Search

Abstract: A simple and scalable method to fabricate a yarn‐type supercapacitor with a large specific capacitance without the aid of traditional pseudocapacitive electrode materials such as conducting polymers and metal oxides is reported. The yarn‐type supercapacitors are made from twisting reduced graphene oxide (rGO) or/and single‐walled carbon nanotubes (SWNTs)‐coated Korean traditional paper (KTP). The yarn‐type paper supercapacitor displays surprisingly enhanced electrochemical capacitance values, showing synergistic effect between rGO and SWNTs (500 times larger than performance of yarn‐type rGO‐coated paper supercapacitors). Coating rGO or/and SWNTs on KTP gives good morphology to the composite film, in which porosity increases and mean pore diameter decreases. The yarn‐type rGO/SWNT paper supercapacitor shows good mechanical strength, high flexibility, excellent electrochemical performance, and long‐life operation. The yarn‐type supercapacitor has an excellent electrochemical performance with a specific capacitance of 366 F g−1 at scan rate of 25 mV s−1 and high stability without any degradation in electrical performance up to 10 000 charge–discharge cycles. The average capacitance of rGO/SWNT@KTP yarn‐type supercapacitors is seven times higher than that of sheet‐type supercapacitors at scan rate of 500 mV s−1. The lighting of a red light‐emitting diode (LED) is demonstrated by the yarn‐type paper supercapacitor without connecting supercapacitors in series. [ABSTRACT FROM AUTHOR]

ABSTRACT: Conventional cellulosic paper, rendered electro‐conductive, may hold considerable promise for diversified applications in such areas as electro‐magnetic interference shielding and energy storage. Here, an electro‐conductive cellulosic paper was prepared by surface application of multi‐walled carbon nanotubes (MWCNTs)/polyaniline (PANI) nanocomposites onto a conventional base paper. MWCNTs/PANI nanocomposites were prepared by in situ polymerization of aniline with different contents of MWCNTs and used as electro‐conductive filler for the fabrication of electro‐conductive surface‐coated paper. The achieved MWCNTs/PANI nanocomposites exhibited a core‐shell structure, as evidenced by TEM. Effects of feeding ratios of MWCNTs on the rheological behavior of nanocomposite coatings, as well as the mechanical properties and electrical conductivity of surface‐coated paper were studied. Results revealed that the rheological behavior of the nanocomposite coatings showed strong dependence on the MWCNTs content. Moreover, both the electro‐conductivity and mechanical properties of surface‐coated paper were improved as a function of surface application of MWCNTs/PANI nanocomposites, particularly, in presence of an optimum content of MWCNTs. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46329. [ABSTRACT FROM AUTHOR]

This paper describes the design and fabrication of electrically controlled paper actuators that operate based on the dimensional changes that occur in paper when the moisture absorbed on the surface of the cellulose fibers changes. These actuators are called 'Hygroexpansive Electrothermal Paper Actuators' (HEPAs). The actuators are made from paper, conducting polymer, and adhesive tape. They are lightweight, inexpensive, and can be fabricated using simple printing techniques. The central element of the HEPAs is a porous conducting path (used to provide electrothermal heating) that changes the moisture content of the paper and causes actuation. This conducting path is made by embedding a conducting polymer (PEDOT:PSS) within the paper, and thus making a paper/polymer composite that retains the porosity and hydrophilicity of paper. Different types of HEPAs (straight, precurved, and creased) achieved different types of motions (e.g., bending motion, accordion type motion). A theoretical model for their behavior is proposed. These actuators have been used for the manipulation of liquids and for the fabrication of an optical shutter. [ABSTRACT FROM AUTHOR]

Conducting polymers have been considered for use as cathode materials in rechargeable lithium-ion batteries (LIBs) since 1981 but problems with poor cycling stability, rapid self-discharge, and low energy and power densities have so far limited their applicability. Herein it is shown that nanostructured freestanding conducting polymer composites [e.g., polypyrrole (PPy) and polyaniline (PANI)] can be used to circumvent these shortcomings. Freestanding and binder-free PPy and cellulose-based composites can straightforwardly be used as versatile organic cathode materials for LIBs. The composite, reinforced with chopped carbon filaments (CCFs), exhibited a large active mass loading of approximately 10 mg cm−2, an areal capacity of 1.0 mAh cm−2 (corresponding to 102 mAh g−1), and stable cycling. With an active mass loading of 4.4 mg cm−2, a capacity of 0.22 mAh cm−2 (corresponding to 58 mAh g−1) was found for current densities of 5 A g−1 yielding discharge times of approximately 40 seconds, and a capacity retention of 91 % over 100 cycles was obtained at 0.2 A g−1. The present method constitutes a straightforward approach for the manufacturing of high-performance freestanding electroactive conducting-polymer-based paper-like electrodes for use in inexpensive and sustainable, high-performance organic LIBs. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel strategy via paper as an effective substrate has been introduced as a thermoelectric material in this work. Free-standing poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/paper composite films are conveniently prepared by a one-step method of directly writing PEDOT:PSS solution on paper, making the process simple, rapid, and facile. The free-standing composite films display excellent flexibility, light weight, soaking stability in water, and great potential in large-scale production. Improved thermoelectric properties are obtained in PEDOT:PSS/paper composite films, owing to the simultaneously enhanced Seebeck coefficient (30.6 μV K−1) and electrical conductivity, and a low thermal conductivity (0.16 W m−1 K−1) compared with pristine PEDOT:PSS films. The results indicate that paper as an effective substrate is suitable for the preparation of high-performance and flexible thermoelectric materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 737-742 [ABSTRACT FROM AUTHOR]

We proposed and experimentally demonstrated a cost-efficient and easy-to-fabricate flexible thin-film nanocrystal quantum dot (NCQD) photodetector, by sandwiching a piece of NCQD-soaked tracing paper between two PEDOT:PSS electrodes. The highly conductive and transparent multilayer polymer electrodes are printed with an office inkjet printer without further patterning on commercial unmodified transparency films. The tracing paper is able to act as both the bed for NCQD attachment and the interspacing layer to prevent short-circuiting in vertical devices. Consistent increase in device performance is observed when the bending radius becomes smaller. Linear I-V characteristics are obtained, which show our device structure works as a photoconductor. [ABSTRACT FROM PUBLISHER]

Conductive polymers have been studied extensively because of their attractive physical properties, such as conductivity, luminescent performance, and dielectric property. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most employed conductive polymers for applications, such as a buffer layer of organic electroluminescent devices, due to its high conductivity and electrical stability. In this study, we fabricated a conductive paper coated with PEDOT by direct polymerization onto a paper sheet. The conductive paper exhibited the electrical conductivity of 1.8 S/cm. Scanning electron microscopy images of the conductive paper showed two structures: thin polymer membranes attached to cellulose fibers at the surfaces, and thick polymer sheets extended through the void spaces between the fibers in the inner layers. Consequently, strong interactions between the PEDOT and the cellulose fibers enhanced mechanical properties of the conductive paper. Electron probe X-ray microanalysis (EPMA) revealed distribution elemental maps of carbon, oxygen, sulfur, chlorine, and iron on the conductive paper. [ABSTRACT FROM AUTHOR]

Uniform, ultra‐thin, and conformal films of conducting polymers can be readily fabricated directly onto large‐area substrates by oxidative chemical vapor deposition (oCVD). Since oCVD avoids high substrate temperatures and the use of solvents, no transfer step is required for integrating oCVD films into devices, even when employing paper and textile substrates. More details can be found in article number 1801564 by Meysam Heydari Gharahcheshmeh and Karen K. Gleason. Photo‐illustration by Felice C. Frankel. [ABSTRACT FROM AUTHOR]