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Electroactive Polymers (electroactive + polymer)

Distribution by Scientific Domains

Polymers and Materials Science	83%

Selected Abstracts

Electroactive Polymer with Oligoanilines in the Main Chain: Synthesis, Characterization and Dielectric Properties

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 20 2009
Junfeng Zhang
Abstract An electroactive polymer with well-defined oligoanilines in the main chain has been prepared by oxidative coupling polymerization. The detailed characteristics of the polymer were systematically studied by FT-IR, 1H NMR, GPC and XRD. Its electrochemical behavior was explored with UV-Vis spectra and cyclic voltammetry showing that its intrinsic electroactivity was maintained and exhibited three distinct reversible oxidative states. Its electrical conductivity is about 3.91,×,10,4,S,·,cm,1 in HCl-doped form at room temperature. Furthermore, the polymer displays a dielectric constant of 48.4 and 13.6 at 10 and 1,MHz, respectively, mainly attributed to the improvement in delocalized charge density and electrical conductivity of the polymer by introduction of the conjugated oligoaniline segments. [source]

Electrolyte Effects on Charge Transport Behavior of [Os(bpy)2(PVP)10Cl]Cl and [Ru(bpy)2(PVP)10Cl]Cl Redox Polymers in Ultra-Thin Films of Polyions

ELECTROANALYSIS, Issue 18 2005
Bingquan Wang
Abstract Metallopolymer films have important applications in electrochemical catalysis. The alternate electrostatic layer-by-layer method was used to assemble films of [Ru(bpy)2(PVP)10Cl]Cl (denoted as ClRu-PVP) and [Os(bpy)2(PVP)10Cl]Cl (ClOs-PVP) metallopolymers onto pyrolytic graphite electrodes. Film thickness estimated by quartz crystal microbalance was 6,8,nm. The effects of pH, electrolyte species and concentration on the electrochemical properties of these electroactive polymers were studied using cyclic voltammetry (CV). Behavior in various electrolytes was compared. Also the mass changes within the ultra-thin film during redox of Os2+/3+ were characterized by in situ electrochemical quartz crystal microbalance (EQCM). The results indicate rapid reversible electron transfer, and show that both ClRu-PVP and ClOs-PVP have compact surface structures while ClOs-PVP is a little denser than ClRu-PVP. Although hydrogen ions do not participate in the chemical reaction of either film, the movement of Na+ cation and water accompanies the redox process of ClOs-PVP films. [source]

Silicone,Poly(hexylthiophene) Blends as Elastomers with Enhanced Electromechanical Transduction Properties,

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2008
F. Carpi
Abstract Dielectric elastomers are progressively emerging as one of the best-performing classes of electroactive polymers for electromechanical transduction. They are used for actuation devices driven by the so-called Maxwell stress effect. At present, the need for high-driving electric fields limits the use of these transduction materials in some areas of potential application, especially in the case of biomedical disciplines. A reduction of the driving fields may be achieved with new elastomers offering intrinsically superior electromechanical properties. So far, most attempts in this direction have been focused on the development of composites between elastomer matrixes and high-permittivity ceramic fillers, yielding limited results. In this work, a different approach was adopted for increasing the electromechanical response of a common type of dielectric elastomer. The technique consisted in blending, rather than loading, the elastomer (poly(dimethylsiloxane)) with a highly polarizable conjugated polymer (undoped poly(3-hexylthiophene)). The resulting material was characterised by dielectric spectroscopy, scanning electron microscopy, tensile mechanical analysis, and electromechanical transduction tests. Very low percentages (1,6 wt %) of poly(3-hexylthiophene) yielded both an increase of the relative dielectric permittivity and an unexpected reduction of the tensile elastic modulus. Both these factors synergetically contributed to a remarkable increase of the electromechanical response, which reached a maximum at 1 wt % content of conjugated polymer. Estimations based on a simple linear model were compared with the experimental electromechanical data and a good agreement was found up to 1 wt %. This approach may lead to the development of new types of materials suitable for several types of applications requiring elastomers with improved electromechanical properties. [source]

Effect of conjugated core building block dibenzo[a,c]phenazine unit on ,-conjugated electrochromic polymers: Red-shifted absorption

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2010
Elif Kose Unver
Abstract A comparative investigation was undertaken for the electrosynthesis and electrochemical properties of three different electroactive polymers having a conjugated core building block, dibenzo[a,c]phenazine. A series of monomers has been synthesized as regards to thiophene based units; thiophene, 3-hexyl thiophene, and 3,4-ethylenedioxythiophene. The effects of different donor substituents on the polymers' electrochemical properties were examined by cyclic voltammetry. Introducing highly electron-donating (ethylene dioxy) group to the monomer enables solubility while also lowering the oxidation potential. The planarity of the monomer unit enhances ,-stacking and consequently lowering the Eg from 2.4 eV (PHTP) to 1.7 (PTBP). Cyclic voltammetry and spectroelectrochemical measurements revealed that 2,7-bis(4-hexylthiophen-2-yl)dibenzo[a,c]phenazine (HTP) and 2,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)dibenzo[a,c]phenazine (TBP) possessed electrochromic behavior. The colorimetry analysis revealed that while PTBP have a color change from red to blue, PHTP has yellow color at neutral state and blue color at oxidized state. Hence the presence of the phenazine derivative as the acceptor unit causes a red shift in the polymers' absorption to have a blue color. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1714,1720, 2010 [source]

Synthesis and characterization of polyaniline derivative and silver nanoparticle composites

POLYMER INTERNATIONAL, Issue 10 2008
Gururaj M Neelgund
Abstract BACKGROUND: There has been a recent surge of interest in the synthesis and applications of electroactive polymers with incorporated metal nanoparticles. These hybrid systems are expected to display synergistic properties between the conjugated polymers and the metal nanoparticles, making them potential candidates for applications in sensors and electronic devices. RESULTS: Composites of polyaniline derivatives,polyaniline, poly(2,5-dimethoxyaniline) and poly(aniline-2,5-dimethoxyaniline),and silver nanoparticles were prepared through simultaneous polymerization of aniline derivative and reduction of AgNO3 in the presence of poly(styrene sulfonic acid) (PSS). We used AgNO3 as one of the initial components (1) to form the silver nanoparticles and (2) as an oxidizing agent for initiation of the polymerization reaction. UV-visible spectra of the synthesized nanocomposites reveal the synchronized formation of silver nanoparticles and polymer matrix. The morphology of the silver nanoparticles and degree of their dispersion in the nanocomposites were characterized by transmission electron microscopy. Thermogravimetric analysis and differential scanning calorimetry results indicate an enhancement of the thermal stability of the nanocomposites compared to the pure polymers. The electrical conductivity of the nanocomposites is in the range 10,4 to 10,2 S cm,1. CONCLUSION: A single-step process for the synthesis of silver nanoparticle,polyaniline derivative nanocomposites doped with PSS has been demonstrated. The approach in which silver nanoparticles are formed simultaneously during the polymerization process results in a good dispersion of the nanoparticles in the conductive polymer matrix. Copyright © 2008 Society of Chemical Industry [source]