#1Elisa Hellen Segundo(UDESC: Universidade do Estado de Santa Catarina)H-Index: 2
#2Luis Cesar Fontana(UDESC: Universidade do Estado de Santa Catarina)H-Index: 8
Last. Daniela Becker(UDESC: Universidade do Estado de Santa Catarina)H-Index: 12
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Abstract Graphene nanosheets were produced by graphite exfoliation through underwater electrical discharge, also known as plasma underwater. Graphite particles were dispersed in different solvents with different ratios between polar and dispersive surface tension components (pure water and an aqueous solution of isopropyl alcohol (IPA) at different concentrations (1:1 and 7:3 IPA:Water)) under constant stirring and low voltage pulses (about 1.5 kV). Even under relative low voltage, the productio...
Polyaniline nanostructures have been synthesized by self-assembly method by varying the dopant to monomer molar ratio. High resolution transmission electron micrographs show how the dopant to monomer molar ratio influences on the morphology and structure. The temperature dependence of dc conductivity study shows semiconducting behavior. From dc conductivity study it has been observed that conductivity increases with increasing dopant concentration and maximum conductivity is attained at dopant t...
Abstract The room-temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium tetrafluoroborate, BMIM BF 4 , was employed as electrolyte in the electrosynthesis of thin polypyrrole (PPy) films on a Pt substrate, and the resulting PPy electrodes were electrochemically characterized. Electrochemical impedance spectroscopy (EIS) was used to comparatively investigate the electric behavior of PPy produced in the RTIL and the one produced in a traditional acetonitrile/lithium salt system, and charge–d...
Abstract Plasma polymerization of aniline is carried out by means of continuous RF and pulsed DC glow discharge plasma in a common reactor at different applied powers. The discharge control variables are optimized for good quality film growth and the role of fragmentation of the molecular structure on the structural, optical, morphological and optophysical properties of the deposited plasma polymerized aniline (PPAni) layers is investigated. Retention of the conjugated structure is found to be p...
Abstract Vapour phase polymerisation (VPP) is a well established technique in which the monomer is introduced to an oxidant-coated substrate in vapour form. Polymerisation then takes place at the oxidant vapour interface. VPP is a technique that could be used to immobilise materials to the modified electrode surface. This review article concentrates on the VPP of conducting polymers such as Polypyrrole (PPy) polythiophen (PT) and polyaniline (PANi). VPP of conducting polymers and other non-condu...
Maleic anhydride plasma polymer was deposited at the surface of carbon fibers and functionalized with vinyl and thiol groups to improve its adhesion strength with an acrylate matrix cured by an electron beam. A characterization of the fiber surface properties was done before and after coating (topography, surface chemistry, and surface energy). Sharp improvements of the interfacial shear strength (+ 120%), measured by a micromechanical test derived from the pull-out test, were obtained and, to t...
Abstract Uniform treatment of multiwalled carbon nanotubes by plasma treatment has been investigated using a custom-built stirring plasma system. A thin plasma polymer with high levels of amine groups has been deposited on MWCNTs using a combination of continuous wave and pulsed plasma polymerization of heptylamine in the stirring plasma system. Scanning electron microscopy showed that the plasma polymerization improved the dispersion and interfacial bonding of the MWCNTs with an epoxy resin at ...
#1Jörg Friedrich(BAM: Bundesanstalt für Materialforschung und -prüfung)H-Index: 23
Several reaction mechanisms have been proposed for the formation of plasma polymers, such as monomer fragmentation followed by poly-recombination into randomly structured and crosslinked films; fragmentation, accompanied by the formation of acetylene or other film-forming intermediates and deposition of polystyrene-like material; plasma-initiation of a radical chain-growth polymerization; and ion-molecule reactions, as well as ionic chain-growth polymerization. The bulk structure of plasma polym...
The polymerization of aniline under continuous and pulsed RF-plasma conditions is studied using the same plasma reactor. The effects of input power, on and off-times, frequency and duty cycle variations on the growth kinetics and on the chemical structure of the obtained layers are examined. The chemical structure of the films is characterized using Fourier Transform Infra-Red, X-ray photoelectron and UltraViolet–Visible spectroscopies. The thickness of the films is determined by profilometry. T...
Suitable modifications are done in a RF sputtering set up to facilitate synthesis of polyaniline thin film by RF-plasma polymerization process. The synthesized films are characterized by FTIR, XRD, Ellipsometry, UV–visible absorption & reflection and SEM. The films prepared are highly cross-linked, amorphous in nature and have band gap of 2.07 eV. SEM images show the uniformity in film morphology. The refractive index of the films is determined to be 1.11 and dielectric constant is 1.12 at a wav...