Electroconductive Fibers Research Articles

Fabric‐Based TENG Woven with Bio‐Fabricated Superhydrophobic Bacterial Cellulose Fiber for Energy Harvesting and Motion Detection

AbstractFabric‐based triboelectric nanogenerators (TENGs) exhibit superior output performance, flexibility, and wearability. However, the fabric structure often creates gaps that accumulate contaminants, which weaken the performance and durability of the TENGs. To address this challenge, a novel eco‐friendly superhydrophobic fabric‐based TENG (SF‐TENG) woven with superhydrophobic electroconductive bacterial cellulose fiber (SEBC fiber) is presented. To construct durable superhydrophobicity, an ingenious bio‐fabricated method is employed for the shell–core structure. SEBC fibers with bio‐fabricated shell–core structure exhibit excellent electroconductibility, mechanical property, biodegradability, and durable superhydrophobicity. SF‐TENG displays a maximum open‐circuit voltage of 266.0 V, a short‐circuit current of 5.9 µA, and an output power of 489.7 µW, and successfully powers devices such as stopwatch and calculator. Abilities of self‐cleaning and anti‐fouling guarantee the stable output performance of SF‐TENG under harsh environmental conditions such as liquids pouring. Furthermore, the intelligent clothing is designed based on SF‐TENG to detect motion signals, and it is further utilized to construct a Sports and Health Monitoring System as a deep application. In summary, this study provides a novel strategy of bio‐fabrication for the design and preparation of superhydrophobic electroconductive fiber with shell–core structure. The SF‐TENG demonstrates practicability, stability and is promising for wearable devices in harsh environmental conditions.

Electrospun electroconductive constructs of aligned fibers for cardiac tissue engineering

Myocardial infarction remains the leading cause of death in the western world. Since the heart has limited regenerative capabilities, several cardiac tissue engineering (CTE) strategies have been proposed to repair the damaged myocardium. A novel electrospun construct with aligned and electroconductive fibers combining gelatin, poly(lactic-co-glycolic) acid and polypyrrole that may serve as a cardiac patch is presented. Constructs were characterized for fiber alignment, surface wettability, shrinkage and swelling behavior, porosity, degradation rate, mechanical properties, and electrical properties. Cell-biomaterial interactions were studied using three different types of cells, Neonatal Rat Ventricular Myocytes (NRVM), human lung fibroblasts (MRC-5) and induced pluripotent stem cells (iPSCs). All cell types showed good viability and unique organization on construct surfaces depending on their phenotype. Finally, we assessed the maturation status of NRVMs after 14 days by confocal images and qRT-PCR. Overall evidence supports a proof-of-concept that this novel biomaterial construct could be a good candidate patch for CTE applications.

Surface engineering via self-assembly on PEDOT: PSS fibers: Biomimetic fluff-like morphology and sensing application

Wearable sensors based on fibers or textiles are attracting widespread attention due to their potential applications in wearable health monitoring and care systems, where high sensitivity plays an essential role in the development of electroconductive fibers. Though the great progress has been made in designing novel structures and understanding sensing mechanism, how to prepare conductive fibers with high sustainability and conductivity via a facile and efficient method is still a challenge. Herein, inspired by the spider’s fluff, an ion-induced self-assembly is proposed and performed to obtain continuous and large-scale fabrication of poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) fibers with an array microstructure. The formation of copper complex with fluff-like shape occurs spontaneously on the surface of PEDOT fibers without any additional post-treatment or harsh condition, which is difficult to achieve by other approaches. Benefiting from the fluff-like array, these biomimetic PEDOT: PSS-Cu2+ fibers possess a near 5-fold increase in specific surface area compared to that of pristine PEDOT: PSS fibers, which endows it with a good pressure sensitivity with ultralow detection limit (~82 Pa) and fast response time (47 ms). We further demonstrate their potential applications for airflow detection, real-time information transmission, and gravity/pressure sensing while decorating such biomimetic fibers to braided fabrics. More importantly, this work sheds light on the formation mechanisms of microstructures on the fiber, inspiring a unique path for conventional wet-spinning technology and novel fiber-surface design in order to achieve its outstanding sensitivity.

폴리에틸렌이민 전처리와 황화구리 무전해 도금에 의한 전기전도성 면섬유의 제조

면섬유에 폴리에틸렌이민(PEI)을 처리하여 양이온화시키고, 이를 황산구리와 티오황산나트륨 혼합 용액으로 황화구리 무전해 도금함으로써 전기전도성 면섬유를 제조하였다. PEI 전처리 및 황화구리 도금에 따른 시료들의 표면저항, 마찰대전압, 전자파 차폐효율 변화 등을 분석하였다. 면섬유에 대한 PEI 전처리는 0.5% 이하의 낮은 농도로도 충분하였으며, PEI 전처리된 면직물에 4% 황화구리와 4% 티오황산나트륨 혼합 용액으로 80 °C에서 2시간 동안 황화구리 도금시키면 표면저항이 1~2 Ω/sq 이하인 우수한 전기전도성을 나타내었다. 0.1% PEI 용액으로 전처리한 후 황화구리로 무전해 도금함으로써 0.01 MHz~3 GHz의 주파수 대역에서 35~40 dB의 우수한 전자파 차폐효율을 갖는 전기전도성 면직물을 제조할 수 있었다.

Bioinspired Superelastic Electroconductive Fiber for Wearable Electronics.

Electroconductive fibers (E-fibers) with excellent flexibility and elasticity are crucial for the advancement of smart textiles for wearable electronics. However, the current metal-based conductive wires are not capable of satisfying the practical demands attributing to their limited stretchability and inferior antiabrasion ability. Herein, we report a superelastic and electroconductive fiber with a spring-like structure, inspired by the unique coiled tendril structures of climbing plants. The E-fiber is constructed by wrapping a flexible yet conductive carbon nanotube/polydimethylsiloxane (CNT/PDMS) composite yarn onto a polyester filament. In this system, the polyester filament provides mechanical robustness and stretchability, while the coiled CNT/PDMS composite yarn (C/P CY) offers sufficient conductivity. Notably, the as-fabricated E-fiber possesses high stretchability (165%), exceptional tensile force (660 cN), extraordinary antiabrasion ability, and remarkable electrical stability under various deformations. In addition, the great air permeability and electrothermal stability are also achieved, which are essential for comfortable wear and steady conduction. The developed E-fiber based on CNT composite wrapping yarn, together with its exceptional mechanical and electrical performance, provides the material with promising prospects for practical applications in wearable electronics.

Preparation of graphene-coated conductive fibers by layer-by-layer assembly of negative and positive charged graphene oxide

Abstract Graphene recently gained extensive interests in electroconductive fibers because of its excellent electrical conductivity. Generally, graphene coated conductive fibers are fabricated in two steps, first graphene oxide (GO) dip-coated to the surface of the fiber, then GO reduced to reduced graphene oxide (RGO). To enhance the conductivity of the above fiber, the mass of graphene on the fiber surface is increased by repeated dip-coating of GO or alternating coating of GO and adhesive layer. The former method results in a low adsorption efficiency due to the electrostatic repulsion of graphene oxide. In the latter method, the adhesive layer is generally non-conductive, which reduces the electrical conductivity of the fiber. Thus we propose a novel method to prepare graphene coated conductive fibers by layer by layer assembly of the negative and positive charged GO dispersion here. In this study, the charge of GO was reversed to positive with AlCl3. Polyacrylonitrile (PAN) fiber was coated with Bovine serum albumin (BSA) to pretreat its surface. The pretreated PAN was then alternately dip-coated in the negative and positive GO dispersion. Finally, GO was reduced to graphene by the HI reagent. The prepared PAN conductive fiber has a resistivity of 38.5 Ω·cm, which is reduced by 7 orders of magnitude compared with the resistivity of the original PAN fiber. Moreover, the conductivity of graphene-coated fiber is maintained at around 92% after 10 washing treatments, demonstrating a better durability.

아크릴 도전사와 폴리프로필렌 섬유로 된 혼섬 슬라이버를 사용한 전자파 차폐용 복합재료의 새로운 제조 방법

아크릴 도전사와 폴리프로필렌 섬유로 된 혼섬 슬라이버를 사용한 전자파 차폐용 복합재료의 새로운 제조 방법

Vibration electrospinning of Polyamide-66/Multiwall Carbon Nanotube Nanocomposite: introducing electrically conductive, ultraviolet blocking and antibacterial properties

Abstract Fabrication of electro-conductive fiber is a novel process. Nanocomposites of multiwall carbon nanotube/polyamide66 were produced by electrospinning with different amounts of multiwall carbon nanotube. Field emission scanning electron microscope and Fourier transform infrared spectroscopy of samples proved the existence of multiwall carbon nanotube distribution in polyamide 66 nanofibers. Results showed that electro conductivity of electrospun multiwall carbon nanotube/polyamide 66 nano fiber has increased in comparison with electrospun polyamide 66. Moreover, UV blocking of samples was investigated which has shown that using multiwall carbon nanotube in polyamide 66 increases UV blocking of fibers. Furthermore, anti-bacterial activity of nanocomposite showed that these nanocomposites have antibacterial property against both Staphylococcus Aureus and Escherichia Coli bacteria according to AATCC test method.

Evaluation of the walking performance between 3D-printed and traditional fabricated ankle-foot orthoses— A prospective study

The research results that constitute the technological basis for production of polyethylene terephthalate fibers with novel consumer properties demanded by the textile industry were presented in the preceding chapters. Complex study of potential opportunities of the crazing technology has established the limits of effective industrial application of the crazing. An array of tasks which solution through the use of the crazing technology is insufficiently effective at fibers possessing has been defined. However, we believe this is a valuable experience for specialists of applied materials science and processors of fibers as an incentive for improvement of the crazing technology. The results of the research on possibility to form the radioabsorbing and electroconductive fibers, as well as the results of experiments on the crazing modification of bicomponent and ultrathin fibers, are presented in this chapter.

Carbon Fibre Filled Radiation Absorbing Nonwovens

The dependence of electromagnetic radiation reflection coefficient of nonwovens on the content in them of carbon fibres cut to various lengths is studied. A technique for inserting electroconductive carbon fibres, which ensures formation of an intermediate layer of these fibres between fabrics from dielectric fibres, is described. The frequency dependence of the reflection coefficient on the intermediate layer composition and carbon fibre cut length for fabrics and multilayered materials obtained by joining fabrics is determined. It is shown that the multilayered materials are of interferential-absorptive type, but are also capable of absorbing low-frequency electromagnetic radiation.

Electro-conductive Palmyra Fibers By In Situ Polymerization of Pyrrole

ABSTRACTPalmyra (Borassus flabellifer L.) is one of the natural fruit fibers that are available in plenty. This fiber has many advantages, such as biodegradability, renewability, low density, and low cost, which offer greater opportunities to develop new applications. Imparting electrical conductivity to this fiber may open up avenues for various novel applications. In the present study, Palmyra fibers are made electro-conductive by in situ chemical polymerization of pyrrole with FeCl3 oxidant and PTSA dopant. Prepared electro-conductive fibers show average electrical resistivity 2.96 kΩ cm−1. A positive correlation is found between fiber-length and electrical resistance, whereas a negative correlation is found in between fiber-diameter and electrical resistance. FTIR study is conducted to understand the chemical interaction between lingo-cellulose and polypyrrole. Tensile properties and thermal degradation behavior of the prepared electro-conductive fibers are evaluated, and significant deterioration of both tensile properties and thermal stability is observed. Due to this reason, these electro-conductive fibers are unsuitable for mechanical processing and high-tech applications. But the response of these fibers in different pH solution is investigated, and their possible application as a pH sensor has been explored.

Water-triggered macroscopic structural transformation of a metal–organic framework

A millimeter-long metal–organic framework fiber has been successfully constructed. The fiber structure was unexpectedly found via the solvent vaporization process of a dispersion of a Zn-based MOF crystal. Detailed experiments and structural analysis indicate that a humid environment is a key to the growth of the fiber structure, inducing drastic transformation of the MOF crystal morphology from the nanoscopic to macroscopic scale. Synchrotron X-ray single-crystal diffraction analysis reveals that the complete crystal transformation from the Zn-MOF sheet to Zn-MOF fiber is accompanied by water coordination and ligand rearrangement. The highly anisotropic MOF fiber is easily converted to an electro-conductive fiber while maintaining the long-fiber morphology.

Novel Carbon Nanotube/Cellulose Composite Fibers As Multifunctional Materials.

Electroconductive fibers composed of cellulose and carbon nanotubes (CNTs) were spun using aqueous alkaline/urea solution. The microstructure and physical properties of the resulting fibers were investigated by scanning electron microscopy, Raman microscopy, wide-angle X-ray diffraction, tensile tests, and electrical resistance measurements. We found that these flexible composite fibers have sufficient mechanical properties and good electrical conductivity, with volume resistivities in the range of about 230-1 Ohm cm for 2-8 wt % CNT loading. The multifunctional sensing behavior of these fibers to tensile strain, temperature, environmental humidity, and liquid water was investigated comprehensively. The results show that these novel CNT/cellulose composite fibers have impressive multifunctional sensing abilities and are promising to be used as wearable electronics and for the design of various smart materials.

Thermoplastic Composites Reinforced with Textile Grids: Development of a Manufacturing Chain and Experimental Characterisation

A significant improvement in the properties of plastic components can be achieved by introducing flexible multiaxial textile grids as reinforcement. This reinforcing concept is based on the layerwise bonding of biaxially or multiaxially oriented, completely stretched filaments of high-performance fibers, e.g. glass or carbon, and thermoplastic components, using modified warp knitting techniques. Such pre-consolidated grid-like textiles are particularly suitable for use in injection moulding, since the grid geometry is very robust with respect to flow pressure and temperature on the one hand and possesses an adjustable spacing to enable a complete filling of the mould cavity on the other hand. The development of pre-consolidated textile grids and their further processing into composites form the basis for providing tailored parts with a large number of additional integrated functions like fibrous sensors or electroconductive fibres. Composites reinforced in that way allow new product groups for promising lightweight structures to be opened up in future. The article describes the manufacturing process of this new composite class and their variability regarding reinforcement and function integration. An experimentally based study of the mechanical properties is performed. For this purpose, quasi-static and highly dynamic tensile tests have been carried out as well as impact penetration experiments. The reinforcing potential of the multiaxial grids is demonstrated by means of evaluating drop tower experiments on automotive components. It has been shown that the load-adapted reinforcement enables a significant local or global improvement of the properties of plastic components depending on industrial requirements.

Development and Risk Assessment of Electro-Conductive Fiber "CNTEC" by Carbon Nano-Tubes Coating

Development and Risk Assessment of Electro-Conductive Fiber "CNTEC" by Carbon Nano-Tubes Coating

Composite materials for building heated coverings of roads and runways of airdromes

The paper is dedicated to the development of new compositions of electroconductive concretes reinforced with chemical electroconductive fibers. The compositions are designed for building heated coverings of roads and runways of airdromes. A classification of electroconductive concretes is given, and the results of comparative experimental investigations of the compositions developed are presented.

Inductive fiber-meshed strain and displacement transducers for respiratory measuring systems and motion capturing systems

Unobtrusive transducers play an important part in wearable and mobile computing fields. One out of many methods of implementations is to use smart materials and integrate them into intelligent structures via the route of fabric manufacturing processes that are capable of transducer action. This new breed of transducers is called fabric transducers. However, fabric transducers that were developed mainly focused on the variations in the resistance and capacitance of the electroconductive fabric structures. Therefore, they inhibit the disadvantages that are common in resistive and capacitive transducers. Moreover, they have limitations in operating as strain or displacement transducers. To overcome the limitations, research has been carried out to investigate constructions of an inductive fiber meshed strain and of displacement transducer. Electroconductive fibers (polymeric and metallic) of different conductivity levels were arranged in helical paths to form coils. The fibers were arranged by using flat bed-knitting technology. This paper discusses the constructions, simulations, performances, and limitations of the inductive fiber meshed transducers. Also, the discussion is further extended toward two specific applications: respiratory measuring systems and motion capturing systems

Dependence of Electrical Conductivities of Acetylene Black Filled Nylon-12 Fibers on Draw Spinning Conditions

Draw spinning conditions for acetylene black (AB) filled nylon-12 fibers were studied to get electro-conductive fibers with well-developed conduction routes of AB. A draw ratio and a draw temperature were varied to see their influence on the electro-conductivity of the fibers obtained. AB agglomerates tend to align along fiber axes with an increase of the draw ratio and conduction routes are developed to lower average volume resistivity (AVR), when the draw ratio is low. However, the conduction routes seem to be partially destroyed on a further increase of the draw ratio beyond 1.3. Variation of the scattering range of volume resistivity (VR) depending on the draw ratio is rather complicated, but its lowest value was obtained at the draw ratio of 1.3. As the draw temperature is raised, homogeneity of the conduction routes increases, since matrix polymers soften. However, fibers adhere to a draw role on drawing at a higher temperature than 80deg. Thus drawing with the draw ratio of 1.3 at 80deg forms fibers with the lowest AVR and the narrowest scattering range of VR. The VR of the fibers obtained under the condition remained almost unchanged regardless of the drastic change of relative humidity of the surroundings where they were placed, which indicates that they have stable electrical conductivities.

Dependence of Electrical Conductivities of Carbon Black Filled Nylon-12 Fibers on Spinning Conditions

Spinning conditions for undrawn carbon black (CB) filled nylon 12 (Ny12) fibers were studied to get electro-conductive fibers with well developed conduction routes of CB. The electrical conductivities of such fibers are assumed to be excellent and less dependent on the circumstance where they are used. Spinning was carried out using a spinneret equipped with a cooling chamber or a heating chamber. Acetylene black (AB) was employed as CB. The average volume resistivity (resistivity) for the fibers tended to decrease with increasing winding speed of the fibers irrespective of the chamber used. The orientation of Ny12 along the fiber axis is considered to be responsible for the lowering of the resistivity. This is because the former increased with increase of the winding speed and it is reasonably assumed that the conduction routes by AB are developed along the fiber axis with the orientation of the matrix polymer. Higher degrees of orientation were achieved for the fibers obtained using the cooling chamber than those using the heating chamber, when the winding speed was kept constant. However, the former had higher resistivity than the latter, when they are compared for the fibers with a same degree of orientation. This was attributed to the variation of a degree of crystallinity. Based on these results, the fibers with AB conduction routes developed effectively and accordingly with lower resistivity could be prepared by choosing proper spinning conditions. The resistivity of the fibers thus obtained remained almost unchanged regardless of the drastic change of relative humidity of the circumstance where they were put, which indicates that they have stable electrical conductivities.

The Critical Conductivity of Electro-Condutive Fibers to Obtain a Good Antistatic Pereformance

It is well known that there may be a critical conductivity which gives a good antistatic performance to electro-conductive fibers (ECF). However. in the past, this critical point was not clear because there was no accurate evaluation system to measure the antistatic properties. The authors recently developed a new measuring apparatus, (KB-system), which has excellent accuracy and reliability for evaluating the anti-static performance of fabrics. By using the KB system, the critical point has been determined to be 1×109Ω•cm for both carbon black-applied ECF and metallic oxide (semiconductor)-applied ECF. This value is one hundred times greater than that of antistatic fibers prepared by using antistatic agents. The results show the existence of essential difference in discharging mechanisms for ECF and antistatic fibers.