Substantial challenges remain in developing fiber devices to achieve uniform and customizable photochromic lighting effects using lightweight hardware. A recent publication in Light Science & Application, spearheaded by Prof. Yan-Qing Lu and Prof. Guangming Tao presents a methodical approach to surmount the limitations in photochromic fibers. They integrated controllable photochromic fibers into various wearable devices, providing a promising path for future exploration and advancement in the field of human–machine interaction.
Smart wearables equipped with integrated flexible actuators possess the ability to autonomously respond and adapt to changes in the environment. Fibrous textiles have been recognised as promising platforms for integrating flexible actuators and wearables owing to their superior body compliance, lightweight nature, and programmable architectures. Various studies related to textile actuators in smart wearables have been recently reported. However, the review focusing on the advanced design of these textile actuator technologies for smart wearables is lacking. Herein, a timely and thorough review of the progress achieved in this field over the past five years is presented. This review focuses on the advanced design concepts for textile actuators in smart wearables, covering functional materials, innovative architecture configurations, external stimuli, and their applications in smart wearables. The primary aspects focus on actuating materials, formation techniques of textile architecture, actuating behaviour and performance metrics of textile actuators, various applications in smart wearables, and the design challenges for next-generation smart wearables. Ultimately, conclusive perspectives are highlighted.
One-dimensional (1D) mesoporous nanofibers (NFs) have recently attracted tremendous interest in different fields, in virtue of their mesoporous structure and 1D geometry. However, conventional electrospinning, as a versatile approach for producing 1D nanostructures, can only fabricate solid NFs without pores or with a microporous structure. In this review, we focus on the extensions of the electrospinning technique to create 1D mesoporous fibrous structures, which can be categorized into: (i) foaming-assisted, (ii) phase separation-induced, (iii) soft-templated, and (iv) monomicelle-directed approaches. Special focus is on the synthesis strategies of 1D mesoporous NFs, and their underlying mechanisms, with looking into the control over pore sizes, pore structures, and functionalities. Moreover, the structure-related performances of mesoporous NFs in photocatalysis, sensing, and energy-related fields are discussed. Finally, the potential challenges for the future development of 1D mesoporous fibers are examined from the viewpoint of their synthetic strategies and applications.
Acute liver failure (ALF) has a mortality rate of more than 40%. Currently, orthotopic liver transplantation is the sole clinical treatment for ALF, but its wide usage is severely limited due to donor shortage and immunological rejection. An emerging and promising technology for ALF treatment is liver tissue engineering (LTE), wherein porous scaffolds serve as a crucial component. Nanofiber scaffolds, which mimic the inherent structures of fibrous extracellular matrix well, provide an ideal environment for cell growth and tissue regeneration. Recently, several functional nanofiber scaffolds for LTE have been developed, which show impressive results in regulating cell function and repairing liver injury when combined with appropriate seeding cells and/or growth factors. This review firstly introduces the etiologies and treatment indicators of ALF. Subsequently, typical fabrication technologies of nanofiber scaffolds and their related applications for function regulation of liver-related cells and treatment of ALF are comprehensively summarized. Particular emphasis is placed on the strategies involving an appropriate combination of suitable seeding cells and growth factors. Finally, the current challenges and the future research and development prospects of nanofiber scaffold-based LTE are discussed. This review will serve as a valuable reference for designing and modifying novel nanofiber scaffolds, further promoting their potential application in LTE and other biomedical fields.
In this study, we developed a hollow aerogel fiber out of reduced graphene oxide (rGO), with a hierarchically ordered microstructure through a three-dimensional coaxial printing methodology, that enabled a physicochemically cooperative construction process at multiscale. The rGO hollow aerogel fiber was modified by depositing polycaprolactone (PCL) and melatonin (Mel). Attributable to its elaborately designed hierarchical structure and arched alignment of two-dimensional micro-sheets, the rGO/PCL/Mel hybrid aerogel bio-fiber demonstrated remarkable structural robustness in maintaining ordered pathways and high porosity (98.5% ± 0.24%), which facilitated nerve growth in a complex survival environment in vivo. Furthermore, the excellent combination of properties such as electrical conductivity, biocompatibility, and mechanical properties (elastic modulus: 7.06 ± 0.81 MPa to 26.58 ± 4.99 MPa) led to highly efficient regeneration of well-ordered PN tissue. Systematic evaluations of nerve regeneration and muscle function recovery in a Sprague–Dawley rat model with a long nerve defect (15 mm) validated the virtually identical performance of the rGO/PCL/Mel fiber compared to autogenous nerve graft. This study suggests a promising approach to the clinical repair of long PN defects through the combined regulation of rational multiscale structure design and indispensable chemical modification of rGO aerogel-based functional nerve regeneration fibers.
Quasi-solid-state electrolytes that possess high ionic conductivity, excellent interface stability, and low interfacial resistance, are required for practical solid-state batteries. Herein, a heterogeneous quasi-solid-state hybrid electrolyte (QSHE) with a robust lithium-ion transport layer composed of Li1+xAl xTi2−x(PO4)3 (LATP) nanoparticles (NPs) at the anode/electrolyte interface was fabricated using electrospun nanofibers as a skeleton via a facile in situ polymerization approach. The QSHE exhibits a high ionic conductivity (0.98 mS cm−1), a wide electrochemical window (4.76 V vs. Li/Li+), and favorable compatibility with lithium metal (maintaining stability over 2000 h in a symmetrical cell) at room temperature. When coupled with a Li|LiFePO4 battery, the QSHE enables the battery to retain 95.4% of its capacity after 300 cycles at 2 C. Moreover, the atomic force microscopy verifies the high Young’s modulus of the LATP-dominated bottom layer, while numerical simulation validates the effective distribution of lithium ions at the interface facilitated by LATP NPs, hence contributing to dendrite-free lithium plating/stripping morphology. This straightforward strategy could pave the way for the development of high-performance and interfacially stable lithium metal batteries.
With the rapid development of 5G communication and artificial intelligence (AI) technology, electromagnetic radiation pollution is emerging as a serious issue. Achieving both uniform dispersion and controllable loading of absorbers and obtaining functional wearable absorbers with high electromagnetic response are still considered great challenges. In this work, a flexible fiber-based absorber (VFT2h/MF/PPy) with a rich interfacial polarization relaxation was obtained by integrating heterostructures and performing nanostructure design and introducing π-conjugated polymer components. Electrons migrated and redistributed between nanoparticles and nitrogen-carbon lattices with different electrostatic states. The formed heterogeneous interface promoted the electromagnetic attenuation response in the high-frequency region. More specifically, the effective absorption frequency bandwidth was up to 5.6 GHz (corresponds to the Ku-band with a matching thickness range up to 2.55–4.85 mm). Impressively, the abundant modification sites on the fiber surface adjusted the content and dispersion of the magnetic nanoparticles and enhanced the vector superposition effect generated by the structural distribution of the magnetic/electric fields. The introduction of dielectric components improved the interfacial polarization strength of the heterojunction surface and the synergistic effect of the dipolar polarization. The high-efficiency electromagnetic attenuation performance was attributed to multiple loss mechanisms. Our work provides a reference path for the microscopic regulation of the high-efficiency electromagnetic response mechanism of fiber-based flexible absorbing materials.
The green preparation of highly dispersed carbon nanotube (CNT) conductive inks remains a critical challenge in the field of flexible electronics. Herein, a waterborne CNT dispersion approach mediated by carboxylated cellulose nanofibers (C-CNFs) was proposed. CNFs, special biomass materials with excellent nanostructures and abundant active surface groups, are used as green dispersants. During the dispersion process, benefiting from chemical charge and dimensional matching, C-CNF/CNT wicking-driven stable composite structures (CCNTs) were co-assembled via hydrogen bonding, electrostatic stabilization and π–π stacking between the interfaces, generating controlled orientational structures and promoting stable dispersion and conductivity of CNTs, which were demonstrated via molecular dynamics simulations combined with a variety of physicochemical characterization methods. The dispersion concentration of CNTs in a CCNT slurry can reach 80 wt%, and the obtained CCNT slurry has a low zeta potential (less than − 60 mV) and good stability. Due to the film-forming properties of CNFs and in-plane oriented self-assembly of CCNT, the composite self-supporting films were fabricated with high electrical conductivity (67 S cm−1) and mechanical performance (tensile strength of 153 MPa). In addition, the resulting biobased CCNT ink is compatible with a variety of printing processes and adaptable to various substrates. Moreover, this ink can be used to construct multifunctional advanced sensors with electrochemical, electrothermal, and deformation/piezoresistive responses, which demonstrate excellent performance in monitoring human health.
Sulfurized polyacrylonitrile (SPAN) has emerged as an excellent cathode material for lithium–sulfur batteries (LiSBs), and it addresses the shuttle effect through a solid‒solid reaction. However, the actual sulfur loadings in SPAN often remain below 40 wt%. Due to the susceptibility of polysulfides-to-nucleophilic reactions with electrolytes, achieving physical encapsulation of elemental sulfur is a challenging task. In this study, a free-standing cathode material with a high sulfur/selenium (S/Se) loading of 55 wt% was fabricated by introducing SeS x into the unique lotus root-like pores of porous SeS xPAN nanofiber membranes by electrospinning and a two-step heat treatment. Insoluble compounds were formed due to nucleophilic interactions between lithium polyselenosulfides (LiSeS x) and the electrolyte, which potently blocked the existing lotus root-like pores and facilitated the creation of a thin cathode–electrolyte interphase on the fiber surface. This dual functionality of LiSeS x safeguarded the active material embedded within the porous structure. The SeS15PAN cathode exhibited remarkable cycling stability with almost no degradation after 200 cycles at 0.2 C, along with a high discharge capacity of 580 mAh/g. This approach presents a solution for addressing the insufficient sulfur content in SPAN.
The insufficient comprehensive mechanical properties and inadequate flexibility of wearable sensors limit their body-protection capability, durability, and comfort. There are challenges in using flexible wearable devices for high-performance practical applications, especially on large scales. Here, an ultrahigh-strength ultra-high-molecular-weight polyethylene braided smart yarn (UBSY) has been designed and mass produced. It is based on triboelectric nanogenerators and prepared by combining commercial ultra-high-molecular-weight polyethylene yarn and conductive yarn with a cored biaxial braided structure. Structural parameters, including the ultra-high-molecular-weight polyethylene yarn diameter, twist, and braiding pitch, are optimized to balance the mechanical properties and electrical outputs. The prepared UBSYs are characterized based on a range of reliable properties, including ultrahigh tensile strength (194.83 N), excellent abrasive resistance (up to 306 abrasive cycles), great hydrophobicity (water contact angle of 115.49°), acid and alkali splash resistance, and decent triboelectric outputs (1.5 V, 3.0 nA, and 0.5 nC). An intelligent weft-knitted textile wearable sensor is fabricated with UBSY using a matured flat-knitting technique, which provides excellent mechanical strength, physical protection and comfort. Furthermore, a pair of smart elbow guards have been demonstrated to highlight UBSY-based wearable sensors’ potential in outdoor sports management. In addition, equipped with a satisfactory body protective capacity against various risks and matured preparation technologies, the UBSY-based wearable sensor provides a practical solution for large-scale applications of high-performance motion sensing in complex environments.
The demand for wearable electronics is still growing, and the rapid development of new electrochemical materials and manufacturing processes allows for innovative approaches to power these devices. Here, three-dimensional (3D) self-supported reduced graphene oxide/poly(3,4-ethylenedioxythiophene) (rGO/PEDOT) hybrid fiber fabrics are systematically designed and constructed via phase inversion-based microfluidic-fiber-spinning assembly (MFSA) method, followed by concentrated sulfuric acid treatment and chemical reduction. The rGO/PEDOT fiber fabrics demonstrate favorable flexibility, interconnected hierarchical network, large specific surface area, high charge storage capacity, and high electrical conductivity. In addition, the all-solid-state supercapacitor made of these rGO/PEDOT fiber fabrics proves large specific capacitance (1028.2 mF cm−2), ultrahigh energy density (22.7 μWh cm−2), long-term cycling stability, and excellent flexibility (capacitance retention remains at 84%, after 5000 cycles of continuous deformation at 180o bending angles). Further considering those remarkable electrochemical properties, a wearable self-powered device with a sandwich-shaped supercapacitor (SC) is designed to impressively light up LEDs and power mini game console, suggesting its practical applications in flexible and portable smart electronics.
Lithium–sulfur (Li–S) batteries can potentially outperform state-of-the-art lithium-ion batteries, but their further development is hindered by challenges, such as poor electrical conductivity of sulfur and lithium sulfide, shuttle phenomena of lithium polysulfides, and uneven distribution of solid reaction products. Herein, free-standing carbon nanofibers embedded with oxygen-deficient titanium dioxide nanoparticles (TiO2-x/CNFs) has been fabricated by a facile electrospinning method, which can support active electrode materials without the need for conductive carbon and binders. By carefully controlling the calcination temperature, a mixed phase of rutile and anatase was achieved in the TiO2-x nanoparticles. The hybridization of anatase/rutile TiO2-x and the oxygen vacancy in TiO2-x play a crucial role in enhancing the conversion kinetics of lithium polysulfides (LiPSs), mitigating the shuttle effect of LiPSs, and enhancing the overall efficiency of the Li–S battery system. Additionally, the free-standing TiO2-x/CNFs facilitate uniform deposition of reaction products during cycling, as confirmed by synchrotron X-ray imaging. As a result of these advantageous features, the TiO2-x/CNFs-based cathode demonstrates an initial specific discharge capacity of 787.4 mAh g−1 at 0.5 C in the Li–S coin cells, and a final specific discharge capacity of 584.0 mAh g−1 after 300 cycles. Furthermore, soft-packaged Li–S pouch cells were constructed using the TiO2-x/CNFs-based cathode, exhibiting excellent mechanical properties at different bending states. This study presents an innovative approach to developing free-standing sulfur host materials that are well suited for flexible Li–S batteries as well as for various other energy applications.
High-performance and reliable wearable devices for healthcare are in high demand for the health monitoring of infants, ensuring that life-threatening events can be addressed promptly. Herein, the continuous monitoring of infant respiration for preventing sudden infant death syndrome (SIDS) is proposed using high-performance flexible piezoresistive sensors (FPS). The thorny challenges associated with FPS, including the signal drift and poor repeatability, are progressively improved via the employment of high-Tg matrix, the strengthening of in situ graft-on conducting polyaniline layer by β-cyclodextrin (β-CD), and the nanostructure interlocking between the piezoresistive layer and electrodes. The sensor presents high linear sensitivity (30.7 kPa−1), outstanding recoverability (low hysteresis up to 1.98% FS), static stability (4.00% signal drift after 24 h at 2.4 kPa) and dynamic stability (1.92% decay of signal intensity after 50,000 cycles). A wireless infant respiration monitoring system is developed. Respiration patterns and the real-time respiration rate are displayed on the phone. Notifications are implemented when abnormal status such as bradypnea and tachypnea is detected.
Real-time monitoring of pressure and temperature in wheelchair patients is an effective method for preventing and rehabilitating pressure injuries. Nevertheless, few rehabilitation devices capable of monitoring temperature and pressure have been reported. Herein, we propose a fully textile-based scalable and designable dual-mode rehabilitation cushion for real-time monitoring of pressure and temperature. The different signal output modes (resistive and capacitive signals) enable noninterference between pressure and temperature. The cushion exhibits a wide pressure monitoring range of 2–160 kPa, a high sensitivity of 8.8399 kPa−1, and a repeatable stability exceeding 10,000 cycles. In addition, the cushion demonstrates excellent temperature responsiveness with a linearity of 0.995 and a TCR of 0.019 s°C−1. Furthermore, an intelligent monitoring system integrated with machine learning has been developed to realize large-range multipoint sensing and data visualization. The system can accurately recognize different sitting postures with an accuracy of 99.65%. Human application evaluations have demonstrated the feasibility of this cushion for preventing pressure injuries, which can stimulate further research on pressure injury prevention and rehabilitation in the future.
High-performance multifunctional filtration membranes are highly required in treating practically complex oily wastewater systems, but still a challenge unsolved. Herein, we propose a facile route to address these challenges simultaneously by simply constructing electrospun pre-oxidized polyacrylonitrile nanofibrous membrane (p-PAN NM). Given the pre-oxidation process, the p-PAN NM displays not only robust anti-corrosive tolerance against diverse corrosive media, but also superhydrophilicity/underwater superoleophobicity. Additionally, ~ 99% separation efficiency, ~ 100% oil-fouling recovery, and ultra-long service life (up to 265 h) have been realized in separating large-scale surfactant stabilized soybean/crude oil-in-water emulsions. Furthermore, strong anti-corrosive performance against various corrosive media (e.g., 1 M HCl, 1 M NaOH, or 10 wt% NaCl) has been achieved as well. Spin-unrestricted density functional theory (DFT) computations implemented in the Dmol3 modulus has been conducted to understand the robust fouling recovery and the variation of surficial wettability after pre-oxidation. These outstanding filtration functions make our NM hold great potential in separating viscous oil/water emulsions under harsh conditions.
Fully inorganic metal halide perovskites (MHPs) demonstrate enhanced stability over their organic–inorganic counterparts, however, their integrations into flexible or textile-based substrates remain a significant challenge, due to their inherent rigidity and the necessity of high-temperature annealing. Herein, we propose a one-step and near-room-temperature electrospinning process to fabricate flexible CsPbI2Br nanofibers that can be directly deposited on the yarns. With the in-situ CsPbI2Br crystallization during electrospinning, annealing-free and photoelectroactive γ-CsPbI2Br can be achieved. Polyvinyl acetate (PVAc) serves as the carrier polymer to offer the flexibility and facilitate the chemical interaction with CsPbI2Br, thereby mitigating moisture and oxygen-induced degradations. CsPbI2Br-PVAc nanofibers obtained under the optimal electrospinning condition: high-electrospinning voltage (25 kV) and low-solution supply rate (0.02 mm/min), show more uniform morphology, increased stability, and extended photoluminescence decay time. These nanofibers enable the construction of photo-sensing yarn devices, capable of generating a photovoltage of around 180 mV and current density of 17 mA/cm2 upon illumination by a 532 nm pulsed laser, while maintaining a remarkable ambient stability of 16 days. Given their laser-energy-dependent voltage output, these yarns hold significant potential for developing high-intensity light-detecting textiles for various applications.
The low ionic conductivities, poor high-voltage stabilities, and lithium dendrite formation of polymer solid electrolytes preclude their use in all-solid-state lithium metal batteries (ASSLMBs). This work provides a simple and scalable technique for constructing fast ion conductor nanofibers (FICNFs) and poly-m-phenyleneisophthalamide (PMIA) nanofibers synergistically enhanced polyethylene oxide (PEO)-based composite solid electrolytes (CSEs) for ASSLMBs. The FICNFs, which were mainly composed of high loadings of ZrO2 or Li6.4La3Zr1.4Ta0.6O12 nanoparticles, had a percolated ceramic phase inside the nanofibers, while the exposed nanoparticles formed continuous organic–inorganic interfaces with the PEO matrix to enable Li+ transport. The interfacial transport rate between ZrO2 and PEO was calculated as 4.78 × 10–5 cm2 s−1 with ab initio molecular dynamics (AIMD) simulations. Besides, the PMIA nanofibers provided strong skeletal support for the CSEs, ensuring excellent mechanical strength and safety for thin CSEs even at high temperatures. More importantly, the amide groups in PMIA provided abundant hydrogen bonds with TFSI−, which lowered the lowest unoccupied molecular orbital (LUMO) level of lithium salts, thus promoting the generation of lithium fluoride-rich solid electrolyte interphase. Consequently, the modified CSEs exhibited satisfactory ionic conductivities (5.38 × 10–4 S cm−1 at 50 °C) and notable Li dendrite suppression (> 1500 h at 0.3 mAh cm−2). The assembled LiFePO4||Li full cells display ultra-long cycles (> 2000 cycles) at 50 °C and 40 °C. More strikingly, the LiNi0.8Mn0.1Co0.1O2 (NMC811)||Li cell also can stably run for 500 cycles, and the LiFePO4||Li flexible pouch cells also cycled normally, demonstrating tremendous potential for practical application.
The systematic integration of color-changing and shape-morphing abilities into entirely soft devices is a compelling strategy for creating adaptive camouflage, electronic skin, and wearable healthcare devices. In this study, we developed soft actuators capable of color change and programmable shape morphing using elastic fibers with a liquid metal core. Once the hollow elastic fiber with the thermochromic pigment was fabricated, liquid metal (gallium) was injected into the core of the fiber. Gallium has a relatively low melting point (29.8 °C); thus, fluidity and metallic conductivity are preserved while strained. The fiber can change color by Joule heating upon applying a current through the liquid metal core and can also be actuated by the Lorentz force caused by the interaction between the external magnetic field and the magnetic field generated around the liquid metal core when a current is applied. Based on this underlying principle, we demonstrated unique geometrical actuations, including flower-like blooming, winging butterflies, and the locomotion of coil-shaped fibers. The color-changing and shape-morphing elastic fiber actuators presented in this study can be utilized in artificial skin, soft robotics, and actuators.
Existing personal thermal regulating fabrics fall short of meeting the demands for sustainable and protective outdoor temperature management. Here, a versatile and comfortable Janus fabric has been developed by embedding boron nitride nanosheets within a porous polyurethane matrix (BNNS@TPU) and introducing Ti3C2Tx MXene into another layer of TPU pores (MXene/TPU). The well-distributed BNNS in porous TPU matrix enhances refractive index difference, increases porosity and optimizes pore size distribution, resulting in an excellent solar reflectivity (R = 94.22%), while the distinct distribution of MXene in porous TPU effectively improves solar absorptivity (α = 93.57%) and enhances the conduction loss of electromagnetic waves due to multiple scattering and reflection effects. With a simple flip, Janus fabric can switch between sub-ambient cooling of ~ 7.2 °C and super-ambient heating of ~ 46.0 °C to adapt to changing weather and seasonal conditions. The fabric achieves an electromagnetic interference shielding efficiency of 36 dB, protecting the human body from electromagnetic radiation, attributed to the hierarchical distribution of highly conductive MXene. Furthermore, Janus fabric offers excellent comfort, abrasion resistance, washability, and flame retardancy for practical wear. This study presents an effective strategy for developing personal thermal regulating fabrics with adaptability to environmental changes and resistance to electromagnetic radiation.
Flexible yarn sensors designed for integration into textiles have the potential to revolutionize wearable technology by continuously monitoring biomechanical strain. However, existing yarn-shaped sensors rely on capacitance as a strain-dependent electrical signal and often face limitations in achieving high sensitivity, especially across a broad strain range. Here, we propose a waterproof all-in-one capacitive yarn sensor (ACYS) that is tailored to monitor a wide range of biophysical strains. Owing to the coaxial helical electrode and the ionic liquid-doped dielectric layer, the ACYS demonstrates remarkable stretchability, ultrahigh capacitance variation, and an outstanding gauge factor of 6.46 at 140% strain. With exceptional mechanical durability based on enduring 3300 stretching cycles and favorable resistance to sweat erosion, this 1D structure can be seamlessly integrated into textiles, making it ideal for use in wearable electronics. Demonstrating its application versatility, the ACYS accurately measures biomechanical strain in joint movements, facial expressions, and physiological assessments, making it a promising advancement in wearable technology.