scholarly journals Dielectric Polarization and Electrorheological Response of Poly(ethylaniline)-Coated Reduced Graphene Oxide Nanoflakes with Different Reduction Degrees

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2528
Author(s):  
Yudong Wang ◽  
Min Yang ◽  
Honggang Chen ◽  
Xiaopeng Zhao ◽  
Jianbo Yin
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Electric Fields ◽  
Flow Instability ◽  
Interfacial Polarization ◽  
Simultaneous Action ◽  
Dielectric Polarization ◽  
Polarization Rate ◽  
Reduced Graphene ◽  
The Difference

We prepared poly(ethylaniline)-coated graphene oxide nanoflakes and then treated them with different concentrations of hydrazine solution to form dielectric composite nanoflakes having different reduction degrees of reduced graphene oxide core and insulating polyethylaniline shell (PEANI/rGO). The morphology of PEANI/rGO was observed by scanning electron microscopy, while the chemical structure was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectrometer. The influence of reduction degrees on the conductivity, dielectric polarization and electrorheological effect of PEANI/rGO in suspensions was investigated by dielectric spectroscopy and rheological test under electric fields. It shows that the PEANI/rGO has two interfacial polarization processes respectively due to rGO core and PEANI shell. As the number of hydrazine increases, the conductivity and polarization rate of rGO core increase. As a result, the difference between the polarization rate of rGO core and that of the PEANI shell gradually becomes large. This increased difference does not significantly decrease the yield stress but causes the flow instability of PEANI/GO suspensions under the simultaneous action of electric and shear fields.

Strong interfacial polarization in ZnO decorated reduced-graphene oxide synthesized by molecular level mixing

2015 ◽  
Vol 17 (26) ◽  
pp. 17237-17245 ◽  
Author(s):  
Rama Krishna Jammula ◽  
Suresh Pittala ◽  
Sanyadhanam Srinath ◽  
Vadali V. S. S. Srikanth
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Molecular Level ◽  
Interfacial Polarization ◽  
Reduced Graphene

scholarly journals Tailoring of enhanced interfacial polarization in WO3 nanorods grown over reduced graphene oxide synthesized by a one-step hydrothermal method

RSC Advances ◽  
2017 ◽  
Vol 7 (23) ◽  
pp. 13985-13996 ◽  
Author(s):  
Bilal Ahmed ◽  
Animesh K. Ojha ◽  
Florian Hirsch ◽  
Ingo Fischer ◽  
Donfack Patrice ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hydrothermal Method ◽  
Reduced Graphene Oxide ◽  
Present Report ◽  
Interfacial Polarization ◽  
One Pot ◽  
Reduced Graphene ◽  
One Step

In the present report, well-defined WO3 nanorods (NRs) and a rGO–WO3 composite were successfully synthesized using a one-pot hydrothermal method.

scholarly journals Gas sensors based on dielectrophoresis of graphene, and graphene oxide, and reduced graphene oxide A Review

2020 ◽  
Author(s):  
shamim Azimi
Keyword(s):  
Graphene Oxide ◽  
Electric Field ◽  
Reduced Graphene Oxide ◽  
Electric Fields ◽  
Surrounding Medium ◽  
Diagnostic Technique ◽  
Environmental Research ◽  
Label Free ◽  
Reduced Graphene ◽  
Electrode Edge

Dielectrophoresis (DEP) is a label-free, accurate, fast, and low-cost diagnostic technique that uses the principles of polarization and the motion of bioparticles in applied electric fields. DEP occurs when uncharged particles in the solution are subject to a spatially non-uniform alternating-current (AC) electric field, resulting in the motion of particles by creating a polarizability gradient between the particles and the suspending medium. The movement of particles in DEP is based on the difference in polarizability between the particles and the surrounding medium. If the particles move toward the electrode edge, the region of high electric field gradient, the response is called positive DEP (p-DEP). At the same time, if the particles move away from the electrode edge, the response is called negative DEP (n-DEP). This phenomenon provides a powerful and versatile tool for the non-destructive manipulation of nanoscale materials, allowing for the control of the resistance and the type of the assembly. This technique has been proven to be beneficial in various fields, including environmental research, polymer research, sensors, biosensors, microfluidics, medicine, and diagnostics. This paper reviews the fundamentals of DEP and its specific application in the incorporation of graphene, graphene oxide(GO), and reduced graphene oxide(RGO), enabling the assembly of individual two-dimensional nanostructures at predefined locations in microdevices for gas sensor applications. The review provides an essential framework for parallel fabrication approaches of graphene-based devices.

scholarly journals NiS2@MoS2 Nanospheres Anchored on Reduced Graphene Oxide: A Novel Ternary Heterostructure with Enhanced Electromagnetic Absorption Property

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 292 ◽  
Author(s):  
Zhi Zhang ◽  
Xuliang Lv ◽  
Yiwang Chen ◽  
Pin Zhang ◽  
Mingxu Sui ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Impedance Matching ◽  
Interfacial Polarization ◽  
Effective Bandwidth ◽  
Military Equipment ◽  
Electromagnetic Absorption ◽  
Reduced Graphene ◽  
Absorption Performance ◽  
Minimum Reflection Loss

For the purposes of strength, military equipment camouflage, and protecting the health of organisms, electromagnetic wave absorbing materials have received a lot of attention and are widely studied. In addition to having a strong absorption intensity and a wide effective absorption bandwidth, materials that are lightweight, thermally stable, and antioxidative are also highly desirable. In this study, we fabricated core–shell structured NiS2@MoS2 nanospheres anchored on reduced graphene oxide (rGO) nanosheets (NiS2@MoS2/rGO) by a simple two-step hydrothermal method. The combination ratio was adjusted to achieve proper impedance matching. The electromagnetic parameters and the absorption performance were investigated in detail. A composite loaded with 30 wt.% of the sample achieved a minimum reflection loss (RL) value of −29.75 dB and the effective bandwidth (RL value of less than −10 dB) ranged from 4.95 GHz to 18.00 GHz (13.05 GHz), with a thickness ranging from 1.5 mm to 4.0 mm. This study proved that the generated significant interfacial polarization and synergetic interaction between components can result in NiS2@MoS2/rGO composites with enhanced electromagnetic absorption performance.

scholarly journals The Role of Reduced Graphene Oxide in the Suspension Polymerization of Styrene and Its Effect on the Morphology and Thermal Properties of the Polystyrene/rGO Nanocomposites

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1468
Author(s):  
Marta Sieradzka ◽  
Janusz Fabia ◽  
Dorota Biniaś ◽  
Ryszard Fryczkowski ◽  
Jarosław Janicki
Keyword(s):  
Graphene Oxide ◽  
Thermal Properties ◽  
Reduced Graphene Oxide ◽  
Suspension Polymerization ◽  
Decomposition Temperature ◽  
Reduced Graphene ◽  
The Difference ◽  
Polar Functional Groups

Reduced graphene oxide (rGO) was used to obtain Polystyrene (PS)/rGO nanocomposites via in-situ suspension polymerization. The main goal of the article was to determine how rGO influences the morphology and thermal properties of PS beads. The obtained samples were studied by means of a scanning electron microscope (SEM), and calorimetric and thermogravimetric analysis (DCS, TGA). It was proven that the addition of rGO, due to the presence of polar functional groups, causes significant changes in bead sizes and size distribution, and in their morphology (on the surface and in cross-section). The increasing amount of rGO in the polymer matrix increased the size of beads from 0.36 to 3.17 mm for pure PS and PS with 0.2 wt% rGO content, respectively. PS/rGO nanocomposites are characterized by distinctly improved thermostability, which is primarily expressed in the increase in their decomposition temperature. For a sample containing 0.3 wt% rGO, the difference is more than 12 °C in comparison to pure PS beads.

scholarly journals Electric Field Grading Material Based on Thermally Reduced Graphene Oxide

2017 ◽  
Author(s):  
W. Li ◽  
U. W Gedde ◽  
H. Hillborg
Keyword(s):  
Graphene Oxide ◽  
Electric Field ◽  
Reduced Graphene Oxide ◽  
Electric Fields ◽  
Silicone Rubber ◽  
Rubber Matrix ◽  
Reduced Graphene ◽  
Rubber Composite ◽  
Non Linear ◽  
A Minor

<p>Silicone rubber filled with low amounts of thermally<br />reduced graphene oxide exhibit non-linear conductivity<br />with exposed to increased electric fields. Such material<br />can be interesting as electric field grading material in<br />HVDC cable accessories. In this study graphene oxide<br />was thermally reduced (rGO) at 120 and 180 °C during<br />12 hours in a hot air oven. The reduction was confirmed<br />by TGA and FTIR. 3 wt.% rGO was then dispersed in a<br />silicone rubber matrix and homogenous dispersion was<br />demonstrated by the scanning electron microscopy. The<br />rGO-filled silicone rubber (120 and 180 °C reduced)<br />exhibited a non-linear resistivity when exposed to an<br />increasing electric (DC) field. The conductivity<br />decreased from 10^14 to 10^11 Ohm m when the electric<br />field increasing from 0.2 to 6 kV/mm. The onset of the<br />non-linear conduction occurred in the range of 1 – 2<br />kV/mm. The long-term stability of the conductivity of<br />the silicone rubber composite was tested. After 47 days<br />ageing at 120 °C, therGO/silicone rubber composite<br />exhibited a slight increase in the onset of non-linear<br />conduction, as well as a minor increase in resistivity.</p>

On the sign of the relaxation activation energy for interfacial polarization in reduced graphene oxide–based nano-composites

2016 ◽  
Vol 109 (18) ◽  
pp. 182901 ◽  
Author(s):  
Rakibul Islam ◽  
Anthony N. Papathanassiou ◽  
Roch Chan-Yu-King ◽  
Frédérick Roussel
Keyword(s):  
Activation Energy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Interfacial Polarization ◽  
Nano Composites ◽  
Reduced Graphene
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