scholarly journals Graphene Oxide and Its Inorganic Composites: Fabrication and Electrorheological Response

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2185 ◽  
Author(s):  
Dong ◽  
Kim ◽  
Choi
Keyword(s):  
Graphene Oxide ◽  
Review Paper ◽  
Inorganic Materials ◽  
Flow Curves ◽  
Dielectric Characteristics ◽  
Oscillation Analysis ◽  
Inorganic Composites ◽  
Steady Shear Flow ◽  
Dynamic Yield ◽  
Er Fluids

Composite particles associated with graphene oxide (GO) and inorganic materials provide the synergistic properties of an appropriate electrical conductivity of GO with the good dielectric characteristics of inorganic materials, making them attractive candidates for electrorheological (ER) materials. This review paper focuses on the fabrication mechanisms of GO/inorganic composites and their ER response when suspended in a non-conducting medium, including steady shear flow curves, dynamic yield stress, On-Off tests, and dynamic oscillation analysis. Furthermore, the morphologies of these composites, dielectric properties, and sedimentation of the ER fluids are covered.

INFLUENCE OF SURFACTANTS ON PROPERTIES OF ELECTRORHEOLOGICAL FLUIDS CONTAINING POLYANILINE

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2461-2467 ◽  
Author(s):  
MAŁGORZATA BOCIŃSKA ◽  
HENRYK WYCIŚLIK ◽  
MARCIN OSUCHOWSKI ◽  
JANUSZ PŁOCHARSKI
Keyword(s):  
Yield Stress ◽  
Current Density ◽  
Silicone Oil ◽  
Flow Curves ◽  
Different Types ◽  
Order Of Magnitude ◽  
Dynamic Yield ◽  
Rate Of Sedimentation ◽  
Er Fluids

Sedimentation which is a natural process in most of ER fluids can be reduced by addition of surfactants that influence also other properties of the fluids. To study both the ER effect and the rate of sedimentation was the aim of the investigations. The ER fluids comprised powdered polyaniline and silicone oil to which surfactants of different polarity were added. The rate of sedimentation was measured by a sedimentation balance. The flow curves were recorded under electric field up to 2.5 kV/mm. Current density was also measured as a function of shear rate. It was found that the activity of a surfactant depends strongly on its polarity. The lipophylic surfactants stabilized the suspension very well but about 30% decrease of the dynamic yield stress was observed. The current density was reduced as well by almost one order of magnitude. The hydrophylic surfactants hardly stabilized the suspension but increase of yield stress was observed that was not followed by increase of current density. The role of different types of non-ionic surfactants was discussed.

scholarly journals A Comprehensive Review of Polymeric Wastewater Purification Membranes

2021 ◽  
Vol 5 (6) ◽  
pp. 162
Author(s):  
Rasmeet Singh ◽  
Mandeep Singh ◽  
Nisha Kumari ◽  
Janak ◽  
Sthitapragyan Maharana ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Pore Formation ◽  
Inorganic Materials ◽  
Special Focus ◽  
Nanocomposite Membranes ◽  
Wastewater Purification ◽  
Comprehensive Review ◽  
Synthetic Membranes ◽  
Purification Membranes ◽  
Thermal And Chemical Stability

Synthetic membranes are currently employed for multiple separation applications in various industries. They may have been prepared from organic or inorganic materials. Present research majorly focuses on polymeric (i.e., organic) membranes because they show better flexibility, pore formation mechanism, and thermal and chemical stability, and demand less area for installation. Dendritic, carbon nanotube, graphene and graphene oxide, metal and metal oxide, zwitter-ionic, and zeolite-based membranes are among the most promised water treatment membranes. This paper critically reviews the ongoing developments to utilize nanocomposite membranes to purify water. Various membranes have been reported to study their resistance and fouling properties. A special focus is given towards multiple ways in which these nanocomposite membranes can be employed. Therefore, this review provides a platform to develop the awareness of current research and motivate its readers to make further progress for utilizing nanocomposite membranes in water purification.

scholarly journals Fabrication of graphene oxide/montmorillonite nanocomposite flexible thin films with improved gas-barrier properties

RSC Advances ◽  
2018 ◽  
Vol 8 (68) ◽  
pp. 39083-39089 ◽  
Author(s):  
Se Jung Kim ◽  
Tan young Kim ◽  
Byung Hyun Kang ◽  
Gun-Hwan Lee ◽  
Byeong-Kwon Ju
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Barrier Properties ◽  
Inorganic Materials ◽  
Gas Barrier ◽  
Gas Barrier Properties

Nanocomposites are potential substitutes for inorganic materials in fabricating flexible gas-barrier thin films.

ELECTRORHEOLOGICAL EFFECT OF CONDUCTIVE POLYMERS DISPERSED IN LIQUID CRYSTALLINE MATRIX

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1135-1141 ◽  
Author(s):  
MONIKA CISZEWSKA ◽  
JANUSZ PLOCHARSKI
Keyword(s):  
Liquid Crystalline ◽  
Silicone Oil ◽  
Crystalline Polymer ◽  
Electrorheological Fluids ◽  
Flow Curves ◽  
Homogeneous Solutions ◽  
Electrorheological Effect ◽  
Active Liquid ◽  
Er Fluids ◽  
Crystalline Matrix

Hybrid electrorheological fluids comprising powdered conjugated polymers dispersed in solutions of a liquid crystalline polymer were prepared and studied. FeCl 3 doped poly(p-phenylene) and pyrolised polyacrylonitrile were chosen as the dispersed phase and poly(n-hexyl isocyanate) dissolved in xylene was used as the active liquid matrix. All the component materials were extensively characterized by various methods. Flow curves of the hybrid ER fluids were recorded under electric field and compared with analogous curves obtained for dispersions of the powders in silicone oil and with homogeneous solutions of the LC polymer in xylene. A very significant enhancement of the ER effect in the studied hybrid fluids was observed.

scholarly journals Syntheses Approach of 2-D Oxide Family of Graphene for Supercapacitor Application (A-Review)

2020 ◽  
Vol 36 (6) ◽  
pp. 1016-1025
Author(s):  
PARIMAL ROUTH
Keyword(s):  
Graphene Oxide ◽  
Mechanical Strength ◽  
Surface Area ◽  
Review Paper ◽  
Modern Science ◽  
Large Surface Area ◽  
Synthetic Methods ◽  
Supercapacitor Application ◽  
Material Chemistry ◽  
Reduced Graphene

More recently, 2-D graphene oxide (GO)/reduced graphene (rGO) have altered the direction of modern science with material chemistry and physics by research as they offer different key advantages. These are (i) atomically thin 2-D nanosheets (NSs) provide a large surface area (ii) presence of maximum chemically reactive sites, and (iii) higher mechanical strength and flexibility. Considering the progresses of graphene research, we broadly and crucially discuss the formation of the growing family of 2-D GO/rGO in this review paper. Synthesis methodologies are compared, focusing to offer signs for emerging novel and adaptable synthetic methods. Their advantage use in the fields of supercapacitor are highlighted in this review.

Yield Stress of Emulsions and Suspensions as Measured in Steady Shearing and in Oscillations

2008 ◽  
Vol 18 (4) ◽  
pp. 44790-1-44790-8 ◽  
Author(s):  
I. Masalova ◽  
A.Ya. Malkin ◽  
R. Foudazi
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Yield Stress ◽  
Flow Curves ◽  
Dynamic Yield Stress ◽  
Shear Rates ◽  
Meaningful Material ◽  
Dynamic Yield ◽  
Steady Shearing ◽  
Concentrated Emulsions

Abstract The yield stresses of five samples (two highly concentrated emulsions, two Kaolin dispersions and mayonnaise) were determined in two ways. In one case, steady shear experiments were performed over a range of incrementally decreasing shear rates. The resulting flow curves, plotted as shear stress against shear rate, clearly showed the existence of a yield stress for each sample, the Herschel-Bulkley model being fitted to obtain values. In the second case, oscillatory amplitude sweeps were performed at three frequencies, and the “dynamic yield stress” was defined as the stress at which deviation from linearity occurred; this procedure has often been used to determine the yield stress of emulsions. It was found that the dynamic yield stress is frequency dependent, and cannot therefore be thought of as physically meaningful material property. At no frequency did the dynamic yield stress correlate with the yield stress obtained from the flow curves.

Preparation and characterization of electro-responsive core-sheath fiber mats for smart materials

2016 ◽  
Vol 87 (9) ◽  
pp. 1142-1151 ◽  
Author(s):  
Se Young Oh ◽  
Tae Jin Kang
Keyword(s):  
Smart Materials ◽  
Inorganic Materials ◽  
Electrospinning Technique ◽  
Fiber Mats ◽  
The Core ◽  
Potential Applications ◽  
Multi Walled Carbon Nanotubes ◽  
Er Fluids ◽  
Core Part ◽  
Sheath Structure

Multi-walled carbon nanotubes coated with inorganic materials were spun with polyethylene terephthalate with a core-sheath structure using co-axial electrospinning technique. The effect of electrorheological (ER) particle content on the morphology, rheological and mechanical properties has been studied. It has been shown that ER particles were homogeneously distributed throughout the core part of the fibers with the core-sheath structure. It has been uniformly fabricated by controlling the viscosity and conductivity of ER fluids as well as the applied voltage, feeding rate of the electrospinning systems. The tensile test results with fiber mats showed that the modulus and tensile strength of the fiber mats is enhanced with lower breaking elongation because of the instant increase of viscosity and yield stress of ER fluid in the core part under the external applied electric field. Fiber mats with ER fluids in the core of the fiber may find potential applications in the area of adaptive textile structures.

scholarly journals The Magnetization of a Composite Based on Reduced Graphene Oxide and Polystyrene

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 403
Author(s):  
Alexander N. Ionov ◽  
Mikhail P. Volkov ◽  
Marianna N. Nikolaeva ◽  
Ruslan Y. Smyslov ◽  
Alexander N. Bugrov
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Covalent Bonds ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Inorganic Composites ◽  
Reduced Graphene ◽  
Type Ii Superconductivity

The use of reduced graphene oxide (r-GO) is a promising way of fabricating organic–inorganic composites with unique electrical and magnetic properties. In our work, polystyrene/r-GO composites were synthesized, in which both the components are linked together by covalent bonds. The r-GO used differs from the graphene obtained from graphite through mechanical exfoliation using the ‘scotch tape’ by presenting many structural defects. Binding in the composite structure between the components was confirmed by infrared spectroscopy. Elemental analysis was carried out by energy dispersive X-ray spectroscopy. Scanning electron microscopy, X-ray diffraction, and Raman spectroscopy were used to monitor the 2D-order in exfoliated r-GO galleries. Using a vibrating-sample magnetometer, we have shown that the composite magnetization loops demonstrate type-II superconductivity up to room temperature due to r-GO flakes. We believe that a strain field in the r-GO flakes covalently binding to a polymeric matrix is responsible for the superconductivity phenomena.

HYSTERESIS PHENOMENON IN FLOW-CURVES OF ER FLUIDS CONTAINING SULFONATED POLYMER PARTICLES

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1070-1077 ◽  
Author(s):  
RYUJI AIZAWA ◽  
SHEILA L. VIEIRA ◽  
MASAMI NAKANO ◽  
YOSHINOBU ASAKO
Keyword(s):  
Shear Rate ◽  
Electric Field ◽  
Volume Fraction ◽  
Hysteresis Phenomenon ◽  
Polymer Particles ◽  
Concentric Cylinder ◽  
Flow Curves ◽  
Shear Rates ◽  
Dispersed Particles ◽  
Er Fluids

The ER fluids containing sulfonated polymer particles were continuously sheared at increasing and decreasing shear rates using a rotary concentric cylinder rheometer and the hysteresis in the up- and down-flow-curves were analyzed. The ER fluids show hysteresis of shear stress and current density. The up-curve (when shear rate increased) was located below the down-curve (when shear rate decreased). As the electric field increased, the area in the hysteresis curves increased. The hysteresis depended on the electric field strength, the time of the applied electric field, the volume fraction of particles and the water content of the particles. Hysteresis phenomenon was explained, based on the formation of agglomerations of dispersed particles in the ER fluid and on changes of the lamellar formations

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