety and operational efficiency in fire scenarios. Additionally, the TENG powers electroluminescent yarns, improving visibility in dense smoke and dust environments. This research opens new avenues for the application of smart wearable systems in high-temperature environments, providing effective strategies for ensuring the safety of firefighters in fire rescue operations.

Thermoresponsive nanofiber yarns for water harvesting enhanced by harp system

The escalating global water crisis necessitates innovative approaches to developing sustainable water resources. Fog water collectors with variable surface wettability offer controlled fog harvesting in water-scarce regions. This study develops thermoresponsive fog collecting materials by electrospinning poly(N-isopropylacrylamide)-polyvinylidene fluoride (PNIPAm-PVDF) into yarns that are transformed into harp-like structures for enhanced water harvesting rate. Both meshes and harps using electrospun membranes exhibit the remarkable ability to transition between hydrophilic and hydrophobic wetting states at temperatures below the lower critical solution temperature (LCST). Hydrophilic and hydrophobic surfaces play distinct roles in fog water collection. Hydrophilic surfaces have a high affinity for water and enables droplet capture. Hydrophobic surfaces help the removal of aggregated water droplet and fog water collection. The highest water collection rate obtained with the electrospun PNIPAm-PVDF harp was 1415 ± 7.0 mg·cm−2 h−1. The water harvesting system based on the electrospun PNIPAm-PVDF harps exhibits a 485 % increase in water collection compared to the standard meshes made from the same material, emphasizing their potential for significantly improving the overall rate in fog water harvesting applications.

Electrospun Aligned Nanofiber Yarns Constructed Biomimetic M‐Type Interface Integrated into Precise Co‐Culture System as Muscle‐Tendon Junction‐on‐a‐Chip for Drug Development (Small Methods 9/2024)

Electrospun Aligned Nanofiber Yarns Constructed Biomimetic M‐Type Interface Integrated into Precise Co‐Culture System as Muscle‐Tendon Junction‐on‐a‐Chip for Drug Development (Small Methods 9/2024)

Design and fabrication of highly aligned poly(l‐lactide‐co‐ε‐caprolactone) nanofiber yarns and braided textiles

AbstractAn approach that combines a modified electrospinning method with thermal stretching post‐treatment is designed to fabricate poly(l‐lactide‐co‐ε‐caprolactone) (PLCL) electrospun nanofiber yarns (ENYs). The nanofiber diameter in the PLCL ENYs is found to present an increasing trend with the increasing of polymeric concentration. When the PLCL concentration reaches 13% (w/v), the as‐generated ENYs show bead‐free and uniform nanofibrous structure. Then, a thermally stretching technique is applied to process the primarily‐obtained PLCL ENYs. When the stretching temperature is set as 60 °C, the thermally‐stretched PLCL ENYs present superior fiber orientation and notably enhanced crystallinity, thus resulting in dramatically increased mechanical properties. Finally, the thermally stretched PLCL ENYs are further processed into braided fabrics, and their mechanical properties are found to possess an obviously increased trend with the increasing of ENY numbers, demonstrating the adjustment feasibility of the mechanical properties of ENY‐based textiles by controlling the ENY numbers. Importantly, the in vitro cell studies demonstrate that the ENY‐based braided textiles significantly support the adhesion and proliferation of human dermal fibroblasts (HDFs). In all, the present study provides an easily‐handling strategy to fabricate high performance PLCL ENYs, which shows promising future for the generation of advanced biomedical textiles.

A super-elastic wearable strain sensor based on PU/CNTs yarns for human-motion detection

Yarn-based strain sensors increasingly garner attention for their potential applications in intelligent wearable electronic devices. Developing highly elastic conductive composite yarns and integrating them into fabrics poses a significant challenge in manufacturing flexible electronic devices. In this study, a polyurethane (PU)/carbon nanotubes (CNTs) composite nanofiber yarn was successfully and continuously prepared using a simple conjugate spinning technique. The resulting yarn exhibited excellent mechanical properties, with a high tensile strength of up to 56.7 MPa and an elongation at break of 504 %. A yarn with a dual conductive network was created using CNTs ink dip-coating. It demonstrated excellent conductivity (8.77 S/cm), exceptional linear variation, and reusability. The sensor remained stable after 1000 cycles of testing, exhibiting a relative electrical resistance change of up to 594 % under a strain of 350 %. Additionally, taking advantage of the inherent knittability of one-dimensional yarn structures, a susceptible wearable textile-type strain sensor was successfully developed using textile knitting technology. This sensor can be directly attached to the surface of the human body for real-time monitoring of human body dynamics. This sensor showcases significant promise for use in flexible, intelligent, wearable electronic devices.

Facile conjugate electro-spinning to achieve nanofiber yarns with concurrent color-tunable photoluminescence and tailored superparamagnetism

In this work, we have successfully fabricated hetero-structured nanofiber yarns (NFYs) with a conjugate electro-spinning technique, integrating a dual-functional capability of tunable color photoluminescence and tailored superparamagnetism. These hetero-structured NFYs are comprised of [Eu(BA)3phen + Tb(BA)3phen]/polyacrylonitrile (PAN) photoluminescent nanofibers (NFs) and Fe3O4/PAN superparamagnetic NFs, which allow for the effective isolation of dark-colored Fe3O4 nanoparticles (NPs) from rare earth complexes. This design leads to enhanced photoluminescent performance for the hetero-structured NFYs. Detailed investigations into the morphologies and performances of these NFYs were conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), fluorescence spectrophotometry, and vibrating sample magnetometry (VSM). The emitting light color, ranging from red to yellow to green, can be tuned under a specific excitation wavelength (276 nm) of ultraviolet (UV) light by regulating the proportion of rare earth complexes. Furthermore, the superparamagnetism of the NFYs can be tailored by varying the amounts of Fe3O4 NPs. The designing philosophy and preparative technique can be utilized to manufacture other polyfunctional nanomaterials.

Electrospinning of fluorescent-magnetic-conductive tri-functional nanofibrous yarns

To achieve a high integration of fluorescence, conductivity and magnetism in the yarn structure while completely avoiding direct contact of different functional substances, three types of nanofibers with different functions are integrated into a yarn to achieve enhanced perovskite quantum dots (PQDs) fluorescence, intensified conductivity and adjustable magnetism. As a case study, [CsPbBr3 PQDs/polyacrylonitrile (PAN)]//[CoFe2O4/PAN]//[polyaniline (PANI)/PAN] triple-strand nanofibers yarns (TSNYs) were innovatively designed and constructed. We also advance a facile triple-strand conjugate electrospinning technology for the first time to create this specialized nanofiber yarn. The mechanical properties of the TSNYs are controllable by adjusting the twist. TSNYs emit strong green fluorescence excited by 365-nm ultraviolet (UV) light. The magnetism and conductivity of TSNYs are respectively tunable by regulating the contents of CoFe2O4 MNPs and PANI. With the aid of the peculiar structure of TSNYs, various substances are evenly distributed in the respective nanofibers avoiding direct contact. TSNY effectively prevents the adverse effects of dark-colored magnetic and conductive substances on the fluorescent properties, and the decrease in conductivity caused by mixing insulating substances with PANI is also avoided. TSNYs exhibit 33 times higher fluorescence intensity and two orders of magnitude higher conductivity than the composite nanofibers yarns. The formation mechanism of the TSNYs is elucidated, and triple-strand conjugate electrospinning technique is established. The design ideas and fabricating techniques are instructive for fabricating poly-functional yarns. The fluorescence-magnetic-conductive yarns are potential candidates in lighting devices, biomedical imaging and electromagnetic shielding.

Spinning the Future: The Convergence of Nanofiber Technologies and Yarn Fabrication.

The rapid advancement in nanofiber technologies has revolutionized the domain of yarn materials, marking a significant leap in textile technology. This review dissects the nexus between cutting-edge nanofiber technologies and yarn manufacturing, aiming to illuminate the pathway toward engineering advanced textiles with unparalleled functionality. It first discusses the fundamentals of nanofiber assemblies and spinning techniques, primarily focusing on electrospinning, centrifugal spinning, and blow spinning. Additionally, the study delves into integrating nanofiber spinning technologies with traditional and modern yarn fabrication principles, elucidating the design principles that underlie the creation of yarns incorporating nanofibers. Twisting technologies are explored to examine how they can be optimized and adapted for incorporating nanofibers, thus enabling the production of innovative nanofiber-based yarns. Special attention is given to scalable strategies like centrifugal and blow spinning, which are spotlighted for their efficiency and scalability in fabricating nanofiber yarns. This review further analyses recently developed nanofiber yarn applications, including wearable sensors, biomedical devices, moisture management textiles, and energy harvesting and storage devices. We finally present a forward-looking perspective to address unresolved issues in nanofiber-based yarn technologies.

Comparative study of tensile behavior in micro/nanofiber-enhanced epoxy nanocomposites featuring different textile structures

Recent advancements in nanofiber production technology have opened up exciting possibilities for highly sophisticated applications in nanofiber-based structures, particularly in the realm of nanofiber yarns. These yarns serve as fundamental components in various fabric designs, encompassing woven, knitted, braided, and nonwoven patterns. Additionally, these fabrics can serve as reinforcement in nanocomposites with a polymeric matrix. This study aims to investigate the reinforcing effect of micro/nanofibers in various fabric structures, such as nonwoven, woven, and knitted fabrics. Apart from depositing micro/nanofibers, we successfully manufactured a micro/nanofiber yarn made of polyamide-6. This was achieved by employing two nozzles equipped with opposite charges and flat-tipped needles. Furthermore, we created both woven and weft-knitted fabrics using this micro/nanofiber yarn. Subsequently, we utilized nonwoven, woven, and weft-knitted fabrics to reinforce epoxy resin. The results indicated that the nanocomposite reinforced with woven fabric in the warp direction, featuring a volume fraction of 12%, exhibited the highest Young’s modulus (7500 MPa, 5.47 times more compared to epoxy) and ultimate strength (112 MPa, 5.09 times more compared to epoxy). This study represents a pioneering step towards the development of nanofiber-based reinforcements with promising potential applications.

Electrospun Aligned Nanofiber Yarns Constructed Biomimetic M-Type Interface Integrated into Precise Co-Culture System as Muscle-Tendon Junction-on-a-Chip for Drug Development.

The incorporation of engineered muscle-tendon junction (MTJ) with organ-on-a-chip technology provides promising in vitro models for the understanding of cell-cell interaction at the interface between muscle and tendon tissues. However, developing engineered MTJ tissue with biomimetic anatomical interface structure remains challenging, and the precise co-culture of engineered interface tissue is further regarded as a remarkable obstacle. Herein, an interwoven waving approach is presented to develop engineered MTJ tissue with a biomimetic "M-type" interface structure, and further integrated into a precise co-culture microfluidic device for functional MTJ-on-a-chip fabrication. These multiscale MTJ scaffolds based on electrospun nanofiber yarns enabled 3D cellular alignment and differentiation, and the "M-type" structure led to cellular organization and interaction at the interface zone. Crucially, a compartmentalized co-culture system is integrated into an MTJ-on-a-chip device for the precise co-culture of muscle and tendon zones using their medium at the same time. Such an MTJ-on-a-chip device is further served for drug-associated MTJ toxic or protective efficacy investigations. These results highlight that these interwoven nanofibrous scaffolds with biomimetic "M-type" interface are beneficial for engineered MTJ tissue development, and MTJ-on-a-chip with precise co-culture system indicated their promising potential as in vitro musculoskeletal models for drug development and biological mechanism studies.

Fabrication of nanofiber yarns via electro-blown and hang-fiber process

Continuous nanofiber yarns were prepared using the electro-blown and hanging yarn process. Unlike typical electrospinning devices, this method uniquely controls the spinning process to induce the hanging phenomenon, and the resulting hanging yarn is twisted to form nanofiber yarns. A polyvinylidene fluoride nanofiber yarn was successfully prepared using the electro-blown and hanging yarn process. Scanning electron microscopy observations confirmed that the nanofibers prepared by this method exhibited good orientation within the yarn. The results indicate that the conductivity of the polymer solution and the applied voltage are crucial for inducing the hanging yarn process, ensuring stable continuous spinning. A possible mechanism is proposed, suggesting that adjusting the solution’s conductivity and controlling the spinning voltage can utilize defects in the yarn-hanging process during spinning to prepare nanofiber yarns.

Simulation and experimental study of nanofiber yarns prepared by disc electrospinning

Conjugated electrospinning is an exciting way to prepare nanoyarns. However, all currently reported preparations of nanofiber yarns by conjugated electrospinning use needles, which can cause discontinuous yarn production due to plugging needles during the preparation process. Herein, a novel disc treated with rounded corners as the spinneret of conjugated electrospinning was developed to spin continuously twisted nanofiber yarn to overcome the existing problems. First, finite element analysis was used to optimize the parameters of the disc. The disc exhibited the optimal field strength distribution on the spinning surface when the disc rounding angle was 0.7, and the coefficient of variation value of the field strength was only 12.6%. After that, we optimized the effect of spinning parameters on yarn yield by central composite design. In addition, the impact of spinning parameters on fiber morphology was also investigated. Under the optimized parameters, it is possible to spin continuously at a 360 m/h speed for at least 1 h without breaking. This innovative approach provides a novel idea for continuously producing nanofiber yarns.

A facile method for continuous production of temperature-adaptive hyperthermal management core-sheath polyurethane nanofiber yarns based on vanadium dioxide toward commercialization

As a facile method for producing nanofiber materials, electrospinning is widely used in various fields. However, it is generally adopted for fabricating nonwoven nanofiber membranes, which limited its applications. In this study, we propose a new facile mechanism for continuous production of high-strength electrospinning nanofiber-covered yarns, which can be directly used for fabric weaving toward commercialization. After doping of vanadium dioxide(VO2), a solid–solid phase change material (PCM) with a phase change temperature close to room temperature, a smart nanofiber-covered yarn with hyperthermal management capability is obtained. Benefiting from the delicate core-sheath structure and rigorous adjustment of spinning solution composition as well as spinning parameters (including spinning voltage, solution flow rate, and spinning distance), it achieved optimal nanofiber diameter at 510 nm, and patterns sewn on polyester fabric can be lowered by up to 19 °C compared to polyester fabric. The nanofiber-covered yarn can be used for textiles such as garments and curtains, which helps reduce the tremendous energy consumed for thermal regulation.

Micro–nano hierarchical scaffold providing temporal-matched biological constraints for tendon reconstruction

Due to the limitations of tendon biology, high-quality tendon repair remains a clinical and scientific challenge. Here, a micro–nano hierarchical scaffold is developed to promote orderly tendon regeneration by providing temporal-matched biological constraints. In short, fibrin (Fb), which provides biological constraints, is loaded into poly (DL-lactide-co-glycolide) nanoyarns with suitable degradation cycles (Fb-loaded nanofiber yarns (Fb-NY)). Then further combined with braiding technology, temporary chemotactic Fb scaffolds with tendon extracellular matrix-like structures are obtained to initiate the regeneration process. At the early stage of healing (2 w), the regeneration microenvironment is regulated (inducing M2 macrophages and restoring the early blood supply necessary for healing) by Fb, and the alignment of cells and collagen is induced by nanoyarn. At the late healing stage (8 w), with the degradation of Fb-NY, non-functional vascular regression occurs, and the newborn tissues gradually undergo load-bearing remodeling, restoring the anvascularous and ordered structure of the tendon. In summary, the proposed repair strategy provides temporal-matched biological constraints, offering a potential pathway to reconstruct the ordered structure and function of tendons.

Self‐standing piezoelectric nanogenerator fabrics from ZnO‐doped PVDF nanofiber yarns

AbstractToday a wide variety of wearable electronics are in our daily lives and their uses are increasing. The development of portable, flexible, lightweight, cost‐effective, and stable devices that produce sustainable energy with renewable approaches in the field of wearable electronics, as in every field, is one of the important issues of today. According to their volume and weight, the use of nanofibers with high surface area in energy‐generating devices may bring them advantages such as lightness and higher energy density. Therefore, in recent years, researchers have focused on the development of nanofiber‐based nanogenerators that produce energy using mechanical energy in a sustainable and renewable way. In this paper, self‐standing piezoelectric nanogenerator (PENG) fabrics were obtained by developing flexible composite poly(vinylidene fluoride) (PVDF) nanofiber yarns doped with zinc oxide (ZnO) nanoparticles at different rates to provide higher power output. It has been characterized from electromechanical, structural, and morphological aspects. The most successful self‐standing PENG fabric obtained (at 5% ZnO loading) doubled the energy output of the fabric made from pure PVDF nanofiber yarn and provided a peak total power of 81 μW and a power density of 30 μW/cm2. The present results open up the field for the development of PVDF/ZnO‐based nanomats and their use in sensors and actuators in the healthcare and engineering industries.

Multiphasic bone-ligament-bone integrated scaffold enhances ligamentization and graft-bone integration after anterior cruciate ligament reconstruction

The escalating prevalence of anterior cruciate ligament (ACL) injuries in sports necessitates innovative strategies for ACL reconstruction. In this study, we propose a multiphasic bone-ligament-bone (BLB) integrated scaffold as a potential solution. The BLB scaffold comprised two polylactic acid (PLA)/deferoxamine (DFO)@mesoporous hydroxyapatite (MHA) thermally induced phase separation (TIPS) scaffolds bridged by silk fibroin (SF)/connective tissue growth factor (CTGF)@Poly(l-lactide-co-ε-caprolactone) (PLCL) nanofiber yarn braided scaffold. This combination mimics the native architecture of the ACL tissue. The mechanical properties of the BLB scaffolds were determined to be compatible with the human ACL. In vitro experiments demonstrated that CTGF induced the expression of ligament-related genes, while TIPS scaffolds loaded with MHA and DFO enhanced the osteogenic-related gene expression of bone marrow stem cells (BMSCs) and promoted the migration and tubular formation of human umbilical vein endothelial cells (HUVECs). In rabbit models, the BLB scaffold efficiently facilitated ligamentization and graft-bone integration processes by providing bioactive substances. The double delivery of DFO and calcium ions by the BLB scaffold synergistically promoted bone regeneration, while CTGF improved collagen formation and ligament healing. Collectively, the findings indicate that the BLB scaffold exhibits substantial promise for ACL reconstruction. Additional investigation and advancement of this scaffold may yield enhanced results in the management of ACL injuries.

MXene nanosheets woven in polyacrylonitrile nanofiber yarns aligned spider web as a highly efficient sorbent for in-tube solid phase microextraction of beta-blockers from biofluids

The use of electrospinning has received much attention in the production of nanofiber webs due to its advantages such as flexibility and simplicity. The direct electrospinning of nanofibers in an aligned or twisted form and the production of nanofiber yarns can turn nanofibers into woven fabrics, which leads to an increase in the diversity of nanofiber applications and improves their end-use possibilities. In this work, a victorious nanofiber yarn spinning system was used with the help of a rotating funnel. Yarn formation was studied using a composited polyacrylonitrile (PAN)/MXene polymer solution ejected from two oppositely charged nozzles. Finaly their application for packed-in-tube solid-phase microextraction of β-blocker drugs from biofluids was demonstrated. The separation and quantification of analytes were performed by HPLC-UV instrument. The 3D-yarn PAN/MXene sorbent exhibited high flexibility, porosity, sorbent loading, mechanical stability, and a long lifetime. The characterization of the final nanofiber was carried out utilizing Fourier-transform infrared spectroscopy, field emission scanning electron microscope, energy-dispersive X-ray mapping, transmission electron microscope and X-ray diffraction analysis. Various parameters that affect the extraction efficiency, such as extraction time, pH, ionic strength and flow rate of sample solution, and type, volume and flow rate of eluent, were investigated and optimized. Under optimized conditions, the limits of detection were obtained in the range of 1.5–3.0 μg L−1. This method demonstrated appropriate linearity for β-blockers in the range of 5.0–1000.0 μg L−1, with coefficients of determination greater than 0.990. The inter- and intra-assay precisions (RSDs, for n = 3) are in the range of 2.5–3.5%, and 4.5–5.2%, respectively. Finally, the validated method was put in an application for the analysis of atenolol, propranolol and betaxolol in human urine and saliva samples at different hours and acceptable relative recoveries were obtained in the range of 89.5% to 110.4%.