Interface porosity in multilayered all‐conducting polymer electrodes

Abstract

Multilayered films made with at least two different electroactive polymers, in which the least conducting one acts as a dielectric and separates the layers made with the other, behave as efficient electrodes for electrochemical supercapacitors. In this work, we present a simple strategy to develop improved multilayered electrodes with structured interfaces by enhancing the porosity of the dielectric. This has been achieved by growing sodium chloride crystals onto a conducting polymer layer and, after generation of all required layers using the layer‐by‐layer electrodeposition technique, salt crystals have been eliminated by water etching. Results from morphological and topographical studies on single‐layered poly(3,4‐ethylenedioxythiophene) (PEDOT), poly(N‐methylpyrrole) (PNMPy), and poly(3,4‐ethylenedioxythiophene‐co‐N‐methylpyrrole) (COP), as well as electrochemical investigations on bi‐layered films with enhanced porosity at the interface between the two layers, have been used to design new four‐layered electrodes. These consist in two layers of PEDOT separated by two layers of nanosegregated COP with a porous interface in the middle. Although the properties of the new four‐layered electrodes improve due to the porous interface, the highest specific capacitance corresponds to the two‐layered electrode in which two PEDOT layers are separated by an ultra‐porous interface. POLYM. ENG. SCI., 59:1624–1635 2019. © 2019 Society of Plastics Engineers

High performance optical and electrical properties of zinc oxide reinforced poly(diphenylamine) nanocomposites for optoelectronic applications

“…[1][2][3][4] The enhanced properties are related to the strong synergistic interaction between the constituent components and the conductive network formed by the fillers within the polymer matrix. [5,6] Polymer nanocomposite combines the features of its constituents, such as durability, processability, electrical and optical properties. [2,7] Inorganic nanofillers, including transition metal oxide nanoparticles, distinguish themselves from conventional reinforcing fillers in polymers because of their mixed valence properties.…”

Porous Poly(3,4‐ethylenedioxythiophene)‐Based Electrodes for Detecting Stress Biomarkers in Artificial Urine and Sweat

“…The design of advanced components for biosensors to measure stress‐indicative biomarkers in a noninvasive, cost‐effective, and rapid approach would greatly benefit the field of healthcare technology. With this aim in mind, PEDOT/COP/p/COP/PEDOT electrodes, which were prepared following an already optimized protocol, [ 33 ] have been applied to quantify stress biomarkers. In this four‐layered system, two layers of PEDOT are separated by two layers of nanosegregated COP with a porous interface in the middle ( Scheme ).…”

“…[28] For COP/p films, the growth and elimination of NaCl crystals induced an increase of the surface porosity in comparison to pristine films, which is ascribed to the stress exerted by the growing inorganic crystals in the already open polymer network of EDOT-rich phases. [33] Hence, throughout the process of introducing interface porosity, EDOT-rich phases behaved as an adaptive surface that accommodated the crystals. Consequently, once the NaCl crystals were dissolved, EDOT-rich phases appeared much more porous than NMPy-rich phases, which remained more compact.…”

“…Such arrangement promotes the synergy between the CPs at the interfaces, thus enhancing their electrochemical properties and increasing their ability to store charge in comparison to the individual CP. [ 33 ] Indeed, the key feature of this system is the presence of an ultra‐porous nanostructured interface in the middle of the dielectric (i.e., PEDOT/COP/p/COP/PEDOT, where p refers to porous). Such interface porosity, obtained by growing NaCl crystals and then eliminating them with water etching, causes structural distortions in the polymer network that, in conjunction with the phase‐segregated structure of COP, improved its supercapacitor response.…”

“…Such interface porosity, obtained by growing NaCl crystals and then eliminating them with water etching, causes structural distortions in the polymer network that, in conjunction with the phase‐segregated structure of COP, improved its supercapacitor response. [ 33 ] Hence, in order to exploit such enhanced performance, the four‐layered all‐conducting polymer system has been applied as the main component in a sensing device to monitor stress biomarkers levels (DA and/or 5‐HT) in phosphate‐buffered saline (PBS), as well as in simulated body fluids, i.e., artificial urine and sweat. For the sake of comparison, sensors with an intermediate region made of PNMPy were also investigated (i.e., PEDOT/PNMPy/p/PNMPy/PEDOT).…”