Graphene-based Fiber Research Articles

Sol-gel fabrication and performance evaluation of graphene-based hydrophobic solid-phase microextraction fibers for multi-residue analysis of pesticides in water samples.

Widespread use of organophosphorus pesticides poses serious environmental threats, and hence calls for effective analysis methods for these classes of compounds. In this study, a lab-made graphene-based solid-phase microextraction (SPME) fiber was fabricated by the sol-gel method and combined with a gas chromatography-flame photometry detector (GC-FPD) to realize the detection of trace OPPs in water samples. Compared to the commercial fiber coatings, the new sol-gel graphene fiber coatings showed advantages of good durability and solvent resistance, which were attributed to the hydrophobic and antibacterial properties of the functionalized graphene and 3-(trimethoxysilyl)propyldimethyloctadecylammonium chloride (QAS). A headspace SPME method in combination with a GC-FPD was established to evaluate the performance of the novel fibers. The proposed method showed a good linear relationship for the eight OPPs (R2≥ 0.9957) in the concentration range of 1 to 1000 μg L-1, with limits of quantification of 0.11-3.37 μg L-1 and limits of detection of 0.03-1.01 μg L-1. Furthermore, the developed method also exhibited good recoveries for the analysis of OPPs both in rainwater and lake water, which demonstrates that this method is an alternative choice for multi-residue analysis of OPPs, and it has the potential for broader applications in the future.

Graphene-based fiber sensors with high stretchability and sensitivity by direct ink extrusion

Free-standing stretchable fibers with highly flexibility and sensitivity are the key components of the smart wearable electronic devices. In this work, one-dimensional graphene-based fibers with aligned morphology are fabricated by direct ink extrusion, in which graphene and poly(dimethyl siloxane) (PDMS) can be integrated into a conductive network. The graphene-based fibers can respond to multiple deformations such as bending, twisting, compressing, and stretching. The various response amplitude with a reversible electrical resistance change can be obtained from multiple strain cycles, which exhibits high sensitivity and broad range in strain sensing. The ultra-sensitive electromechanical property with a gauge factor of 65 under 6% strain is attributed to the interwoven graphene network and could be cycled 600 times of continuous stretching−releasing process with less than 6.2% attenuation in the response signal. The intrinsic dynamic fracture procedure and mechanism of graphene-based fibers are investigated as a result of the gradual growth of locally generated cracks. The controllable fabrication of graphene-based fibers with high sensitivity shows great potential applications in stretchable wearable sensors for real-time monitoring and distinguishing of human motion and gestures.

Non-woven fabric electrodes based on graphene-based fibers for areal-energy-dense flexible solid-state supercapacitors

Abstract Nowadays, lightweight, flexible, and wearable sustainable electric-power sources have attracted increasing attention due to the rapid development of portable electronics. Graphene fiber fabrics, as newly discovered carbon textiles, have exhibited attractive properties for wearable power devices. How to realize scalable construction of non-woven graphene-based fabric electrodes with high areal capacitance is challenging for portable electronics. Here, a novel coagulation bath fabrication technique was firstly reported to prepare reduced graphene oxide fiber fabrics (rGOFFs) for areal-energy-dense supercapacitors. The as-prepared rGOFFs showed high flexibility and conductivity. The symmetric supercapacitors (SCs) assembled with rGOFFs (95 μm) based fabric electrodes performed a high specific gravimetric capacitance (Cm) of 285 F/g at 0.1 A/g and 220 F/g at 1 A/g. The areal capacitance (Ca) of rGOFFs (220 μm) based electrode reached up to 2812 mF/cm2 at 1 mA/cm2. After electrochemical deposition of polyaniline (PANI) on rGOFFs (220 μm) substrate, the Ca of rGOFF@PANI – 220 μm based electrode was intensified to 3828 mF/cm2 at 1 mA/cm2 (172 F/cm3). The symmetric all-solid-state SCs showed an energy density from 28 μWh/cm2 (254 μW/cm2) to 11 μWh/cm2 (4950 μW/cm2). Overall, the as-designed rGOFFs based fabric electrodes and their fabrication techniques are of great potential for the next-generation multi-functional textile electronics.

Novel Flexible Material-Based Unobtrusive and Wearable Body Sensor Networks for Vital Sign Monitoring

The increased prevalence of chronic disease in aging population entails health risks and imposes significant economic and social burden. It is essential to provide comfortable, cost-effective, and easy-to-use unobtrusive and wearable systems for personal well-being and healthcare. Novel flexible material-based non-invasive and wearable sensors offer an efficient and cost-effective solution, which enables the continuous and real-time monitoring of important physiological signs of the human beings, the assessment of personal health conditions and that provides feedback from remote and home monitoring. In this paper, novel flexible material-based wearable sensors, devised into body sensor networks to capture and monitor vital bio-signals, including electroencephalography (EEG), electrocardiography (ECG) and respiratory, are proposed. Silver nanowires (Ag NWs) and polydimethylsiloxane composite material, carbon foam, and graphene-based fiber are used to sense the EEG, ECG, and respiratory, respectively. With different flexible materials, the smart hat and smart jacket are designed to affix the sensors, which enable long-term health monitoring of vital signals seamlessly. Meanwhile, the corresponding acquisition circuits are developed and mounted with the proposed electrodes on the garments. More importantly, a comprehensive protocol is designed to validate the performance of the proposed system, while some standard sensors and commercial devices are used for comparison. The evaluation results demonstrate the proposed system represents a comparable performance with the existing system. In summary, the proposed sensing system offers an unobtrusive, detachable, expandable, user-friendly, and comfortable solution for physiological signal monitoring. It can be expected to use for the remote healthcare monitoring and provide personalized information of health, fitness, and diseases.

Facile Interface Design Strategy for Improving the Uvioresistant and Self-Healing Properties of Poly(p-phenylene benzobisoxazole) Fibers.

Graphene-based coaxial hybrid fibers (CHFs) with a typical core-sheath structure have attracted extensive attention in recent years because of their potentially excellent mechanical performance. However, direct introduction of the micrometer-thick graphene stack structure on the extremely inert fiber surface with little negative effect has barely been reported so far and is still a great challenge. In the present work, a facile and cost-efficient dimensionally confined hydrothermal reduction, static adsorption, and thermal-assisted shrinkage sequential treatment strategy was developed to fabricate one-dimensional CHFs. The large-scale reduced graphene oxide-metal organic framework (RGO-UIO-66) hybrid layer and poly(p-phenylene benzobisoxazole) (PBO) fiber serve as the sheath part and core part, respectively, and the final product is denoted as PGU-CHFs. The experimental results confirmed that the prepared monofilament composite with thermoplastic polyurethane (PGU-CHF-TPU) exhibited an excellent and stable intrinsically self-healing efficiency (about 85%) over 5 cycles and an extraordinary uvioresistant performance (increased by 128%) compared to those of pristine PBO fibers after 288 h UV aging irradiation. Moreover, the anti-ultraviolet (UV) properties of PGU-CHFs at 96 h are basically at the optimum level among most of the reported literatures at present after comparison. The highly near-infrared photothermal conversion ability and stability of micrometer-thick RGO stack structure and the synergism of RGO-UIO-66 hybrid sheath layer including UV adsorption, shielding attenuation, and reflection are responsible for the satisfactorily interfacial self-healing efficiency and UV-resistance properties of PGU-CHFs, respectively. Considering the diversities and versatilities of RGO and MOFs, the proposed fabrication strategy will promisingly endow PBO fibers with great application potential in the other fields such as fiber-based sensors and smart fibers.

Effect of pyrolyzed catecholamine polymers for concurrent enhancements of electrical conductivity and mechanical strength of graphene-based fibers

Graphene fibers are regarded as a novel platform material for flexible electronic applications based on their superior electrical conductivity, mechanical properties and potential for mass production. However, properties of graphene fibers are still far from commercial level and considerable effort has been made recently to improve these characteristics. In this paper, we drastically enhanced both the mechanical and electrical properties of graphene-based fibers by converting infiltrated polydopamine (PDA) into N-doped graphitic layers. Graphene-based fibers were fabricated from a liquid crystalline graphene oxide dispersion, and PDA was introduced into the fibers. After pyrolysis, the mechanical properties, i.e., the tensile strength and Young's modulus, of the composite graphene-based fibers exhibited 3.56- and 3.95-fold increases, respectively, compared with those of pristine graphene fibers. Furthermore, the electrical conductivity also dramatically increased to 7.3 × 104 S/m, which is almost 10 times that of pristine graphene fibers. These results show the achievement of advantages superior to those in previously reported studies based on polymer-grafted graphene composite fibers. This hybridized composite fabrication process provides a new way of reinforcing graphene fibers and contributes to expanding the application of graphene-based fibers in flexible electronic devices.

Graphene-Based Fibers: Recent Advances in Preparation and Application.

Graphene-based fibers (GBFs) are macroscopic 1D assemblies formed by using microscopic 2D graphene sheets as building blocks. Their unique structure exhibits the same merits as graphene such as low weight, high specific surface area, excellent mechanical/electrical properties, and ease of functionalization. Furthermore, the fibrous nature of GBFs is intrinsically compatible with existing textile technologies, making them suitable for applications in flexible and wearable electronics. Recently, novel synthetic methods have endowed GBFs with new structures and functions, further improving their mechanical and electrical properties. These improvements have rapidly bridged the gaps between laboratory demonstrations and real-life applications in fiber-shaped batteries, supercapacitors, and electrochemical sensors. Recent advances in the fabrication, optimization, and application of GBFs are systematically reviewed and a perspective on their future development is given.

Preparation of graphene oxide/polyacrylonitrile fiber from graphene oxide solution with high dispersivity

ABSTRACTThis paper reports the grafting of polyacrylonitrile (PAN) onto the functional groups of graphene oxide (GO) by bridge linkers, toluene diisocyanate (TDI) in high concentration GO solution to prepare GO/PAN composite fiber. In this study, it was discovered that GO solution with high dispersivity is rich in oxygen-containing functional groups and the well-dispersed GO exists as multi-layer graphenes and does not display liquid crystallinity. These factors contribute to the high dispersivity of the GO solution and spinning difficulty. To overcome these issues, TDI was used to bridge the easily spinnable PAN and rich oxygen-containing functional groups in GO. IR spectra confirmed that the TDI successfully linked PAN and GO with enhanced binding. Wet spinning was then used to spin the bridge-linked GO solution into GO/PAN composite fiber. SEM and Raman spectroscopy were used to characterize the fiber surface and carbon structure, respectively. The GO/PAN composite fiber prepared by wet spinning in an ethanol coagulation bath exhibited less folding, higher compactness, a lower degree of structural defects, and a uniform distribution of high GO content in the fiber. The interconnected graphene network shows potential for application as a graphene-based composite fiber with high thermal conductivity.

Functional & enhanced graphene/polyamide 6 composite fiber constructed by a facile and universal method

Demand for multifunctional and high-strength fiber has substantially increased in textile industry, biomedical, and biotechnological applications. In this study, an efficient and environment-friendly method was developed for functionalizing graphene through weak interaction and the construction of polyamide 6 composite functional fiber. With a loading of 0.5 wt% functionalized graphene oxide, the tensile strength reached 4.21 cN/dtex, and the tensile modulus reached 33.86 cN/dtex, indicating 31.6% and 33.6% enhancement, respectively. Moreover, the UV protection factor increased to more than 471, and the antibacterial property also increased to a certain level (antibacterial efficacy (AE)% >94%) with a low addition (0.9 wt%) of functionalized graphene oxide, indicating that the fabric can effectively prevent the encroachment of bacteria. These functionalization and composite preparation methods provide a convenient and scalable route to prepare graphene-based nanocomposite fiber with high strength and multifunctional properties. It has promising practical application in textile, biomedical, and biotechnological fields.

Ultrahigh Performance of Nanoengineered Graphene-Based Natural Jute Fiber Composites.

Natural fibers composites are considered as a sustainable alternative to synthetic composites due to their environmental and economic benefits. However, they suffer from poor mechanical and interfacial properties due to a random fiber orientation and weak fiber–matrix interface. Here we report nanoengineered graphene-based natural jute fiber preforms with a new fiber architecture (NFA) which significantly improves their mechanical properties and performances. Our graphene-based NFA of jute fiber preform enhances the Young modulus of jute–epoxy composites by ∼324% and tensile strength by ∼110% more than untreated jute fiber composites, by arranging fibers in a parallel direction through individualization and nanosurface engineering with graphene derivatives. This could potentially lead to manufacturing of high-performance natural alternatives to synthetic composites in various stiffness-driven applications.

CoNi-layered double hydroxide array on graphene-based fiber as a new electrode material for microsupercapacitor

Fiber-shaped supercapacitors (FSSCs) have attracted increasing interest owing to their advantages of lightweight, high flexibility and tiny volume. However, the practical application of FSSCs is still obstructed by their relatively low energy density and poor cycling stability. Herein, we report the design and fabrication of a well-aligned hollow fiber electrode via a two-step procedure, which involves the preparation of reduced graphene oxide (RGO) hollow fibers in capillary glass tubes and following in situ electrodeposition of CoNi-layered double hydroxide (LDH) nanoplate arrays on RGO. The resulting RGO@CoNi-LDH fiber electrode displays excellent electrochemical performance including high capacitance (570 mF cm−2) and good cycling stability (95.3% retention after 2000 cycles), as well as admirable mechanical property and wearable capability. By using this hollow fiber as positive electrode, a flexible all-solid-state asymmetric FSSCs was further obtained, which shows high energy density (8.89 μWh cm−2 at power density of 0.525 mW cm−2) and long-term bending durability. The energy and power densities are in the highest level among those of the reported FSSCs. Therefore, this work provides a new method for the construction of hybrid fiber electrodes for high-performance microsupercapacitors, which show a broad application prospects in next-generation wearable electronics.

Graphene-Based Waist-Enlarged Optical Fibre Sensor for Measurement of Sucrose Concentration

Abstract A novel sucrose sensor based on graphene-coated optical fibre with waist-enlarged bitapers as Mach-Zehnder interferometer is proposed and demonstrated. The sensor is formed by arc fusion splicing a photonic crystal fibre (PCF) sandwiched between two single-mode fibres (SMFs). The intermodal interference is achieved by two waist-enlarged fibre tapers at the coupling points between the PCF and two SMFs. The result shows that the dips of transmission spectra exhibit blue shift with the concentration increase of the sucrose, and the sensor has a high linear response (R2 = 0.98233) to sucrose with an excellent sensitivity of 3.36 pm/ppm in the range of 0–230 ppm. Additionally, the surface adsorption mechanism is also discussed. Such easily fabricated, cost-effective and small volume fibre interferometer could be used for sucrose sensing applications.

Externally pumped low-loss graphene-based fiber Mach-Zehnder all-optical switches with mW switching powers.

We propose and experimentally demonstrate an all-optical switch based on a graphene-coated fiber Mach-Zehnder interferometer, where the phase of the signal light in one arm of the interferometer is changed by the heat generated from external pump light absorption by the graphene coating. The external pumping scheme allows efficient pump absorption with multiple layers of graphene coated on an ordinary fiber or a slightly tapered fiber without introducing significant additional signal loss. Without using any wavelength multiplexer/demultiplexer, the switch can be pumped at any convenient wavelength or even with broadband light. Our experimental device, which is based on a standard 125-μm-diameter single-mode fiber with a 5-mm-long graphene coating, can be switched with a pump power of 5.3 mW at an extinction ratio of 19 dB with no additional signal loss. The switching power is insensitive to the graphene coating's length and can be reduced to 4.8 mW, with the fiber tapered to 40 μm. The measured switching powers agree well with the theoretical values obtained by treating the graphene coating as a uniform sheet of heat source without thickness. The switch's response time decreases with the fiber diameter and inversely with the graphene coating's length. The switch's rise and fall times, based on a 40-μm tapered fiber with a 20-mm-long graphene coating, are 30 ms and 50 ms, respectively.

An improved tin oxide core mismatch optical fiber sensor and its preparation method

Abstract A sensor was fabricated based on optical gas sensing, the sensitivity of tin oxide to methane via surface adsorption and electromagnetic theory. A 62.5/125 μm standard multimode fibre (MMF) and a 9/125 μm standard single-mode fibre (SMF) were spliced to fabricate a core diameter mismatch-based optical fibre methane sensor with an MM-SM-MM structure. The exposed fibre core areas were coated with graphene-doped tin oxide such that a novel graphene-based optical fibre methane sensor was fabricated. The experimental results show that the sensor exhibited a better linear fitting for greater reproducibility in the detection of low concentrations of methane than did the D-type gas sensor reported previously by the same authors.

基于石墨烯的光纤功能化传感器件和激光器件

基于石墨烯的光纤功能化传感器件和激光器件

Multifunctional reduced graphene oxide-CVD graphene core–shell fibers

The insufficient electrical conductivity and mechanical stretchability of conventional graphene fibers based on reduced graphene oxide liquid crystals (rGO-LCs) has limited their applications to numerous textile devices. Here, we report a simple method to fabricate multifunctional fibers with mechanically strong rGO cores and highly conductive CVD graphene shells (rGO@Gr fibers), which show an outstanding electrical conductivity as high as ∼137 S cm-1 and a failure strain value of 21%, which are believed to be the highest values among polymer-free graphene fibers. We also demonstrate the use of the rGO@Gr fibers for high power density supercapacitors with enhanced mechanical stability and durability, which would enable their practical applications in various smart wearable devices in the future.

Synthesis of P-Doped and NiCo-Hybridized Graphene-Based Fibers for Flexible Asymmetrical Solid-State Micro-Energy Storage Device.

Fiber supercapacitors (FSCs) are promising energy storage devices in portable and wearable smart electronics. Currently, a major challenge for FSCs is simultaneously achieving high volumetric energy and power densities. Herein, the microscale fiber electrode is designed by using carbon fibers as substrates and capillary channels as microreactors to space-confined hydrothermal assembling. As P-doped graphene oxide/carbon fiber (PGO/CF) and NiCo2 O4 -based graphene oxide/carbon fiber (NCGO/CF) electrodes are successfully prepared, their unique hybrid structures exhibit a satisfactory electrochemical performance. An all-solid-state PGO/CF//NCGO/CF flexible asymmetric fiber supercapacitor (AFSC) based on the PGO/CF as the negative electrode, NCGO/CF hybrid electrode as the positive electrode, and poly(vinyl alcohol)/potassium hydroxide as the electrolyte is successfully assembled. The AFSC device delivers a higher volumetric energy density of 36.77 mW h cm-3 at a power density of 142.5 mW cm-3 . In addition, a double reference electrode system is adopted to analyze and reduce the IR drop, as well as effectively matching negative and positive electrodes, which is conducive for the optimization and improvement of energy density. For the AFSC device, its better flexibility and electrochemical properties create a promising potential for high-performance micro-supercapacitors. Furthermore, the introduction of the double reference electrode system provides an interesting method for the study on the electrochemical performances of two-electrode systems.

Ultratough Bioinspired Graphene Fiber via Sequential Toughening of Hydrogen and Ionic Bonding

Graphene-based fibers synthesized under ambient temperature have not achieved excellent mechanical properties of high toughness or tensile strength compared with those synthesized by hydrothermal strategy or graphitization and annealing treatment. Inspired by the relationship between organic/inorganic hierarchical structure, interfacial interactions, and moderate growth temperature of natural nacre, we fabricate an ultratough graphene fiber via sequential toughening of hydrogen and ionic bonding through a wet-spinning method under ambient temperature. A slight amount of chitosan is introduced to form hydrogen bonding with graphene oxide nanosheets, and the ionic bonding is formed between graphene oxide nanosheets and divalent calcium ions. The optimized sequential toughening of hydrogen and ionic bonding results in an ultratough graphene fiber with toughness of 26.3 MJ/m3 and ultimate tensile strength of 743.6 MPa. Meanwhile, the electrical conductivity of the resultant graphene fiber is as high as 179.0 S/cm. This kind of multifunctional graphene fiber shows promising applications in photovoltaic wires, flexible supercapacitor electrodes, wearable electronic textiles, fiber motors, etc. Furthermore, the strategy of sequential toughening of hydrogen and ionic bonding interactions also offers an avenue for constructing high-performance graphene-based fibers in the near future.

Electrochemical performance of flexible graphene-based fibers as electrodes for wearable supercapacitors

The miniaturized supercapacitors are promising energy storage devices that can replace traditional batteries in portable electronics. Excellent graphene-based fibers have becoming a dominant role as electrode materials for supercapacitors. Unique and excellent carbon nanotubes and graphene composite fibers (G/CNTs) with outstanding mechanical properties and excellent capacitive behaviors were prepared by a facile, one-step and time-saving process. Scanning electron microscopy images displayed that the diameter of obtained G/CNTs was ∼150 μm, and showed a directional structure of graphene nanosheets and few-walled carbon nanotubes (FWNTs) along the specific direction of the as-prepared composite fibers. The electrochemical performances of the resultant fibers as flexible electrodes were estimated by a three-electrode system. The as-synthesized G/CNTs delivered a specific volumetric capacitance of 312.6 F g −1 at the current density of 200 mA g−1, and the capacitance of G10/CNTs could still remain at 89.6% of original capacitance after 10,000 cycles. Furthermore, the flexible G/CNTs could be fabricated into a stretchable and compressible fiber spring. The fiber supercapacitor displayed much efficient electrochemical capacitive behaviors, promising for being portable and wearable electronics, and this development can potentially promote its application in other fields.

High-Performance Graphene-Based Natural Fiber Composites.

Natural fiber composites are attracting significant interest due to their potential for replacing synthetic composites at lower cost with improved environmental sustainability. However, natural fiber composites suffer from poor mechanical and interfacial properties. Here, we report coating of graphene oxide (GO) and graphene flakes (G) onto natural jute fibers to improve mechanical and interfacial properties. The coating of graphene materials onto jute fibers enhanced interfacial shear strength by ∼236% and tensile strength by ∼96% more than untreated fibers by forming either bonding (GO) or mechanical interlocking (G) between fibers and graphene-based flakes. This could lead to manufacturing of high-performance and environmental friendly natural fiber composites that can potentially replace synthetic composites in numerous applications, such as the automotive industry, naval vessels, household products, and even in the aerospace industry.