Fabrication of dense Ce0.9Mg0.1P2O7-PmOn composites by microwave heating for application as electrolyte in intermediate-temperature fuel cells

In the present work, we report a method of fabrication of dense 10 mol% Mg²⁺-doped cerium pyrophosphate-phosphate (Ce_0.9Mg_0.1P₂O₇-P_mO_n; CMP-P) composites by microwave heat-treatment of the preformed Ce_0.9Mg_0.1P₂O₇ substrates in the presence of phosphoric acid. The composite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The microwave heating at 375 °C for 5 min resulted in the formation of dense CMP-P composites which retained most of the pyrophosphate phase. The electrical conductivity was extracted from the EIS data and for the CMP-P composite prepared by H₃PO₄ loading for 10 h and microwave heat-treatment for 5 min it was found to be >10^?2 S m^?1 in 100–250 °C range with a maximum of 0.062 S cm^?1 at 190 °C, which was significant for its application as electrolyte in intermediate temperature fuel cells.     

Synthesis and characterization of polyaniline/carbon nanotube composites

The synthesis of polyaniline (PANI) containing different carbon nanotubes (CNTs) by in situ polymerization is reported in this study. The samples were characterized by X‐ray diffraction and scanning electron microscopy. Fourier transform infrared and ultraviolet–visible spectroscopy were used to determine the change in structure of the polymer/CNT composites. Thermogravimetric analysis showed that the composites had better thermal stability than the pure PANI. Photoluminescence spectra showed a blueshift in the PANI–single‐walled nanotube (SWNT) composite. Low‐temperature (77–300 K) electrical transport properties were measured in the absence and presence of a magnetic field up to 1 T. Direct‐current conductivity exhibited a nonohmic, three‐dimensional variable range hopping mechanism. The room‐temperature magnetoconductivity of all of the investigated samples except the PANI–SWNT composite were negative; however, it was positive for the PANI–SWNT composite, and its magnitude decreased with increasing temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polyaniline–polypropylene melt‐spun fiber filaments: The collaborative effects of blending conditions and fiber draw ratios on the electrical properties of fiber filaments

A melt‐processable polyaniline complex was blended with polypropylene under different mixing conditions and melt‐spun into fiber filaments under different draw ratios. The conductivity, electrical resistance at different voltages, and morphological characteristics of the prepared fibers were investigated. The morphology of this two‐phase blend was demonstrated to have a large effect on the conductivity level and the linearity of the resistance–voltage relationship of the blend fibers. Two factors had substantial effects on the morphology and electrical properties of the fibers. They were the size of the initial dispersed conductive phase, which depended on the melt blending conditions, and the stress applied to orient this phase to a fibril‐like morphology, which was controlled by the draw ratio of the fiber. The two factors were shown to be associated with each other to maintain an appropriate balance of fibril formation and breakage and to create continuous conductive pathways. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of new anthracene‐based semiconducting polyethers

New anthracene‐based polyethers, anthracene/bisphenol A (An–BPA) and anthracene/fluorinated bisphenol A (An–BPAF), were synthesized and characterized. An–BPA and An–BPAF were fully soluble in common organic solvents and had number‐average molecular weights of 2580 and 3240, respectively. The optical properties of the polymers were investigated with ultraviolet–visible absorption and photoluminescence spectroscopy. Blue photoluminescence was observed in dilute solutions. In solid thin films, π–π interactions influenced the optical properties, and redshifted photoluminescence spectra were obtained; a green emission (504 nm) for An–BPAF and a green‐yellow emission (563 nm) for An–BPA were found. By cyclic voltammetry, the electrochemical band gap was estimated to be 2.72 and 3.05 eV for An–BPA and An–BPAF, respectively. Single‐layer diode devices of an indium tin oxide/polyether/aluminum configuration were fabricated and showed relatively low turn‐on voltages (3.5 V for An–BPA and 3.7 V for An–BPAF). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Optical,electrical and morphological properties of transparent binary doped polyaniline thin films synthesized by in situ chemical bath deposition

The development of polymeric thin films has attracted attention in the optoelectronics field due to their transparency. The aim of the research presented was to obtain transparent polyaniline thin films by easy in situ oxidative polymerization of aniline with ammonium persulfate in the presence of a binary doping agent–poly(vinyl alcohol) mixture. Poly(acrylic acid), 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid or sodium dodecylsulfate were mixed with hydrochloric acid to form the binary doping agents. Polyaniline thin films were produced during aniline polymerization on Corning glass slides immersed in the mixture in order to study their optical, electrical and morphological properties. The optical absorption coefficient and the energy band gap were evaluated by optical transmission of the films in the UV‐visible spectral region. The optical absorption coefficient of all polyaniline films was of the order of 10⁴ cm^?1 with a maximum transmittance up to 80% at 550 nm. In order to investigate the effect of the mixture on the surface morphology and roughness of the films, atomic force microscopy was used. In general, surface roughness was reduced threefold by adding a mixture and optical transmission was increased by 20–30% without significantly affecting the absorption coefficient and the band gap of polyaniline. Islands and needle‐like structures on the film surfaces were obtained from various mixtures affecting the conductivity; for example, 0.17 S cm^?1 was obtained from needle‐like morphology, while 1.9 × 10^?4 S cm^?1 was obtained from island morphology. Raman spectroscopy studies confirmed the presence of poly(vinyl alcohol) in the thin films. Copyright © 2011 Society of Chemical Industry     

Quantification of carbon nanotube dispersion and its correlation with mechanical and thermal properties of epoxy nanocomposites

An experimental study is carried out to quantitatively assess the dispersion quality of carbon nanotubes (CNTs) in epoxy matrix as a function of CNT variant and weight fraction. To this end, two weight fractions (0.05% and 0.25%) of as-grown, oxidized, and functionalized CNTs are used to process CNT/epoxy nanocomposites. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared analysis of different variants of CNTs are used to establish the efficiency of purification route. While the relative change in mechanical properties is investigated through tensile and micro-hardness testing, thermal conductivity of different nanocomposites is measured to characterize the effect of CNT addition on the average thermal properties of epoxy. Later on, a quantitative analysis is carried out to establish the relationship between the observed improvements in average composite properties with the dispersion quality of CNTs in epoxy. It is shown that carboxylic (-COOH) functionalization reduces the average CNT agglomerate size and thus ensures better dispersion of CNTs in epoxy even at higher CNT weight fraction. The improved dispersion leads to enhanced interfacial interaction at the CNT/epoxy interface and hence provides higher relative improvement in nanocomposite properties compared to the samples prepared using as-grown and oxidized CNTs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48879.     

Electrochemical deposition of poly[N,N′‐ethylene–bis(salicylideneiminato)–nickel(II)] nanobelts as electrode materials for supercapacitors

N,N′‐ethylene–bis(salicylideneiminato)]–nickel(II) [Ni(salen)] was synthesized in situ onto the surface of multiwalled carbon nanotubes via a one‐step potentiostatic electrodeposition as one‐dimensional nanobelts. The synthetic process was free of any templates or additives. Potential played a key role in the formation of the poly[N,N′‐ethylene–bis(salicylideneiminato)]–nickel(II)] {poly[Ni(salen)]} nanobelts, and the electrical conductivities of the poly[Ni(salen)] decreased with increasing deposition time. The capacitance values of poly[Ni(salen)] were 272, 195, and 146 F/g at 0.05 mA/cm² for deposition times of 10, 20, and 30 min, respectively. The capacitance of the sample with a particle structure was much lower than that of poly[Ni(salen)] with a nanobelt structure. The poly[Ni(salen)] nanobelts exhibited a better capacitive behavior than the poly[Ni(salen)] particles because the nanobelt structure made access for the charge and ion to the inner part of the electrode easier. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39561.     

Conductivity and intermolecular interactions in proton‐conducting gel electrolytes

Proton‐conducting gel electrolytes based on poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVdF), and mixtures of PMMA with PVdF or poly(vinyl chloride) doped by acid solutions in aprotic solvents were synthesized and are discussed in this article. The gel conductivity as a function of the concentrations of acid and polymer and the polymeric matrix composition has been analyzed. Extreme dependence of the conductivity on acid and polymer concentrations was found. It was revealed that within the acid concentration range studied, the gel conductivity was higher than the conductivity of the corresponding liquid electrolytes used for the synthesis. The increase in the electrical conductivity with the growth of the systems viscosity is discussed as an indication of a certain involvement of the polymer matrix in the increase of the charge carrier mobility within the frame of a Grotthuss mechanism. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40674.     

Matched‐dual‐polymer electrochromic lenses,using new cathodically coloring conducting polymers,with exceptional performance and incorporated into automated sunglasses

Reported are syntheses of several new monomer precursors of cathodically coloring conducting polymers (CPs), based on a propylene dioxythiophene skeleton. These are shown to yield CPs—both as homopolymers and as copolymers—that are nearly “perfectly” matched electrochemically and electrochromically with a set of anodically coloring poly(aromatic amines), for use in dual‐polymer electrochromic lenses. Resulting dual‐polymer electrochromic lenses display very high light/dark contrast (typically up to 70/7% or 50/0.5% Transmission (integrated over visible spectrum, vs. air reference), Haze < 2%, very high cyclability (> 10 K cycles), multiyear shelf life, appealing transparent to dark‐blue‐black transition, and excellent optical memory. Dramatic lowering of switching time, from 8 to < 1 s, is demonstrated using unique applied‐potential algorithm resident on inexpensive Microcontroller chip. Working, practical dual‐polymer electrochromic spectacles are demonstrated with electrochromic lenses retrofitted to spectacles meeting ANSI Z87.1, GL‐PD 10–12 (U.S. military) specifications. These incorporate photosensor, rechargeable Li battery, Microcontroller, allow for automated operation. Ab‐initio‐design spectacles, also conforming to above specifications, are also demonstrated, with components seamlessly hidden within frame. To the best of our knowledge, the electrochromic lenses and sunglasses reported herein represent the best visible‐region electrochromic performance for dual‐polymer CP electrochromic systems to date and the first practical implementation in working sunglasses. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41043.     

Chemical vapor deposition of poly(3‐alkylthiophene) nanoparticles on fabric: Chemical and electrochemical characterization

Chemical vapor deposition of poly(3‐methylthiophene) and poly (3‐hexylthiophene) as conductive polymers on the surface of polyester fabrics was successfully obtained. Fourier transform infrared spectroscopy confirmed the formation of polymers on surface of fabrics (the fingerprint of polythiophenes, υ 600–1500 cm^?1). The uniformity of deposition and nanoparticles (average size of 60 nm) were proved with scanning electron microscopy. Electrochemical impedance spectroscopy showed that P3HT‐coated samples offer higher conductivity in compared to P3MT‐coated samples. The impedance modulus of P3HT‐coated samples was lowered nine times to that of row materials and reached to c8000 Ω. The samples have also shown electrochromic properties under electrical current, changing its color from yellowish green at 0 V to dark green at +12 V for poly (3‐hexylthiophene) samples and from brown at 0 V to red at +12 V for poly(3‐methylthiophene)‐coated fabrics (V = 0 V, λ = 450 nm; V = 12 V, λ = 650 nm). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40673.