Conductive Fibers Research Articles

Enhancement of electromagnetic interference shielding properties of hemp fiber sandwiched carbon fiber composites using electroless NiP coating

The present study aimed to improve the electromagnetic interference (EMI) shielding effectiveness (SE) of woven hemp fiber (HF) sandwiched carbon fiber (CF) epoxy composites using electroless Nickel-phosphorus coating. Furthermore, the phase composition, functional groups, microstructure, elemental composition, mapping and electrical conductivity of the raw fiber and coated fiber were analyzed in detail. Three different composite samples were prepared and their EMI SE was studied using a key sight 9374A vector network analyzer with 8–12 GHz frequency band (X-band frequency). The EMI SET of the raw HF sandwiched CF composite (S1) was observed as 61.17 dB. But, the addition of 1-layer coated HF between CF (S2) has increased the EMI SET from 61.17 to 83.16 dB. The 2 layer coated HF between CF (S3) had exhibited 92.77 dB which is 51.66 % higher than the S1 composite.

Research on the thermal conductivity and mechanical properties of carbon fiber reinforced thermoplastic composites doped with different sizes carbon nanotubes: A combination of experiments, numerical simulations and multi‐objective optimization

AbstractWhile improving the thermal conductivity of composites, single‐size carbon nanotubes (CNT) often degrade their mechanical properties due to the agglomerates. To overcome this limitation, this study reported thermoplastic resin matrix composites synergistically reinforced with small, medium, and large‐size carbon nanotubes (S‐CNT, M‐CNT, and L‐CNT). Using the thermal conductivity (λ) and mechanical properties (flexural strength [F], compressive strength [C] and tensile strength [T]) as the response values, we conducted 21 sets of mixing design experiments and developed the associated quadratic term models. Further multi‐objective optimization was carried out for the above response values. Optimized multiscale CNT synergistically modified composites (S‐CNT, M‐CNT, and L‐CNT contents of 1.25, 7.02, and 2.56 wt%) exhibited a λ value of 1.168 W/mK, which was 121% higher than that of pure composite and also superior to the same content of S‐CNT‐ (1.031 W/mK), M‐CNT‐ (1.016 W/mK), and L‐CNT‐modified composites (0.983 W/mK). Additionally, the optimized composite demonstrated excellent mechanical properties (F = 1482 MPa, C = 848 MPa, and T = 1759 MPa), which were 13%, 11%, and 13% higher than those of the pure composites, respectively, and also surpassed those of the S‐CNT‐, M‐CNT‐and L‐CNT‐modified composites.Highlights Using three different scales of carbon nanotubes modified CF/PPBESK composites. Polynomial modeling of composite's thermal conductivity and mechanical properties. Synergistic interactions between carbon nanotubes to improve the composite's thermal conductivity and mechanical properties.

In Situ Synthesis of Liquid Metal Conductive Fibers toward Smart Cloth.

To meet the diverse needs of humans, smart cloth has become a potential research hotspot to replace traditional cloth. However, it is challenging to manufacture a flexible fabric with multiple functions. Here, we introduce a smart cloth based on liquid metal (LM) conductive fibers. Ga2O3 nanoparticles are obtained through ultrasonic pretreatment. Furthermore, a coordination bond is formed between thiol groups on the surface of protein fibers and Ga2O3 through a scraping method, allowing Ga2O3 particles to be grafted onto the surface of protein fibers in situ. Finally, LM conductive fibers are encapsulated using a photocuring adhesive. In addition, a wearable smart cloth integrated with multiple sensors has been developed based on LM conductive fibers. Users can not only monitor their movement trajectory and the surrounding environment in real time but also have their data supervised by family members through a client, achieving remote and continuous monitoring. The development of this wearable smart cloth provides strong support for future wearable, flexible electronic devices.

GUIDEWIRE SHAPE MODIFICATION: A SIMPLE TECHNIQUE TO PREVENT CONDUCTION SYSTEM INJURIES DURING TRANSCATHETER VALVE IMPLANTATION

Abstract Background Atrioventricular (AV) conduction abnormalities remain one of the important unsolved issues with transcatheter aortic valve implantation (TAVI). To minimize trauma on the conduction fibers, we introduced a simple technique involving the bending of the stiff guidewire wire at the level of the arch to prevent and minimize contact with the interventricular septum. Aim To report the technique for shape manipulation of the stiff guidewire during TAVI and to evaluate its safety and effectiveness in reducing the need for permanent pace–make implantation after TAVI. Methods and Results Before insertion into the left ventricle the TAVI stiff wire was bended by hand to obtain a ³180° degree curve 15–20cm from its tip. Distance between stiff wire and septum was assessed in cranial–lao cusp overlap projection. Among 26 consecutive patients who underwent TAVI with a bended stiff wire, 13(50%) presented preoperative factors of increased risk for need of PM implantation after TAVI due to LVOT calcification (10, 38.5%), bicuspid aortic valve with raphe opposite to the septum (2, 7.7%) and baseline RBBB (2, 7.7%). Wire was observed to be distant from the septum >5mm in 22/26 (85%) cases. Median distance from septum was 9.0 [6.0, 12.0] mm. Pre–dilatation was required in 20 patients (77%). Balloon was observed to inflate distant from septum in 18 (90%) of them. Self–expandable valves were most frequently employed (n = 21, 81%).No patient required new PM implantation after TAVI. The two patients with baseline RBBB developed transient complete AVB, which recovered before discharge.No major complication (vascular, ventricular perforation, annular rupture, device embolization) was observed. Conclusions In this early preliminary experience stiff wire bending was able not only to keep far from the septum the wire in the majority of patients, without any complication, but also to provide wire stability and prevented inadvertent pressure of the wire over the left ventricular apex. No patient required PM implantation after TAVI. While wire bending seems promising in minimizing trauma on the conduction system, this study is to be considered hypothesis generating and more data are needed to confirm its findings.

Facile Fabrication of SrTiO3/In2O3 on Carbon Fibers via a Self-Assembly Strategy for Enhanced Photocatalytic Hydrogen Production

Photocatalytic water splitting by semiconductors is considered a promising and cost-effective method for achieving sustainable hydrogen production. In this study, a CF/SrTiO3/In2O3 photocatalytic material with a double-layer core–shell structure was developed. The experimental results indicated that the produced CF/SrTiO3/In2O3 composite fiber displayed superior photocatalytic hydrogen production performance, achieving a hydrogen evolution rate of approximately 320.71 μmol/g·h, which is roughly seven times higher than that of the CF/SrTiO3 fiber alone. The enhanced photocatalytic activity of the CF/SrTiO3/In2O3 fiber can be attributed to the heterojunction structure enriched with oxygen vacancies. It was found that these oxygen vacancies created defective states that served as traps for photogenerated electrons, facilitating their migration to the surface defect states and enabling the reduction of H+ in water to produce hydrogen. Furthermore, the synergy between the heterojunction structure and the conductivity of the carbon fiber promoted the generation and migration of photogenerated electrons, reduced the recombination of photogenerated electron–hole pairs, and ultimately improved photocatalytic hydrogen production. This study presents a new approach for designing efficient photocatalysts with surface oxygen vacancies on carbon fibers, providing new insights into the sustainable application of photocatalysts.

Ultra-strong and conductive graphene fiber via sacrificial layer technology

Microfluidic spinning technology (MST) is an emerging method specialized in the construction of multi-component and multi-structure fibers. In this study, we designed an ultra-strong coaxial graphene oxide (GO) fiber by employing sodium alginate (SA) as sheath flow via MST. The diameter of the fiber and the arrangement of GO molecules could be controlled by adjusting process parameters. More importantly, the outer SA layer could be removed during a subsequent reduction process of GO, which served as a sacrificial layer to GO fiber formation and enhanced the fiber strength. Ultimately, this could achieve a conductive graphene fiber with a maximum strength of 365.2 MPa and electrical conductivity of 52 Ω/cm via a common wet spinning mechanism.

Simultaneous measurement of thermal conductivity and emissivity of micro/nanomaterials

Although thermal conductivity of micro/nano scale material has been readily measured, the high specific surface area leads to non-negligible radiative heat transfer. Here, a method for simultaneous measurement of intrinsic thermal conductivity and emissivity of micro/nano materials was developed and verified. The physical model of this measurement principle consisted of two parallel platinum wires, which serve as both heaters and heat flux meters. Thermal conductivity and emissivity can be derived by comparing the changes in the average temperature rise of the heater and sensor platinum wires before and after attaching the test sample. The thermal conductivity and emissivity of an individual platinum wire were determined to 71.7 W/(m·K) and 0.14, which are consistent with the reference values. Subsequently, the thermal conductivity and emissivity of the polymer composite fiber were measured to be 1.45 W/(m·K), 0.73 and 1.87 W/(m·K), 0.8 at different composite filler concentrations. In principle, this method is applicable for accurately measuring the thermal transport properties of any micro/nano wires using appropriate sensors.

Biobased, recyclable, and multi-functional high-performance composites for electromagnetic interference shielding

High-performance fiber-reinforced thermoset composites (FRTCs) are highly demanded in modern society but are challenged because they depend on nonrenewable fossil-based feedstocks, are hard to recycle after service, and lack advanced functions. Here, we report a methodology to fabricate sustainable, recyclable, high-performance, and multifunctional FRTCs from renewable feedstocks such as vanillin, glycerol triglycidyl ether, 1,10-diaminodecane, and basalt fiber. We designed a mussel-inspired approach to prepare high conductive basalt fiber (CBF), and combined the CBF with a fully biobased covalent adaptable network (CAN) based on dynamic imine bonds to produce the composites i.e., CAN/CBF laminar composites through a solvent-free method. The CAN/CBF composites showed highly reinforced mechanical properties and multiple functionalities including electromagnetic interference shielding, shape memory, and self-adhesion characters through combination in the advantages and functions of both CAN and CBF. Furthermore, we demonstrated that the CAN matrix and the reinforced CBF can be recycled separately and can be further reformed to the CAN/CBF composites due to the dynamic nature of the CAN matrix. Our study thus provides an urgently applicable approach for advanced manufacturing toward the green and circular advanced composites economy.

Electrowriting patterns and electric field harness directional cell migration for skin wound healing

Directional cell migration is a crucial step in wound healing, influenced by electrical and topographic stimulations. However, the underlying mechanism and the combined effects of these two factors on cell migration remain unclear. This study explores cell migration under various combinations of guided straight line (SL) spacing, conductivity, and the relative direction of electric field (EF) and SL. Electrowriting is employed to fabricate conductive (multiwalled carbon nanotube/polycaprolactone (PCL)) and nonconductive (PCL) SL, with narrow (50 μm) and wide (400 μm) spacing that controls the topographic stimulation strength. Results show that various combinations of electrical and topographic stimulation yield significantly distinct effects on cell migration direction and speed; cells migrate fastest with the most directivity in the case of conductive, narrow-spacing SL parallel to EF. A physical model based on intercellular interactions is developed to capture the underlying mechanism of cell migration under SL and EF stimulations, in agreement with experimental observations. In vivo skin wound healing assay further confirmed that the combination of EF (1 V cm−1) and parallelly aligned conductive fibers accelerated the wound healing process. This study presents a promising approach to direct cell migration and enhance wound healing by optimizing synergistic electrical and topographic stimulations.

Age-associated changes in multimodal pain perception.

Pain sensitivity varies across multimodal somatosensory stimuli that can rely on different conductive fibres, which, when damaged, will lead to neuropathies. However, there is limited research examining the characteristics of perceived pain, particularly as affected by the ageing process, as induced by various somatosensory stimuli that may rely on small or large fibres. Using heat and pressure stimuli on small and large fibres separately on both younger and older adults, this study examined age-associated changes in pain perception by measuring self-reported pain sensitivity, pain threshold and pain discriminability. Heat pain threshold was significantly positively correlated with age, but not pressure pain threshold. Pain threshold increased and pain discriminability decreased in response to heat stimuli in the older participants compared with the younger ones. An age-associated decline in heat pain perception was observed, suggesting an earlier degradation of heat perception. These findings provide new insight into understanding and assessing somatosensory disorders, which can help ageing populations better maintain healthy sensory functioning.

A highly sensitive stretchable constraint fiber mat sensor with tailored near-zero Poisson’s ratio for very early stage of battery over charge/overdischarge monitoring

Battery state monitoring is crucial for safe operation and efficient management of lithium-ion battery (LIB) systems, but early stage of timely and accurate diagnosis remains challenging. Herein, we propose to utilize a highly sensitive stretchable strain sensor to in-situ monitor the slight strain variation of cells during charge and discharge, through which the state of the battery can be accurately reflected. The high sensing capability is realized by tailoring the Poisson’s ratio of low-modulus conductive fiber mats through a facile constraint manner. The non-uniform strain distribution together with the near-zero Poisson’s ratio synergistically result in the superior sensing performance, including ultralow strain detection limit (0.006%), high strain sensitivity particularly under small strains (gauge factor of 116.1 between 0 and 2% strain), and high strain resolution under large deformations. When being practically utilized for LIB monitoring, the constraint fiber mat sensor can produce instant resistance response reflecting the cell capacity, and offer timely warning signal once the cell is overcharged or overdischarged. The developed stretchable strain sensor possesses comprehensive advantages of low mechanical constraint, tailorable small size, easy integration and conformality to cells, and little temperature interference, which would serve as a promising candidate for future battery state analysis and safety monitoring.

Characterization of electrical conductivity and dielectric properties of electroless NiP/rGO composite coated hemp fiber with various weight% of rGO and coating duration

The present study made an attempt to develop a conductive hemp fiber (HF) through an electroless Ni-P composite coating with reduced graphene oxide (rGO) as reinforcement. Four different Ni-P/rGO coated fibers were prepared with the variations in the coating time (20/40 min) and weight percentages of rGO (5/10 %). The coated fibers were characterized using various tools like: Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM), to identify the functional groups, phase structure, and morphological changes, induced by the rGO reinforcement. The coating duration and weight percentage of rGO had influenced the dielectric properties and electrical conductivity. In comparison, the coating duration of 40 min with 10 % addition of rGO has enhanced the electrical conductivity to 13.75 % and 37.5 % respectively. Furthermore, the mechanism behind the improvement in the conductivity is detailed in this study.

Selective Cu electroplating enabled by surface patterning and enhanced conductivity of carbon fiber reinforced polymers upon air plasma etching

We demonstrate a sustainable post-processing of carbon fiber reinforced epoxy polymer (CFRP) composites by air plasma etching that permits regular electroconductive surface patterning through direct Cu galvanic metallization, in contrast to the untreated composite. Our study reveals a significant property dependence of the composite with respect to the position to the fiber/matrix composite surface and treatment. The enhancement in electrical conductivity was not compromised by the lower structural integrity of the composite, as the embedded carbon fibers remained unaffected by the air plasma etching process. The metallized Cu domains on the composite exhibit good hardness and excellent solderability potential. Thus, the electroconductive surface patterning of the composite, preceding galvanic metallization, facilitates the selective deposition of Cu layer domains. This step by step process, relying on the creation of selective electroconductive areas on the composite by plasma etching, enables galvanic metallization. Consequently, it enhances the potential for multifunctional composite applications. The feasibility of galvanic metallization brings new perspectives in selective metallization of composites by allowing the tailoring of the metal layer thickness, microstructure and selection of the metal.

Conductive and alignment-optimized porous fiber conduits with electrical stimulation for peripheral nerve regeneration

Autologous nerve transplantation (ANT) is currently considered the gold standard for treating long-distance peripheral nerve defects. However, several challenges associated with ANT, such as limited availability of donors, donor site injury, mismatched nerve diameters, and local neuroma formation, remain unresolved. To address these issues comprehensively, we have developed porous poly(lactic-co-glycolic acid) (PLGA) electrospinning fiber nerve guide conduits (NGCs) that are optimized in terms of alignment and conductive coating to facilitate peripheral nerve regeneration (PNR) under electrical stimulation (ES). The physicochemical and biological properties of aligned porous PLGA fibers and poly(3,4-ethylenedioxythiophene):polystyrene sodium sulfonate (PEDOT:PSS) coatings were characterized through assessments of electrical conductivity, surface morphology, mechanical properties, hydrophilicity, and cell proliferation. Material degradation experiments demonstrated the biocompatibility in vivo of electrospinning fiber films with conductive coatings. The conductive NGCs combined with ES effectively facilitated nerve regeneration. The designed porous aligned NGCs with conductive coatings exhibited suitable physicochemical properties and excellent biocompatibility, thereby significantly enhancing PNR when combined with ES. This combination of porous aligned NGCs with conductive coatings and ES holds great promise for applications in the field of PNR.

Core-sheath smart polymer fiber composites with high elasticity and thermal conductivity

Thermal conductive polymer fibers have broad development prospects because of its excellent thermal and mechanical properties. However, currently reported polymer fibers cannot simultaneously possess high thermal conductivity and high resilience, which greatly limits the application of thermal conductive polymer fibers. Therefore, preparing fibers with high thermal conductivity and high resilience is extremely challenging. The thermoplastic polyurethane/boron nitride liquid metal (TPU/BN-LMs) fiber with core sheath structure is prepared by coaxial wet spinning technology, the boron nitride (BN) doped in thermoplastic polyurethane elastomer (TPU) as sheath and the liquid metal (LMs) as core. The maximum tensile strength of the fiber is 3.9 MPa, and the elongation can reach 400 %. After multiple cycles of stretching, it can return to its original state. In addition, the thermal conductivity of the fiber in the horizontal direction and the vertical direction are 10.0 W m−1 K−1 and 4.6 W m−1 K−1, respectively. This work solves the current problem of high thermal conductivity and high resilience of thermally conductive polymer fibers that are difficult to be compatible. And it provides a new research idea for the design and preparation of new high thermal conductivity and high resilience polymer fiber materials.

Material Selection of Conductive Fibers for Touchable Gloves and Application of Graphene

In recent years, nanometer conductive materials are the focus of research. Graphene is widely recognized and used in recent years, they have excellent flexibility, mechanical strength and electrical conductivity, with low dimensions and large specific surface area characteristics, in the field of sensors and daily life has great application potential, perhaps some emerging nanomaterials and technologies can provide the possibility of progress for touch screen gloves. Most touchscreen gloves on the market today use metal fibers, but compared with other metals and non-metallic materials, graphene is undoubtedly a suitable and superior conductive fiber choice now and in the future.

Piezoresistive pressure sensor based on conductive MWCNTs@PANI fiber network for motion sensing and human–machine interface

AbstractWearable smart sensors have broad prospects in medical health and physical exercise. In this study, the core–shell conductive fiber membrane was prepared by adding multiwalled carbon nanotubes during polymerization of aniline on spun fibers. In comparison to the conventionally utilized polymerized aniline, the integration of carbon nanotube particulates enhances the conductivity and surface area, provides more aniline polymerization sites, and simultaneously increases the stability of the composite film. The pressure sensor has a sensitivity of 61.12, 40.32, and 23.17 kPa−1 in the range of 0–7.1 kPa, 7.1–11.1 kPa, and 11.1–19.54 kPa. In addition, it has a fast response time (loading time of 120 ms and unloading time of only 22 ms) and exhibits excellent cyclic stability through numerous loading–unloading cycles. These properties enable the sensor to be applied to real‐time monitoring of human sports health, such as knee and elbow bending, mouse clicking, beaker holding, and so on. This research method provides a new strategy and technology for conducting polymers as materials for flexible electronic equipment.

Construction of thermally conductive and insulating fibers of BN nanosheet/aramid nanofiber composites with high-temperature resistance via sol-gel wet spinning

With the intensification of global warming and the occurrence of extremely hot weather, there is an urgent need for textiles that can effectively regulate temperature. Using amino-functionalized boron nitride nanosheets (K-BNNSs) and aramid nanofibers (ANFs) as materials, the well-oriented thermally conductive insulating textile fibers with “lotus root” structure were directly prepared by sol–gel wet spinning process. The axial thermal conductivity of a single fiber can be as high as 22.4 W/(m·K), and has an excellent tensile fracture strength (176.6 MPa). Thermal infrared imaging revealed that the fibers woven into textiles had a more significant heat dissipation capacity than commercial cotton fabrics. The fiber obtained by this low-cost preparation method provides a cooling textile with excellent heat-dissipation ability and has wide application prospects in emerging textiles.

Electrical conductivities and temperature distributions of carbon fiber 3D woven composites with different electric field direction

Electrical conductivities and temperature generations are related closely for carbon fiber composites under electric fields. Here we reported the current conductivity and electro-thermal behavior of carbon fiber reinforced 3D orthogonal woven structure composites (3DOWCs) along different current directions. The influence of woven architectures and contacts on electrical and thermal behaviors was analyzed with finite element analysis (FEA) model. We found that the conductivity was the highest along warp direction and the lowest along Z-binder direction. The conductivity increased with the increase of in-plane angles. The overall conductivity of Z-binder direction was affected by weft/Z-binder yarn interface. In-plane angle directions, the warp/weft interfacial conductivity affected overall conductivities, which had the largest temperature contribution. The maximum current density and temperature of warp yarns decreased with the increase of in-plane angles. The proportion of weft yarns in current density and temperature rise increased with the increase of in-plane angles.

RGO/ANFs composite fibers with dual functions of thermal conductivity and electromagnetic shielding of lotus root structure based on sol-gel wet spinning

Textiles that exhibit electromagnetic shielding and high thermal conductivities are valuable materials. Graphene is considered the best candidate material because of its excellent thermal and electrical conductivities. However, there is a challenge that the strong interaction between the layers is easy to aggregate and affect the mechanical properties. At present, the graft modification of graphene can effectively improve its dispersion in solvents. Herein, we fabricate highly oriented composite fibers with “lotus root” structures via sol-gel wet spinning using graphene and aramid nanofiber (ANF) raw materials. The reduced graphene oxide (RGO)/ANFs composite fibers (50RGO/ANF-Ca2+-0.5) exhibit an excellent tensile fracture strength (304.05 MPa). The axial thermal conductivity of a single fiber is 30.42 W/(m·K) due to its highly oriented structure along the axis and dense three-dimensional network structure inside. Thermal infrared imaging shows that the 50RGO/ANF-Ca2+-0.5 textile has a higher surface temperature of 1.1 °C than commercial cotton fabric on human skin, and has a more significant heat dissipation capacity. The 50RGO/ANF-Ca2+-0.5 textiles exhibit electromagnetic shielding efficiencies of up to 49.8 dB. The composite fiber obtained via this low-cost preparation method endows textile with dual functions of thermal conductivity and electromagnetic shielding and has wide application prospects in emerging textiles.