Flexible intelligent sensing is a burgeoning field of study that covers various disciplines, including but not restricted to chemistry, physics, electronics and biology. However, the widespread use of flexible sensors remains challenging because of certain constraints, such as limited stretchability, poor biocompatibility, low responsivity, and the complexity of multifunctional integration. Conductive hydrogels with remarkable material properties are presently in the spotlight of flexible sensing. In the pursuit of high-performance and “green” conductive hydrogel-based sensors, cellulose is a promising candidate owing to its renewability, low cost, appealing mechanical properties, easy modification and other functional characteristics. Herein, cutting-edge progress in the fabrication of conductive cellulose hydrogels (CCHs) using cellulose and cellulose derivatives in terms of structural features, preparation approaches, functional properties, applications, and prospects for sensors is comprehensively summarized. The correlation between CCHs performances, reinforcement strategies and sensor properties is highlighted to gain insight into the process of developing smart sensors by utilizing CCHs. Besides, the state-of-the-art advances of CCHs toward emerging wearable sensors, including strain/pressure sensors, temperature sensors, humidity sensors, and biosensors, are systematically discussed. Finally, potential challenges and future outlooks of such attractive CCH-based flexible sensors are presented, providing valuable information for the development of next-generation cellulose-based electronic devices.
Air pollutants, which are composed of diverse components such as particulate matter (PM), volatile organic compounds (VOCs), nitrogen oxides (NO x), sulfur dioxide (SO2), and pathogenic microorganisms, have adverse effects on both the ecosystem and human health. While existing air purification technologies can effectively eliminate these pollutants through multiple processes targeting specific components, they often entail high energy consumption, maintenance costs, and complexity. Recent developments in air purification technology based on multifunctional nanofibrous membranes present a promising single-step solution for the effective removal of diverse air pollutants. Through synergistic integration with functional materials, other functional materials, such as those with catalytic, adsorption, and antimicrobial properties, can be incorporated into nanofibrous membranes. In this review, the design concepts and fabrication strategies of multifunctional nanofibrous membranes to facilitate the integrated removal of multiple air pollutants are explored. Additionally, nanofibrous membrane preparation methods, PM removal mechanisms, and performance metrics are introduced. Next, methods for removing various air pollutants are outlined, and different air purification materials are reviewed. Finally, the design approaches and the state-of-the-art of multifunctional nanofibrous membranes for integrated air purification are highlighted.
Cellulose has sparked considerable interest in the advancement of biodegradable functional materials owing to its abundant natural sources and exceptional biocompatibility. This review offers a comprehensive review of the latest research and development concerning cellulose-based films, with a specific emphasis on their classification, properties, and applications. Specifically, this review classifies cellulose according to the various morphologies of cellulose (e.g., nanocrystals, nanospheres, and hollow ring cellulose) and cellulose derivatives (e.g., methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and cellulose acetate). The subsequent section presents an analysis of cellulose-based films with improved mechanical properties, antibacterial characteristics, gas regulation, and hydrophobicity. A detailed discussion of the mechanisms that underlie these properties is provided. Additionally, representative applications of cellulosic composites, such as food packaging, medical supplies, and electronic devices, are summarized. Finally, the challenges faced by cellulosic materials are outlined, and a novel and feasible prospect is proposed to accelerate the future development of this material.
We developed kinetic energy-harvestable and kinetic movement-detectable piezoelectric nanogenerators (PENGs) consisting of piezoelectric nanofiber (NF) mats and metal-electroplated microfiber (MF) electrodes using electrospinning and electroplating methods. Percolative non-woven structure and high flexibility of the NF mats and MF electrodes allowed us to achieve highly transparent and flexible piezocomposites. A viscoelastic solution, mixed with P(VDF-TrFE) and BaTiO3, was electrospun into piezoelectric NFs with a piezoelectric coefficient d 33 of 21.2 pC/N. In addition, the combination of electrospinning and electroplating techniques enabled the fabrication of Ni-plated MF-based transparent conductive electrodes (TCEs), contributing to the high transparency of the resulting piezocomposite. The energy-harvesting efficiencies of the BaTiO3-embedded NF-based PENGs with transmittances of 86% and 80% were 200 and 240 V/MPa, respectively, marking the highest values in their class. Moreover, the output voltage driven by the coupling effect of piezoelectricity and triboelectricity during finger tapping was 25.7 V. These highly efficient energy-harvesting performances, along with the transparent and flexible features of the PENGs, hold great promise for body-attachable energy-harvesting and sensing devices, as demonstrated in this study.
Self-healable electronics with self-recoverable mechanical properties show a lot of potential in improving the reliability and durability of wearable electronic devices, but it is still challenging. Herein, a self-healing core-sheath thermoelectric (TE) fiber-based temperature sensor was continuously fabricated by coaxial wet-spinning strategy, whose core layer and sheath layer are, respectively, pure Ti3C2T x MXene and self-healing silk sericin (SS)/oxide sodium alginate (OSA) composite. The prepared SS/OSA@MXene core-sheath TE fiber exhibits accurate temperature-sensing at 200–400 °C based on a linear relationship between TE voltage and temperature difference. The core-sheath TE fiber that can be integrated into firefighting clothing and timely alert firefighters to evacuate from the fire before the protective clothing becomes damaged. When exposed to flames, SS/OSA@MXene can rapidly trigger a high-temperature warning voltage of 3.36 mV within 1.17 s and exhibit reversible high-temperature alarm performance. In addition, the fractured SS/OSA@MXene can restore up to 89.12% of its original strain limit at room temperature because of the robust yet reversible dynamic covalent bonds between SS and OSA. In this study, an ingenious strategy for developing a durable and wearable TE fiber-based self-powered temperature sensor was proposed. This strategy has promising application prospects in real-time temperature detection of firefighting clothing to ensure the safety of firefighters operating on a fire scene.
Respiration is a critical physiological process of the body and plays an essential role in maintaining human health. Wearable piezoelectric nanofiber-based respiratory monitoring has attracted much attention due to its self-power, high linearity, noninvasiveness, and convenience. However, the limited sensitivity of conventional piezoelectric nanofibers makes it difficult to meet medical and daily respiratory monitoring requirements due to their low electromechanical conversion efficiency. Here, we present a universally applicable, highly sensitive piezoelectric nanofiber characterized by a coaxial composite structure of polyvinylidene fluoride (PVDF) and carbon nanotube (CNT), which is denoted as PS-CC. Based on elucidating the enhancement mechanism from the percolation effect, PS-CC exhibits excellent sensing performance with a high sensitivity of 3.7 V/N and a fast response time of 20 ms for electromechanical conversion. As a proof-of-concept, the nanofiber membrane is seamlessly integrated into a facial mask, facilitating accurate recognition of respiratory states. With the assistance of a one-dimensional convolutional neural network (CNN), a PS-CC-based smart mask can recognize respiratory tracts and multiple breathing patterns with a classification accuracy of up to 97.8%. Notably, this work provides an effective strategy for monitoring respiratory diseases and offers widespread utility for daily health monitoring and clinical applications.
Personalized wound dressings with on-site deposition, exudate suction, and reproducible sterilization are urged for treating diabetic wounds. Herein, we have developed nanofiber membranes incorporating a V-shaped photosensitizer (VPS), a donor-acceptor-donor type organic semiconductor with indacenodithienothiophene (IDTT) as the electron-donor and triphenyleno[1,2-c:7,8-c′]bis([1,2,5] -thiadiazole) (TPTz) as the electron-acceptor, for multifunctional wound dressing. The VPS-incorporated nanofiber membranes are in situ deposited on rough wounds by using a handheld electrospinning device, which offers full coverage and better affinity than gauze to stop bleeding and suck exudate rapidly. They are breathable, waterproof, and have bacteria repelling capacity due to their hydrophobicity and negative charges. Upon light irradiation, the VPS in nanofibers undergoes low aggregation-caused quenching and retains high fluorescence and reproducible photodynamic sterilization towards both Gram-positive and Gram-negative bacteria. The nanofiber dressing also promotes cell adhesion and proliferation and exhibits high security in blood biochemistry and hematology. With the above merits, the nanofiber membranes greatly reduce the expression of tumor necrosis factor α and interleukin 6 in serum and wound tissues, expediting the wound healing process. These wound dressings combine the benefits of in situ electrospinning, fiber membrane, and VPS, and will provide strategies for emergency medical operations.
Nociceptive-selective analgesia is often preferred over traditional methods, providing effective pain relief with minimum systemic side effects.The quaternary lidocaine derivative QX-314, is a promising local anesthetic for achieving selective analgesia. However, due to its inability to penetrate the cell membrane, its efficacy is limited to intracellular administration. In this study, we aimed to develop an injectable electrospun fiber-hydrogel composite comprising QX-314-loaded poly(ε-caprolactone) electrospun fiber and capsaicin (Cap)-loaded F127 hydrogel (Fiber-QX314/Gel-Cap composite) for long-term and nociceptive-selective analgesia. The sequential and sustained release mechanism of Cap and QX-314 helped remarkably extend the sensory blockade duration up to 44.0 h, and prevent motor blockade. Specifically, our findings indicated that QX-314 can traverse the cell membrane through the transient receptor potential vanilloid 1 channel activated by Cap, thus targeting the intracellular Na+ channel receptor to achieve selective analgesia. Moreover, the composite effectively alleviated incision pain by suppressing c-Fos expression in the dorsal root ganglion and reducing the activation of glial cells in the dorsal horn of the spinal cord. Consequently, the Fiber-QX314/Gel-Cap composite, designed for exceptional biosafety and sustained selective analgesia, holds great promise as a non-opioid analgesic.
It is a worldwide challenge to achieve an efficient cleaning of heavy oil at ambient temperature. Conventional cleanup methods for high-viscosity oil spills exhibit low absorption efficiency and have severe practical operating limits. Herein, inspired by the passive transport process in the Salvinia cucullata, a solar-heated and joule-heated textile-based absorber using the scalable electrostatic flocking technique. Benefiting from the efficient photothermal and electrothermal conversion effects, the textile-based absorber, with oleophilic and aligned channels, facilitates thermal conduction and hence enhances heavy oil absorption. The absorber is highly efficient for organic solvents (chloroform and dichloromethane) and low-viscosity oils (silicone oil, gasoline, and diesel oil). The surface temperature of the textile absorber rises rapidly to 92 °C (114 °C) in 120 s (240 s) under one sun irradiation (or 5 V voltage), resulting in a sharp drop in the viscosity of the heavy oil and then achieving an ultrahigh absorption rate (2647 kg h−1 m−2) and fast equilibrium time (25 s). Rapid absorption rate significantly reduces spill cleanup time and spill spreading area, hence alleviating the environmental harm caused by oil spills as much as possible. The proposed solar-heated and joule-heated textile-based absorbers with aligned channels show great potential for efficient heavy oil absorption.
Medical hemostatic gauze is one of the most common agents for bleeding management used in pre-hospital care and clinical treatment. An ideal hemostat requires the features including fast coagulation ability, high biocompatibility and low cost, which is difficult to be achieved simultaneously. Herein, we reported a chemical immobilization method to uniformly anchor the zeolitic imidazolate framework (ZIF-8) nanoparticles on polyvinyl alcohol (PVA) membrane, which dramatically accelerated the in vivo conversion process of prothrombin to thrombin, achieving a short hemostasis time around 60 s with a low amount of blood loss of 23 mg. Later, the hemostatic mechanism was unveiled by two pathways involving the activation of platelets and the conversion of prothrombin, indicating that this ZIF-8-based membrane works in a similar way to natural platelet-based physiological processes. More importantly, the convenient manufacturing and excellent biocompatibility of ZIF-8-based membrane provide a practical candidate hemostat for clinical bleeding management.
The exploration of high-efficiency transition metal–nitrogen–carbon (M–N–C) catalysts is crucial for accelerating the kinetics of oxygen reduction/oxygen evolution reactions (ORR/OER). Fine-tuning the distribution of accessible metal sites and the correlated triphase interfaces within the M–N–C catalysts holds significant promise. In this study, we present an integrated electrocatalyst comprised of tip-enriched NiFe nanoalloys encapsulated within N-doped carbon nanotubes (NiFe@CNTs), synthesized using an in-situ wet-electrochemistry mediated approach. The well-defined NiFe@CNTs catalyst possesses a porous heterostructure, synergistic M–Nx–C active sites, and intimate micro interfaces, facilitating accelerated redox kinetics. This leads to exceptional OER/ORR activities with a low overall ΔE of 630 mV. Experimental results and density functional theory calculations unveil the predominant electronic interplay between the apical bimetallic sites and neighboring N-doped CNTs, thereby enhancing the binding of intermediates on NiFe@CNTs. Molecular dynamics simulations reveal that the local gas–liquid environment surrounding NiFe@CNTs favors the diffusion/adsorption of the OH−/O2 reactants. Consequently, NiFe@CNTs contribute to high-performance aqueous Zn–Air batteries (ZABs), exhibiting a high gravimetric energy density (936 Wh kgZn –1) and superb cycling stability (> 425 h) at 20 mA cm–2. Furthermore, solid-state ZABs based on NiFe@CNTs demonstrate impressive electrochemical performance (e.g., peak power density of 108 mW cm−2, specific energy of 1003 Wh kgZn –1) and prominent flexibility. This work illuminates a viable strategy for constructing metal site-specific, cobalt-free, and integrated M–N–C electrocatalysts for multifunctional catalysis and advanced/flexible energy storage applications.
Waterborne organic pollutants pose significant threats to ecosystems and the health of billions worldwide, presenting a pressing global challenge. Advanced oxidation processes (AOPs) offer promise for efficient wastewater treatment, yet the efficacy and the reliability of current environmental catalysts hinder their widespread adoption. This study developed an as-cast nanostructured glassy fiber capable of rapidly activating persulfate and achieved the degradation of diverse organic contaminants within 60 s using the as-prepared fiber. The material is relatively robust and can be reused about 40 times. The exceptional catalytic performance of the fibers stemmed from their low atomic coordination numbers, which facilitated the generation of numerous unsaturated active sites and accelerated radical production rates through a one-electron transfer mechanism. Additionally, the glassy-nanocrystalline heterogeneous interface, achieved through our proposed nanostructuralization approach, exhibited electron delocalization behavior. This enhanced persulfate adsorption and reduced the energy barrier for heterolytic cleavage of peroxy bonds. These findings present a novel avenue for the rational structural design of high-performance environmental catalysts for advanced water remediation.
A separation membrane with low or clean energy costs is urgently required for energy-saving and long-term service since electric energy generated from burning non-renewable resources will gradually cause a burden to the environment. At present, the conventional membrane being used in one mode is critical for a variety of scenarios in real life, which suffers from a trade-off effect, short service life, being difficult to recycle after damage. Herein, we report a trimode purification membrane composed of an eco-friendly polycaprolactone (PCL) substrate and functional graphene dioxide/polyaniline (GO/PANI) particles. Due to the photothermal transfer and photocatalytic properties of GO/PANI blend, the composite membrane can absorb 97.44% solar energy to handle natural seawater or mixed wastewater, which achieves a high evaporation rate of 1.47 kg m−2 h−1 in solar-driven evaporation mode. For the photocatalytic adsorption–degradation mode, 93.22% of organic dyes can be adsorbed and degraded after 12 h irradiation under 1 kW m−2. Moreover, electric-driven cross-flow filtration mode as a supplement also shows effective rejection over 99% for organic dyes with a high flux over 40 L m−2 h−1 bar−1. The combination of solar-driven evaporation, photocatalytic adsorption–degradation, and electric-driven cross-flow filtration demonstrates a prospective and sustainable strategy to generating clean water from sewages.
A trimode self-cleaning composite membrane of bio-degradable substrate PCL and functional particles GO/PANI were successfully fabricated, which can purify natural seawater or mixed wastewater stably in solar-driven evaporation mode, handle organic dyes by reduction–oxidation chemical transformation in photothermal adsorption–degradation mode, and be applied in cross-flow filtration mode driven by electric as a supplement for rainy, cloudy days, or at night.
Space exploration provides unparalleled opportunities for unraveling the mysteries of our origins and exploring planetary systems beyond Earth. Long-distance space missions require successful protection against significant radiation exposure, necessitating the development of effective radiation shielding materials. This study developed aromatic amide polymer (AAP) and boron nitride nanotube (BNNT) composite fibers using lyotropic liquid crystal (LLC) and industrially viable wet-spinning processes. The uniaxially oriented 1D composite fibers provide the necessary continuity and pliability to fabricate 2D macroscopic textiles with low density (1.80 g cm−3), mechanical modulus (18.16 GPa), and heat stability (up to 479 °C), while exhibiting the improved thermal neutron absorption cross-section with thermal neutron-shielding performance (0.73 mm−1). These composite textiles also show high thermal conductivity (7.88 W m−1 K−1) due to their densely packed and uniaxially oriented structures. These enhanced characteristics render the fibers a highly promising material for space applications, offering robust protection for both astronauts and electronics against the dual threats of radiation and heat.
Organ-on-a-chip stands as a pivotal platform for skeletal muscle research while constructing 3D skeletal muscle tissues that possess both macroscopic and microscopic structures remains a considerable challenge. This study draws inspiration from LEGO-like assembly, employing a modular approach to construct muscle tissue that integrates biomimetic macroscopic and microscopic structures. Modular LEGO-like hybrid nanofibrous scaffold bricks were fabricated by the combination of 3D printing and electrospinning techniques. Skeletal muscle cells cultured on these modular scaffold bricks exhibited a highly orientated nanofibrous structure. A variety of construction of skeletal muscle tissues further enabled development by various assembling processes. Moreover, skeletal muscle-on-a-chip (SMoC) was further assembled as a functional platform for electrical or perfusion stimuli investigation. The electrical stimulus was conveniently applied and tuned in such a SMoC platform to significantly enhance the differentiation of skeletal muscle tissues. Additionally, the effect of perfusion stimulation on skeletal muscle vascularization within the SMoC platform was also demonstrated. These findings highlight the potential of these assembled SMoCs as functional ex vivo platforms for skeletal tissue engineering and drug research applications, and such a LEGO-like assembly strategy could also be applied to the other engineering organ-on-chips fabrication, which facilitates the development of bionic functional platforms for various biomedical research applications.
We developed a list of modular nanofibrous scaffold bricks by a hybrid fabrication method combining 3D printing and electrospinning techniques, featuring precise microscale and nanoscale structures. Emulating the LEGO-like assembly method, these bricks were assembled along the x–y–z axis to mimic various skeletal muscle structures. These developed engineered skeletal muscle tissues were further integrated into the microfluidic chip to develop the skeletal muscle-on-a-chip (SMoC) as an in vitro testing platform for both electrical and perfusion stimuli investigation.
Smart data gloves capable of monitoring finger activities and inferring hand gestures are of significance to human–machine interfaces, robotics, healthcare, and Metaverse. Yet, most current smart data gloves present unstable mechanical contacts, limited sensitivity, as well as offline training and updating of machine learning models, leading to uncomfortable wear and suboptimal performance during practical applications. Herein, highly sensitive and mechanically stable textile sensors are developed through the construction of loose MXene-modified textile interface structures and a thermal transfer printing method with the melting-infiltration-solidification adhesion procedure. Then, a smart data glove with adaptive gesture recognition is reported, based on the integration of 10-channel MXene textile bending sensors and a near-sensor adaptive machine learning model. The near-sensor adaptive machine learning model achieves a 99.5% accuracy using the proposed post-processing algorithm for 14 gestures. Also, the model features the ability to locally update model parameters when gesture types change, without additional computation on any external device. A high accuracy of 98.1% is still preserved when further expanding the dataset to 20 gestures, where the accuracy is recovered by 27.6% after implementing the model updates locally. Lastly, an auto-recognition and control system for wireless robotic sorting operations with locally trained hand gestures is demonstrated, showing the great potential of the smart data glove in robotics and human–machine interactions.
Wearable electronics based on natural biomaterials, such as bacterial cellulose (BC), have shown promise for a variety of healthcare and human-computer interaction applications. However, current BC-based pressure sensors have an inherent limitation, which is the two-dimensional rigid structures and limited compressibility of BC restrict the sensitivity and working range for pressure sensing. Here, we propose a strategy for fabricating BC/polypyrrole/spacer fabric (BPSF) pressure sensors with a hierarchical structure constructed by integrating conductive BC nanonetwork into a compressible fabric frame via the in situ biofermentation process. The hierarchical structure design includes a cross-scale network from the nanoscale BC sensor networks to the macroscopic three-dimensional compressible fabric sensor network, which significantly improves the working range (0–300 kPa) and sensitivity (40.62 kPa−1) of BPSF. Via this unique structural design, the sensor also achieves a high fatigue life (~5000 cycles), wearability, and reproducibility even after several washing and abrasion cycles. Furthermore, a flexible and wearable electronic textile featuring an n × n sensing matrix was developed by constructing BPSF arrays, allowing for the precise control of machines and weight distribution analysis. These empirical insights are valuable for the biofabrication and textile structure design of wearable devices toward the realization of highly intuitive human-machine interfaces.
Solar-driven seawater evaporation is a potential strategy for mitigating global freshwater shortage, but its application is hindered by the photothermal membranes with high evaporation enthalpy, unsatisfactory photoabsorption, and easy contamination by microorganism. To solve these problems, herein we reported the design of manganese oxide/poly-L-lysine co-decorated carbon-fiber cloth (CFC) with decreased evaporation enthalpy and enhanced photoabsorption/antibacterial performance. Manganese oxide (MnO2) nanosheets (thickness: 10–30 nm, diameter: 400–450 nm) were grown in situ on the CFC surface by a hydrothermal method, and then the nanosheet surface was further decorated with poly-L-lysine (PLL) by the electrostatic adsorption. Co-decoration of MnO2/PLL confers the conversion of hydrophobic CFC to superhydrophilic CFC/MnO2/PLL, accompanied by the reduction of the evaporation enthalpy of bulk water to 2132.34 kJ kg−1 for CFC/MnO2/PLL sample. Such CFC/MnO2/PLL exhibits a strong photoabsorption in wide range (280–2500 nm) with an absorption efficiency of 97.8%, due to the light-trapping effects from hierarchical structures. Simultaneously, CFC/MnO2/PLL has excellent antibacterial performance toward E. coli (99.1 ± 0.2%) and S. aureus (98.2 ± 0.5%) within 60 min in the dark, due to the electrostatic interaction between the bacterial cell membrane and PLL. Subsequently, CFC/MnO2/PLL was hung between the seawater tank and empty tank to construct a hanging evaporator. Under 1.0 kW m−2 light irradiation, CFC/MnO2/PLL shows a preeminent evaporation rate of 2.20 kg m−2 h−1. Importantly, when germy NaCl solution is evaporated, there is no solid-salt accumulation and bacteria contamination on CFC/MnO2/PLL surface during the long-time test (12 h), conferring long-term anti-fouling seawater evaporation. Hence, this work provides new possibilities in the rational design of photothermal fabrics for solar-enabled efficient anti-fouling seawater desalination.
An advanced approach for functionalizing the surfaces of electrospun poly(l-lactide-co-ε-caprolactone) (PLCL) nanofibers for biomedical applications is presented here. Using initiated chemical vapor deposition (iCVD), a coating of the copolymer p(PFMA-co-DVB) containing poly(pentafluorophenyl methacrylate) (PFMA) and divinylbenzene (DVB) was applied to the PLCL nanofibers. This coating facilitated efficient immobilization of the biomolecules on the PLCL nanofiber surfaces, allowing precise adjustments to the polymer composition through modulation of the monomer flow rates. The resulting copolymer exhibited superior efficiency for immobilizing IgG, as confirmed by immunofluorescence intensity analysis. In vitro studies conducted with different neural cell types demonstrated that the laminin-coated iCVD-functionalized PLCL nanofibers maintained their inherent biocompatibility while significantly enhancing cell adhesion. By exploiting the elastic nature of the PLCL nanofibers, cell elongation could be successfully manipulated by controlling the nanofiber alignment, as demonstrated by scanning electron microscopy and quantification of the immunofluorescence image orientation. These findings highlight the potential of iCVD-modified PLCL nanofibers as versatile platforms for neural tissue engineering and various biomedical applications, allowing valuable biomaterial surface modifications for enhanced cellular interactions.
Microneedles (MNs) with unique three-dimensional stereochemical structures are suitable candidates for tissue fixation and drug delivery. However, existing hydrogel MNs exhibit poor mechanical properties after swelling and require complex preparation procedures, impeding their practical application. Hence, we engineered chitosan fiber-reinforced silk fibroin MN patches containing epigallocatechin gallate (SCEMN). A formic acid–calcium chloride system was introduced to fabricate hydrogel MNs with excellent inherent adhesion, and the incorporation of chitosan fiber as a reinforcing material enhanced mechanical strength and viscosity, thereby increasing the physical interlocking with tissue and the ability to maintain shape. The SCEMN with a lower insertion force firmly adhered to porcine skin, with a maximum detachment force of 11.98 N/cm2. Additionally, SCEMN has excellent antioxidant and antibacterial properties, facilitates macrophage polarization from M1 to M2, and demonstrates superior performance in vivo for diabetic wound repair compared with the commercial product Tegaderm™. This study represents the first trial of fiber-reinforced hydrogel MNs for robust tissue adhesion. Our findings underscore the significance of this innovative approach for advancing MN technology to enhance tissue adhesion and accelerate wound healing.
Owing to the high flexibility, low thermal conductivity, and tunable electrical transport property, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) exhibits promising potential for designing flexible thermoelectric devices in the form of films or fibers. However, the low Seebeck coefficient and power factor of PEDOT:PSS have restricted its practical applications. Here, we sequentially employ triple post-treatments with concentrated sulfuric acid (H2SO4), sodium borohydride (NaBH4), and 1-ethyl-3-methylimidazolium dichloroacetate (EMIM:DCA) to enhance the thermoelectric performance of flexible PEDOT:PSS fibers with a high power factor of (55.4 ± 1.8) μW m−1 K−2 at 25 °C. Comprehensive characterizations confirm that excess insulating PSS can be selectively removed after H2SO4 and EMIM:DCA treatments, which induces conformational changes to increase charge carrier mobility, leading to enhanced electrical conductivity. Simultaneously, NaBH4 treatment is employed to adjust the oxidation level, further optimizing the Seebeck coefficient. Additionally, the assembled flexible fiber thermoelectric devices show an output power density of (60.18 ± 2.79) nW cm−2 at a temperature difference of 10 K, proving the superior performance and usability of the optimized fibers. This work provides insights into developing high-performance organic thermoelectric materials by modulating polymer chains.
Fiber strain sensors with robust sensing performance are indispensable for human–machine interactions in the electronic textiles. However, current fiber strain sensors are confronted with the challenges of unavoidable deterioration of functional sensing components during wearable and extreme environments, resulting in unsatisfactory stability and durability. Here, we present a robust fiber strain sensor based on the mutual inductance effect. The sensor is assembled by designing coaxial helical coils around an elastic polyurethane fiber. When stretching the fiber sensor, the strain is detected by recording the voltage changes in the helical coils due to the variation in magnetic flux. The resultant fiber strain sensor shows high linearity (with a linear regression coefficient of 0.99) at a large strain of 100%, and can withstand various extreme environmental conditions, such as high/low temperatures (from − 30 °C to 160 °C), and severe deformations, such as twisting and pressing (with a pressure of 500 N/cm). The long-term cyclic stability of our fiber strain sensor (100,000 cycles at a strain of 100%) is superior to that of most reported flexible resistive and capacitive strain sensors. Finally, the mass-produced fiber strain sensors are woven into a smart textile system to accurately capture gestures.
Carbon fiber (CF) has emerged as a promising candidate for microwave absorbers to resolve the escalating electromagnetic wave (EMW) pollution issue, not just serving as a structural reinforcement. However, the drawbacks, such as high conductivity, limit its ability to strongly absorb EMWs over a wide bandwidth. To address these challenges, graphite wrapped FeNi3/Co with carbon nanotubes (CNTs) anchored on MgO@CF heterostructures were synthesized by introducing MgO nanofilms on a CF surface and subsequent chemical vapor deposition catalyzed by two-phase catalysts. The synthesis of MgO suppresses the etching of CF during the experimental processes, effectively maintaining the inherent structure of CF, which is conducive to constructing rich conductive networks and developing excellent mechanical properties. By modulating the catalyst concentration, deposited CNTs with appropriate defects increase the conduction loss and stimulate defect polarization loss. The abundant interfaces formed by multiple components lead to fulfilling interface polarization, while the doping of O heteroatoms causes dipole polarization. In addition, the introduction of FeNi3/Co generates effective magnetic loss and optimizes electromagnetic parameters to form more matching impedance conditions. At a low filler loading of 23 wt%, the stable sample obtains a remarkable minimum reflection loss of up to − 72.08 dB at merely 1.38 mm with an effective absorption bandwidth reaching 4.88 GHz at only 1.44 mm, which is superior to that of numerous distinguished carbon-based composites in regard to being “thin, light, wide and strong”. CST simulation reveals that the maximum radar cross section reduction acquires 26.88 dBm2, ascertaining the radar stealth capability of the distinctive heterostructure. Moreover, great mechanical and electromagnetic interference shielding performance is demonstrated by epoxy composites. Henceforth, this study proposes profound insights into the intricate relationship between the structure and EMW absorbing mechanism, and elucidates an attractive strategy for mass-producing modified CF-based hybrids for versatile applications.
Absorption-dominated electromagnetic interference (EMI) shielding fabrics are urgently needed to address the increasingly severe electromagnetic radiation pollution, especially the secondary radiation problem. In this study, we design novel core-sheath CNT@MXene fibers with a gradient conductive structure and corresponding fabrics to realize absorption-dominated EMI shielding performances. This coaxial structure utilizes carbon nanotubes (CNTs) as the sheath and MXene as the core and is constructed through a wet spinning technique. By virtue of the core-sheath structure, the conductive gradient structure in the fibers is easily optimized by adjusting the core MXene and sheath CNT content. This gradient conductive network of fiber effectively facilitates the incidence of electromagnetic waves and strong interactions between electromagnetic waves and the composites, resulting in excellent EMI absorption ability. Within the X-band frequency range, the fabric exhibits an electromagnetic interference shielding effectiveness of 23.40 dB and an absorption coefficient of 0.63. Due to the protection of polymer, the fiber’s electrical conductivity remains stable under conditions such as multi-cycle bending, stretching, and ultrasonic treatment, and in high relative humidity environments. Additionally, the fabric also demonstrates EMI shielding stability in indoor environments. This work indicates the great potential of the gradient structured fibers to achieve an absorption-dominated mechanism for next-generation eco-friendly EMI shielding fabrics.