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Conductive elastic fabrics are desirable in wearable electronics and related applications. Highly elastic conductive polyamide/lycra knitted fabric was prepared using intrinsically conductive polymer poly (3,4-ethylenedioxythiophene) (PEDOT) blended with polyelectrolyte poly (styrene sulfonate) (PSS) using easily scalable coating and immersion methods. The effects of these two methods of treatments on uniformity, electromechanical property, stretchability, and durability were investigated. Different grades of waterborne polyurethanes (PU) were employed in different concentrations to improve the coating and adhesion of the PEDOT:PSS on the fabric. The immersion method gave better uniform treatment, high conductivity, and durability against stretching and cyclic tension than the coating process. The surface resistance increased from ~ 1.7 and ~ 6.4 Ω/square at 0% PU to ~ 3.7 and ~ 12.6 Ω/square at 50% PU for immersion and coating methods, respectively. The treatment methods as well as the acidic PEDOT:PSS did not affect the mechanical properties of the fabric and the fabric showed high strain at break of ~ 650% and remained conductive until break. Finally, to assess the practical applicability of the treated fabric for wearable e-textiles, the change in surface resistance was assessed by cyclically stretching 10 times at 100% strain and washing in a domestic laundry for 10 cycles. The resistance increased only by a small amount when samples were stretched cyclically at 100% strain, and the samples showed good durability against washing. [ABSTRACT FROM AUTHOR]

Thermoelectric plastics are a class of polymer-based materials that combine the ability to directly convert heat to electricity, and vice versa, with ease of processing. Potential applications include waste heat recovery, spot cooling and miniature power sources for autonomous electronics. Recent progress has led to surging interest in organic thermoelectrics. This tutorial review discusses the current trends in the field with regard to the four main building blocks of thermoelectric plastics: (1) organic semiconductors and in particular conjugated polymers, (2) dopants and counterions, (3) insulating polymers, and (4) conductive fillers. The design and synthesis of conjugated polymers that promise to show good thermoelectric properties are explored, followed by an overview of relevant structure–property relationships. Doping of conjugated polymers is discussed and its interplay with processing as well as structure formation is elucidated. The use of insulating polymers as binders or matrices is proposed, which permit the adjustment of the rheological and mechanical properties of a thermoelectric plastic. Then, nanocomposites of conductive fillers such as carbon nanotubes, graphene and inorganic nanowires in a polymer matrix are introduced. A case study examines poly(3,4-ethylenedioxythiophene) (PEDOT) based materials, which up to now have shown the most promising thermoelectric performance. Finally, a discussion of the advantages provided by bulk architectures e.g. for wearable applications highlights the unique advantages that thermoelectric plastics promise to offer. [ABSTRACT FROM AUTHOR]

The continuous and long-term measurement and monitoring of physiological signals such as electrocardiography (ECG) are very important for the early detection and treatment of heart disorders at an early stage prior to a serious condition occurring. The increasing demand for the continuous monitoring of the ECG signal needs the rapid development of wearable electronic technology. During wearable ECG monitoring, the electrodes are the main components that affect the signal quality and comfort of the user. This review assesses the application of textile electrodes for ECG monitoring from the fundamentals to the latest developments and prospects for their future fate. The fabrication techniques of textile electrodes and their performance in terms of skin–electrode contact impedance, motion artifacts and signal quality are also reviewed and discussed. Textile electrodes can be fabricated by integrating thin metal fiber during the manufacturing stage of textile products or by coating textiles with conductive materials like metal inks, carbon materials, or conductive polymers. The review also discusses how textile electrodes for ECG function via direct skin contact or via a non-contact capacitive coupling. Finally, the current intensive and promising research towards finding textile-based ECG electrodes with better comfort and signal quality in the fields of textile, material, medical and electrical engineering are presented as a perspective. [ABSTRACT FROM AUTHOR]

The conductive polymer complex poly (3,4-ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) is the most explored conductive polymer for conductive textiles applications. Since PEDOT:PSS is readily available in water dispersion form, it is convenient for roll-to-roll processing which is compatible with the current textile processing applications. In this work, we have made a comprehensive review on the PEDOT:PSS-based conductive textiles, methods of application onto textiles and their applications. The conductivity of PEDOT:PSS can be enhanced by several orders of magnitude using processing agents. However, neat PEDOT:PSS lacks flexibility and strechability for wearable electronics applications. One way to improve the mechanical flexibility of conductive polymers is making a composite with commodity polymers such as polyurethane which have high flexibility and stretchability. The conductive polymer composites also increase attachment of the conductive polymer to the textile, thereby increasing durability to washing and mechanical actions. Pure PEDOT:PSS conductive fibers have been produced by solution spinning or electrospinning methods. Application of PEDOT:PSS can be carried out by polymerization of the monomer on the fabric, coating/dyeing and printing methods. PEDOT:PSS-based conductive textiles have been used for the development of sensors, actuators, antenna, interconnections, energy harvesting, and storage devices. In this review, the application methods of PEDOT:SS-based conductive polymers in/on to a textile substrate structure and their application thereof are discussed. [ABSTRACT FROM AUTHOR]

Leather is a natural material, made of collagen fiber bundles used to produce diverse types of products such as gloves and shoes due to durability, viscoelasticity, and strength. However, there is a limitation to using it for smart products due to electrical insulator properties and it needs conductivity properties to use for smart products. This study showed the new method of increasing the conductivity of goat glove leather by using poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), dimethyl sulfoxide (DMSO) as an enhancement reaction during the retanning process after leather acid dyeing. Analyze the properties of experimentally and conventionally treated leathers such as Fourier-transform infrared spectroscopy, tensile strength, color fastness, water absorption test, organoleptic, and electron microscopic analysis. The current study found that the treated leathers with 0.5 M PEDOT:PSS, 0.3 M DMSO, and acid dyestuff shows a maximum conductivity of 8.0 S/cm and can be used for making conductive gloves for operating touch-screen devices. Generally, it was found that acid-dyed leather samples treated by PEDOT:PSS with DMSO are more highly conductive than basic dyes and conductive polymers, which are applied on resining finishing. The study also found that experimented with conductive polymer leather processing has 38.4 kg/mm, 257.2% elongation, and 36.4 N tear strength, which are better than conventionally treated leather. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fundamental materials science of conducting polymers. [•] Materials engineering of conducting polymer thin films. [•] Application of organic transparent electrodes based on conducting polymers in display devices. [ABSTRACT FROM AUTHOR]

Long-term electrocardiography (ECG) monitoring is very essential for the early detection and treatment of cardiovascular disorders. However, commercially used silver/silver chloride (Ag/AgCl) electrodes have drawbacks, and these become more obvious during long-term signal monitoring, making them inconvenient for this use. In this study, we developed silver printed textile electrodes from knitted cotton and polyester fabric for ECG monitoring. The surface resistance of printed electrodes was 1.64 Ω/sq for cotton and 1.78 Ω/sq for polyester electrodes. The ECG detection performance of the electrodes was studied by placing three electrodes around the wrist where the electrodes were embedded on an elastic strap with Velcro. The ECG signals collected using textile electrodes had a comparable waveform to those acquired using standard Ag/AgCl electrodes with a signal to noise ratio (SNR) of 33.10, 30.17, and 33.52 dB for signals collected from cotton, polyester, and Ag/AgCl electrodes, respectively. The signal quality increased as the tightness of the elastic strap increased. Signals acquired at 15 mmHg pressure level with the textile electrodes provided a similar quality to those acquired using standard electrodes. Interestingly, the textile electrodes gave acceptable signal quality even after ten washing cycles. [ABSTRACT FROM AUTHOR]

Abstract The conductive polymer poly(3,4-ethylenedioxythiphene):poly(styrenesulfonate) (PEDOT:PSS) is widely used in organic electronics and printed electronics due to its excellent electronic and ionic conductivity. PEDOT:PSS films exhibit anisotropic conductivities originating from the interplay of film deposition processes and chemical structure. The previous studies found that high boiling point solvent treated PEDOT:PSS exhibits an anisotropy of 3–4 orders magnitude. Even though both the in-plane and out-of-plane conductivities are important for the device performance, the out-of-plane conductivity is rarely studied due to the complexity with the experiment procedure. Cellulose-based paper or films can also exhibit anisotropic behavior due to the combination of their intrinsic fibric structure and film formation process. We have previously developed a conductive paper based on PEDOT:PSS and cellulose which could be used as the electrodes in energy storage devices. In this work we developed a novel measurement set-up for studying the anisotropy of the charge transport in such composite materials. A tool with two parallel plates mounted with spring loaded probes was constructed enabling probing both lateral and vertical directions and resistances from in-plane and out-of-plane directions to be obtained. The measurement results were then input and analyzed with a model based on a transformation method developed by Montgomery, and thus the in-plane and out-of-plane conductivities could be detangled and derived. We also investigated how the conductivity anisotropy depends on the microstructure of the cellulose template onto which the conductive polymer self-organizes. We show that there is a relatively small difference between the in-plane and out-of-plane conductivities which is attributed to the unique 3D-structure of the composites. This new knowledge gives a better understanding of the possibilities and limitations for using the material in electronic and electrochemical devices. Graphical abstract Image 1 Highlights • Developed a simple to use generic tool for measuring 3-D resistances of thick conducting self-standing films. • The in-plane and out-of-plane conductivities were deduced by a method developed by Montgomery. • Both CNF-PEDOT:PSS and pulp-PEDOT:PSS films exhibit anisotropic conductivity. • CNF-PEDOT:PSS films show thickness independent anisotropic conductivity. • Pulp-PEDOT:PSS became less anisotropic with increasing thicknesses. [ABSTRACT FROM AUTHOR]