For the optimal functional recovery of force-transmitting connective tissues, obtaining grafts that are mechanically robust and integrating them with host bone effectively to tolerate high loads during violent joint motions is both crucial and challenging. Recent research proposes that a hierarchical helical carbon nanotube fiber, which has the considerably high mechanical strength, and can integrate with the host bone and restore movement in animals, is a very promising artificial ligament. The above research marks a significant development in artificial ligament via the innovative utilization of hierarchical helical carbon nanotube fiber.
Soft fluidic devices are important for wearable applications involving mass and heat transfer. Based on charge injection electrohydrodynamics, a fluidic fiber pump made of polyurethane and copper wires has been reported to show outstanding performances in terms of pressure, flow rate and power density. Its flexible fiber shape allows integration compatible with textiles, opening new possibilities in the ever-growing field of wearable technology.
Cellulose-based fabrics are ubiquitous in our daily lives. They are the preferred choice for bedding materials, active sportswear, and next-to-skin apparels. However, the hydrophilic and polysaccharide characteristics of cellulose materials make them vulnerable to bacterial attack and pathogen infection. The design of antibacterial cellulose fabrics has been a long-term and on-going effort. Fabrication strategies based on the construction of surface micro-/nanostructure, chemical modification, and the application of antibacterial agents have been extensively investigated by many research groups worldwide. This review systematically discusses recent research on super-hydrophobic and antibacterial cellulose fabrics, focusing on morphology construction and surface modification. First, natural surfaces showing liquid-repellent and antibacterial properties are introduced and the mechanisms behind are explained. Then, the strategies for fabricating super-hydrophobic cellulose fabrics are summarized, and the contribution of the liquid-repellent function to reducing the adhesion of live bacteria and removing dead bacteria is elucidated. Representative studies on cellulose fabrics functionalized with super-hydrophobic and antibacterial properties are discussed in detail, and their potential applications are also introduced. Finally, the challenges in achieving super-hydrophobic antibacterial cellulose fabrics are discussed, and the future research direction in this area is proposed.
The figure summarizes the natural surfaces and the main fabrication strategies of superhydrophobic antibacterial cellulose fabrics and their potential applications.
Metal–organic frameworks are linked by different central organic ligands and metal-ion coordination bonds to form periodic pore structures and rich pore volumes. Because of their structural advantages, metal–organic frameworks are considered to be one of the most promising candidates for new energy storage materials. To better utilize their advantages, metal–organic frameworks can be combined with electrospinning technology to effectively adjust the porosity and mechanical strength of composite materials. This paper summarizes the combination of the latest metal–organic frameworks and classical spinning technology, starting from the structural design of electrode materials, and applying them to supercapacitors, lithium-ion batteries, lithium–sulfur batteries, sodium-ion batteries, and potassium-ion batteries. Finally, the problems and challenges related to the preparation of metal–organic framework nanofibers are summarized, and future development trends are predicted.
Carbon fibers (CFs) are widely used in various cutting-edge fields, such as aerospace, military, automobiles, and sports, owing to their unique combination of excellent mechanical properties, good thermal stability, and lightweight. However, their inherent super-black appearance makes it difficult to satisfy the aesthetic/fashion requirements of the colorful world, and the flammability of CFs severely limits their practical utilization in high-temperature and other extreme environments. Herein, we fabricated full-color tunable colored CFs on a large-scale via atomic layer deposition, based on the monolayer film interference strategy. CFs exhibited brilliant colors and excellent environmental durability in extreme environments, such as intense ultraviolet (UV) irradiation, accelerated laundering, friction, high-temperature, and low-temperature treatments. Colored CFs also exhibited excellent fire-retardant performance that could withstand alcohol-lamp flame burning for 60 min. Our work provides insights into an innovative material/structural design that can help achieve rapid development of the CF industry and global carbon neutrality/sustainability.
There is a growing need for protective instruments that can be used in extreme environments, including those encountered during exoplanet exploration, anti-terrorism activities, and in chemical plants. These instruments should have the ability to detect external threats visually and monitor internal physiological signals in real time for maximum safety. To address this need, multifunctional semiconducting fibers with visual detection ranging from yellow to red and near-field communication (NFC) capabilities have been developed for use in personal protective clothing. A composite conductive yarn with semiconducting fluorescent probe molecules is embroidered on the clothing, forming an NFC coil that allows for the visual monitoring of atmospheric safety through color changes. The fluorescence detection system was able to selectively detect diethyl chlorophosphate (DCP), a substitute for the toxic gas sarin, with a detection limit of 6.08 ppb, which is lower than the life-threatening concentration of sarin gas. Furthermore, an intelligent protective suit with the abovementioned dual functions was fabricated with good mechanical cycle stability and repeatability. Real-time physiological signals such as the temperature and humidity of the wearer could be read through the NFC conveniently. Such intelligent protective suits can quickly provide an early warning to the identified low-dose DCP and evaluate the health of wearer according to the changes in physiological signals. This study offers a smart, low-cost strategy for designing intelligent protective devices for extreme environments.
Fatigue-resistant and hysteresis-free composite fibers hold great promise for the next generation of wearable electronic devices. In this study, a novel approach for the fabrication of composite fibers with outstanding elasticity and mechanical stability is proposed. The design incorporates a heterogeneous hierarchical structure (HHS), which mimics the structure of arteries, to achieve enhanced fatigue resistance and hysteresis-free performance. The composite fibers, Ecoflex-polyacrylamide fibers (EPFs), are created through the combination of heterogeneous elastomers and strong interfacial coupling. The results show that the EPFs exhibit exceptional fatigue resistance, being able to withstand up to 10,000 load–unload cycles at strains of 300% without any noticeable changes in their mechanical properties. The potential applications of these EPFs are demonstrated through their use as strain sensors for monitoring human motion in both air and water, as well as in energy-harvesting e-textiles.
This paper proposes a novel approach for the fabrication of composite fibers with heterogeneous hierarchical structure by mimicking the structure of arteries, to achieve enhanced fatigue resistance and hysteresis-free performance. The composite fibers are created through the combination of heterogeneous elastomers and strong interfacial coupling. The results show that the fiber exhibit exceptional fatigue resistance, being able to withstand up to 10,000 load–unload cycles at strains of 300% without any noticeable changes in their mechanical properties. Demonstrations as strain sensors for monitoring human motion in both air and water, as well as in energy-harvesting e-textiles are performed, indicating the as-made fiber with an enormous potential uses in e-skin and wearable electronic devices.
As portable and wearable electronic devices are rapidly developing, there is an urgent need for flexible and robust thermally conductive electromagnetic interference shielding materials to address the associated electromagnetic pollution and overheating issues. Herein, multifunctional poly(p-phenyl-2,6-phenylene bisoxazole) nanofiber/boron nitride nanosheet/Ti3C2Tx MXene nanosheet (PBO/BN/MXene) composite papers are prepared by a gel microparticle-mediated ordered assembly process with the aid of vacuum-assisted filtration. Nacre-like “brick and mortar” structure, segregated structure and sandwich structure are integrated into the composite paper, so that efficient thermally and electrically conductive networks have been established. When the BN and MXene contents are 29.2 wt% and 41.7 wt%, the 13 μm thick composite paper exhibits an EMI shielding performance of 31.8 dB and a thermal conductivity of 26.1 W/mK, markedly superior to those of the control samples without the ordered structures. Meanwhile, because of the unique architecture and inherent advantages of the building blocks, the composite paper exhibits extremely low coefficient of thermal expansion (~ 1.43 ppm/K), excellent mechanical properties, and outstanding thermal stability and flame retardance, making it highly advantageous for practical applications in electronic devices. This work offers a promising approach for fabricating high-performance multifunctional composites by constructing efficient filler networks.
The integration of a display function with wearable interactive sensors offers a promising way to synchronously detect physiological signals and visualize pressure/stimuli. However, combining these two functions in a strain sensor textile is a longstanding challenge due to the physical separation of sensors and display units. Here, a water-stable luminescent perovskite hydrogel (emission band approximately 25 nm) is constructed by blending as-prepared CsPbBr3@PbBr(OH) with stretchable polyacrylamide (PAM) hydrogels. The facile introduction of CsPbBr3@PbBr(OH) endows the hydrogels with excellent optical properties and a high mechanical strength of 51.3 kPa at a fracture strain of 740%. Interestingly, the resulting hydrogels retain bright green fluorescence under conditions including water, ultraviolet light, and extensive stretching (> 700%). As a proof-of-concept, a novel wearable stretchable strain sensor textile based on these hydrogels is developed, and it displays visual-digital synergetic strain detection ability. It can perceive various motions on the human body in real time with electronic output signals from changes in resistance and simultaneously readable optical output signals, whether on land or underwater. This work provides a meaningful guide to rationally design perovskite hydrogels and accelerates the development of wearable visual-digital strain sensor textiles.
Nowadays, triboelectric nanogenerators (TENGs) are one of the most emerging technologies owing to their easy and cost-effective device structure. TENGs can harvest mechanical energy from our living environment. Herein, we synthesized dielectric zinc tin oxide (ZnSnO3) nanoparticles (NPs) by a hydrothermal technique. The ZnSnO3 NPs provide a dielectric and piezoelectric effect, which can efficiently enhance the output electrical performance of the proposed TENG. The prepared ZnSnO3 NPs were embedded into a polyvinylidene fluoride hexafluoropropylene (PVDF-HFP) polymer to prepare ZnSnO3/PVDF-HFP nanofibrous films to fabricate a TENG. The output performance of TENG was investigated and optimized by varying the loading concentration of ZnSnO3 NPs in PVDF-HFP fibrous films. The highest voltage, current, charge density, and power density from the fabricated TENG were achieved as ~ 138 V, ~ 5 µA, ~ 52 µC/m2, and ~ 1.6 W/m2, respectively. Additionally, the robustness of the TENG was studied via the long-term mechanical stability test. Finally, the practical and real-time application of the TENG was demonstrated by harvesting mechanical energy to power low-power portable electronic devices. Furthermore, the materials used in the TENG were combined into a skipping rope to harvest biomechanical/mechanical energy while exercising.
Electrospun materials have attracted considerable attention in microbial fuel cells (MFC) owing to their porous structures, which facilitate the growth of electro-active biofilms (EABs). However, the impact of fiber diameter-controlled porous architectures on EAB growth and MFC performance has not been extensively studied. Herein, a highly conductive polypyrrole-modified electrospun polyacrylonitrile (PAN) mat was prepared as an electrode material for Shewanella putrefaciens CN32-based MFCs. The dominant pore size of the corresponding mat increases from 1 to around 20 μm as the fiber diameter increases from 720 to 3770 nm. This variation affects the adhesion and growth behaviors of electrochemically active bacteria on the mat-based electrodes. The electrodes with pores ranging from 2 to 10 μm allow bacterial penetration into the interior, leading to significant biofilm loading and effective bioelectrocatalysis. However, the tight lamination of the electrospun fibers restricts bacterial growth in the deep interior space. We developed a friction-induced triboelectric expanding approach to rendering the mats with layered structures to overcome this limitation. The inter-layer spaces of the expanded conductive mat can facilitate bacterial loading from both sides of each layer and serve as channels to accelerate the catalysis of organic substances. Therefore, the expanded conductive mat with appropriate pore sizes delivers superior bioelectrocatalytic performance in MFCs and dye degradation. Based on the findings, a mechanism for the porous structure-controlled EAB formation and bioelectrocatalytic performance was proposed. This work may provide helpful guidance and insights for designing microfiber-based electrodes for microbial fuel cells.
With increasing personalized healthcare, fiber-based wearable temperature sensors that can be incorporated into textiles have attracted more attention in the field of wearable electronics. Here, we present a flexible, well-passivated, polymer–nanocomposite–based fiber temperature sensor fabricated by a thermal drawing process of multiple materials. We engineered a preform to optimize material processability and sensor performance by considering the rheological and functional properties of the preform materials. The fiber temperature sensor consisted of a temperature-sensing core made from a conductive polymer composite of thermoplastic polylactic acid, a conductive carbon filler, reduced graphene oxide, and a highly flexible linear low-density polyethylene passivation layer. Our fiber temperature sensor exhibited adequate sensitivity (− 0.285%/°C) within a temperature range of 25–45 °C with rapid response and recovery times of 11.6 and 14.8 s, respectively. In addition, it demonstrated a consistent and reliable temperature response under repeated mechanical and chemical stresses, which satisfied the requirements for the long-term application of wearable fiber sensors. Furthermore, the fiber temperature sensor sewn onto a daily cloth and hand glove exhibited a highly stable performance in response to body temperature changes and temperature detection by touch. These results indicate the great potential of this sensor for applications in wearable, electronic skin, and other biomedical devices.
Thermoelectric (TE) textiles which can harvest thermal energy from the human body, are highly desirable and vital to the charging of wearable electronics owing to their stable and long-term power output. The typical carbon nanotube (CNT) yarns or bismuth telluride (Bi2Te3) based inorganic TE materials used hitherto limit the development of TE textiles, because of their high cost and rareness. In this work, scalable and high-TE performance carbon nanotube composite yarns (CNTYs) are developed using p- and n-type tuneable multi-wall CNTs and single-wall CNTs as TE materials and waterborne polyurethane (WPU) as the binder. The mechanical properties of the CNTYs are tuned and improved considerably by adding a small amount of WPU. Furthermore, TE yarns with p- and n-type segmented structures are prepared by treating CNTYs with poly(3, 4-ethylene dioxythiophene): polystyrene sulfonate solution and n-type dopant polyetherimide, respectively. Based on the prepared p- and n-type segmented TE yarns, a TE textile with 75 p–n pairs that achieve outstanding TE output is fabricated. The TE textile can generate a high power density of 95.74 μW m−2 with a voltage density of 3.76 V m−2 at a temperature difference of 32 K. It provides an output voltage of ~ 37 mV outdoors (~ 12 ℃) when worn on the arm and demonstrates potential application to electronic devices after amplification. The fabrication method used in this study is not only a low-cost, scalable for preparing high-performance TE yarns but also realizes the body heat harvesting and temperature sensing of yarn-based TE textiles.
Recently, waterproof lighting and luminescent displays have been achieved in perovskite–polymer composite materials. However, practical large-area display applications are still limited to the strong electrostatic adhesion (EA) and high productivity. To overcome these deficiencies, large-area (~ 600 cm2) homogeneous perovskite–polymer fiber membranes (PPFMs) are synthesized by an electrospinning strategy in this work. Due to the microscopic cladding of the hydrophobic polymer fibers, the electrospun PPFMs exhibit ultrastable underwater luminescence for more than 90 days, and strong EA to diverse materials without pretreatments or additional adhesives. Moreover, by utilizing a proposed programmable laser lithography strategy, designed PPFM patterns are fabricated as the assembly blocks of large-area colorful or tridimensional displays. Interestingly, due to laser thermal ablation effects, the disengaged edges of these blocks are self-stitched with high mechanical stability and operability. This work provides a simple and effective strategy to realize waterproof, self-adhesive, and large-area display applications of perovskite nanomaterials in real world settings.
Large-area perovskite–polymer fiber membranes are synthetized by an electrospinning strategy. Underthe microscopic cladding of hydrophobic polymer fibers, the composite membranes of perovskite nanocrystals fully embedded exhibit ultrastable underwater luminescence for more than 90 days, it also demonstrates excellent flexibility and good self-adhesion to diverse materials. Moreover, designed colorful membrane patterns can be fabricated by a proposed programmable laser lithography strategy, and used as assembly blocks of large-area two-dimensional or tridimensional displays.
Carbon-based fibrous supercapacitors (CFSs) have demonstrated great potential as next-generation wearable energy storage devices owing to their credibility, resilience, and high power output. The limited specific surface area and low electrical conductivity of the carbon fiber electrode, however, impede its practical application. To overcome this challenge, this study fabricated a CFS by sequentially coating graphene, carbon nanotube, and activated carbon on the carbon fiber surface (CF/G/CNT/AC). The CF/G/CNT/AC exhibited excellent electrochemical performance with a specific capacitance of 692 mF cm–2 at 70 μA cm–2 and good cycling stability over 4000 cycles. This result is ascribed to the increase of contact area between the active material and the current collector. Moreover, the energy density of the as-prepared CF/G/CNT/AC fibrous supercapacitor reaches 86.6 and 37.7 μW cm–2 at power densities of 126 and 720 μW cm–2, respectively, demonstrating its potential for practical applications. In addition, the CF/G/CNT/AC demonstrated favorable traits such as mechanical flexibility, feasibility, and energy storage capacity, qualifying it as a viable alternative for wearable electronic textiles.
Stretchable supercapacitors (S-SCs) are of considerable interest as prospective energy-storage devices for wearable electronics and smart products. However, achieving high energy density and stable output under large deformations remains an urgent challenge. Here, we develop a high-performance S-SC based on a robust heterostructured graphene–polyaniline (G-PANI) anchored hierarchical fabric (G-PANI@pcPU). By precisely manipulating centrifugal electrospinning and PANI-induced two-step self-assembly process, the G-PANI@pcPU features an inter-linkage porous backbone, which open ions migration/intercalation pathways, high mechanical flexibility (elongation: 400%), and large production area (> 90 cm2). The resultant G-PANI@pcPU presents ultra-large specific areal capacitance (Careal) of 5093.7 mF cm−2 (about 35 mg cm−2 mass loading of G-PANI) and redox reversibility in 1 M H2SO4 electrolyte. Additionally, the G-PANI@pcPU fabric-based solid-state S-SCs show a high energy density of 69.2 μWh cm−2 and capacitance of 3113.7 mF cm−2. More importantly, the superior stretchable stability (84.1% capacitance retentions after 5000 cycles) and foldable performance (86.7% capacitance retentions after 5000 cycles) of S-SCs are impressively achieved. Finally, the S-SCs realize potential applications of steady powering light-emitting diode (LED) lights at 100% strain, smart watch at bending deformation, toy car, and lamp. This work can offer an overwhelming foundation for designing advanced flexible electrodes toward new energy and smart wearable applications.
Cellular respiration can provide energy for wound healing. However, some of retarded healing processes in local hyperglycemic environment suffer from a decrease in cellular adaptation to oxygen, thus reducing in situ oxidative metabolism. Herein, a three-dimensional (3D) extracellular matrix (ECM) bionic short fibrous sponge was prepared for chronic diabetic wound healing and effectively regulated cellular respiration by enhancing cellular adaptation to oxygen and remolding the local tissue microenvironment. The 3D bionic sponge scaffold exhibited good cell adhesion, biocompatibility, bioactivity, and, most importantly, aggregated oxygen atoms on the graphene oxide (GO) surface. In an in vitro assay, the oxygen atom-concentrating short fibrous sponge activated monocyte chemoattractant protein-1 (MCP-1), induced the expression of vascular endothelial growth factor (VEGF), and effectively promoted angiogenesis in a hyperglycemic environment. The sponge was also applied to diabetic wounds in vivo to verify its roles in the promotion of angiogenesis and collagen deposition. These experiments confirmed the synergistic effect of GO with adipose-derived stem cells (ADSCs), which could further promote diabetic wound healing. Therefore, oxygen atom-concentrating short fibrous sponges that regulate cellular respiration provide a new idea for the repair of poorly healing wounds by improving oxidative metabolism and have importantclinical significance.
The oxygen-rich characteristics of short fibrous sponges with aggregational oxygen atoms can optimize the water absorption performance of short fibers, effectively regulate cell respiration and improve tissue oxidation metabolism by improving the ability of cells to adapt to oxygen, and provide important application value for tissue damage repair in collaboration with ADSCs.
Heating, ventilation, and air conditioning (HVAC) systems account for one-third of the total energy consumption in office buildings. The use of airflow measurements to control the operation of HVAC systems can reduce energy consumption; thus, a sensor capable of monitoring airflow in a duct system is critical. Triboelectric nanogenerators (TENGs) can be utilized as self-powered sensors in airflow-driven TENGs (ATENGs) as self-powered sensors. By employing ferroelectric materials and surface modifications, the surface charges of TENGs can be increased. In this study, fibrous-mat TENGs were prepared using ferroelectric materials consisting of poly (vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) and polyamide 11 (nylon-11). And these materials were subsequently investigated. Poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) was added to PVDF-TrFE to enhance the ferroelectric crystalline phase. X-ray diffraction analysis revealed that this incorporation affects the β phase. In addition, the surface of nylon-11 was modified using the electrospray technique for post-treatment, thereby improving the interfacial adhesion between the fibers. These materials were then utilized in fibrous-mat ATENGs (FM-ATENGs) to demonstrate their practical application. The FM-ATENGs can be effectively used in an Arduino airflow-check sensor, showcasing their potential for application in HVAC systems, to enhance airflow control and energy efficiency.
Perovskite solar cells in a fiber format have great potential for wearable electronics due to their excellent flexibility, efficient light harvesting, and potentially high power conversion efficiency (PCE). However, the fabrication of large-sized fiber perovskite solar cells (FPSCs) while maintaining high efficiency remains a major challenge because of the difficulty in the formation of uniform crystalline perovskite films on highly curved surfaces. Here, we report a scale-up automatic approach for the fabrication of large-sized FPSCs via sequential coating of active layers on fiber substrates and posttreatment of perovskite films. We focus on understanding the perovskite film formation process on fibers and manage to control the film thickness, morphology, and crystallinity by adjusting the coating speed, precursor solution aging time, and posttreatment. As a result, a 20.0-cm-long FPSC with a PCE of 7.63% is achieved, and this length is almost ten times longer than those of the previously reported FPSCs. Our work represents a breakthrough in fabricating large-sized high-efficiency FPSCs, which will ultimately lead to practical applications of FPSCs.
Photothermal therapy (PTT) has been proposed as an advanced patient-centered strategy for tumor treatment. Nevertheless, the uncertain safety of conventional photothermal conversion agents and the presence of intracellular self-protective autophagy mechanisms pose obstacles to the clinical application and efficacy of PTT. As we are deeply aware of the seriousness of these problems, we herein proposed an efficacy-enhancing strategy based on an implantable membrane platform (PPG@PB-HCQ) constructed from poly (lactic acid) (PLA), poly (ɛ-caprolactone) (PCL) and gelatin (Gel) electrospun nanofibers (PPG) and loaded with the biodegradable high-efficiency photothermal conversion agent Prussian blue (PB) and the autophagy inhibitor hydroxychloroquine sulfate (HCQ). Cellular experiments confirmed that the PPG@PB-HCQ nanofiber membrane exhibited a significantly stronger tumor cell-killing effect compared with the PTT alone. This enhancement features by of blocking the fusion of autophagosomes with lysosomes. The intracellular overexpression of the proteins microtubule-associated protein 1 light chain 3 (LC3)-II and p62 and the low expression of the proteins LC3-I and Rab7 (members of the RAS oncogene family) further demonstrated autophagic flux blockade. Importantly, the potent antitumor effect of the PPG@PB-HCQ therapeutic platform in B16 tumor-bearing model mice verified the efficacy-enhancing strategy of synergistic PTT and protective autophagy blockade. The present study provides a promising strategy for solving the difficulties of tumor treatment, as well as a new perspective for designing novel treatment platforms.