scholarly journals Directional freezing of binary colloidal suspensions: a model for size fractionation of graphene oxide

Soft Matter ◽  
2019 ◽  
Vol 15 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Xin Xu ◽  
Luofu Liu ◽  
Hongya Geng ◽  
Jianjun Wang ◽  
Jiajia Zhou ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Theoretical Model ◽  
Colloidal Particles ◽  
Colloidal Suspensions ◽  
Size Fractionation ◽  
Preferential Adsorption ◽  
Directional Freezing ◽  
Ice Phase

A theoretical model of a binary colloid suspension was developed by incorporating both the moving freezing boundary and the preferential adsorption of colloidal particles to the ice phase.

scholarly journals Lyotropic Liquid Crystals from Colloidal Suspensions of Graphene Oxide

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 455 ◽  
Author(s):  
Adam P. Draude ◽  
Ingo Dierking
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Colloidal Particles ◽  
Colloidal Suspensions ◽  
Lyotropic Liquid Crystals ◽  
Nanoscience And Nanotechnology ◽  
And Behavior

Lyotropic liquid crystals from colloidal particles have been known for more than a century, but have attracted a revived interest over the last few years. This is due to the developments in nanoscience and nanotechnology, where the liquid crystal order can be exploited to orient and reorient the anisotropic colloids, thus enabling, increasing and switching the preferential properties of the nanoparticles. In particular, carbon-based colloids like carbon nanotubes and graphene/graphene–oxide have increasingly been studied with respect to their lyotropic liquid crystalline properties over the recent years. We critically review aspects of lyotropic graphene oxide liquid crystal with respect to properties and behavior which seem to be generally established, but also discuss those effects that are largely unfamiliar so far, or as of yet of controversial experimental or theoretical outcome.

Size Fractionation of Graphene Oxide Nanosheets via Controlled Directional Freezing

2017 ◽  
Vol 139 (36) ◽  
pp. 12517-12523 ◽  
Author(s):  
Hongya Geng ◽  
Bowen Yao ◽  
Jiajia Zhou ◽  
Kai Liu ◽  
Guoying Bai ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Size Fractionation ◽  
Graphene Oxide Nanosheets ◽  
Directional Freezing

Aggregation of binary colloidal suspensions on attractive walls

2016 ◽  
Vol 18 (4) ◽  
pp. 3073-3079 ◽  
Author(s):  
Aleena Laganapan ◽  
Davide Bochicchio ◽  
Marguerite Bienia ◽  
Arnaud Videcoq ◽  
Riccardo Ferrando
Keyword(s):  
Solid Surface ◽  
Colloidal Particles ◽  
Biological Systems ◽  
Colloidal Suspensions ◽  
Fundamental Importance

The adsorption of colloidal particles from a suspension on a solid surface is of fundamental importance to many physical and biological systems.

Graphene oxide based dopamine mussel-like cross-linked polyethylene imine nanocomposite coating with enhanced hexavalent uranium adsorption

2019 ◽  
Vol 7 (28) ◽  
pp. 16902-16911 ◽  
Author(s):  
Songwei Li ◽  
Peipei Yang ◽  
Xianhu Liu ◽  
Jiaoxia Zhang ◽  
Wei Xie ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Active Sites ◽  
Nanocomposite Coating ◽  
Polyethylene Imine ◽  
Uranium Adsorption ◽  
Hexavalent Uranium ◽  
Preferential Adsorption ◽  
Excellent Stability

GO-pDA-PEI with excellent stability provided enough movement space and active sites for highly preferential adsorption of U(vi).

Liquid Crystal Behavior of V2O5·nH2O Gels

1998 ◽  
Vol 547 ◽  
Author(s):  
J. Livage ◽  
P. Davidson ◽  
X. Commeinhes ◽  
O. Pelletier
Keyword(s):  
Liquid Crystal ◽  
Vanadium Pentoxide ◽  
Colloidal Particles ◽  
Organic Molecules ◽  
Polarized Light ◽  
Colloidal Suspensions ◽  
Acid Dissociation ◽  
Polymeric Particles ◽  
Nematic Phases ◽  
Electrostatic Repulsions

AbstractMost liquid crystals are made of organic molecules, very few of them are based on mineral compounds. Vanadium pentoxide gels and sols have been shown to give mesophases. They are made of ribbon-like polymeric particles of vanadium pentoxide dispersed in water. Ansitropic xerogel layers are formed when these gels are deposited and dried onto flat substrates. Dehydration is reversible and fluid phases are again obtained via a swelling process when water is added to the xerogel.When observed by polarized light microscopy, colloidal suspensions of V2O5 ribbons display defects typical of lyotropic nematic phases. Dilute nematic suspensions can even be oriented by applying a magnetic field of about 0.5 Tesla. Such a liquid crystal behavior is mainly due to the highly anisotropic shape of vanadium oxide colloidal particles. Acid dissociation at the oxide/water interface gives rise to surface electrical charges and electrostatic repulsions should also be responsible for the stabilization of the nematic phase.

scholarly journals THE ELECTRICAL CONDUCTANCE OF SUSPENSIONS OF ELLIPSOIDS AND ITS RELATION TO THE STUDY OF AVIAN ERYTHROCYTES

1940 ◽  
Vol 23 (6) ◽  
pp. 753-771 ◽  
Author(s):  
Sidney Velick ◽  
Manuel Gorin
Keyword(s):  
Electrical Resistance ◽  
Colloidal Particles ◽  
Electrical Conductance ◽  
Colloidal Suspensions ◽  
Optical Methods ◽  
Flow Cells ◽  
Flow Method ◽  
Avian Erythrocytes

1. The theory of electrical conductance of colloidal suspensions has been extended to cover the case of ellipsoids with three axes different. 2. The results have been applied to suspensions of ellipsoidal erythrocytes of birds. 3. It has been shown that fluctuations in electrical resistance of suspensions of erythrocytes after stirring are due to streaming orientation of the cells. 4. The theory has been extended to cover four cases of orientation and tested experimentally in specially designed flow cells by electrical and optical methods. 5. Application of the flow method to the study of the shape of colloidal particles is discussed.

Dielectrophoretic Mixing With Novel Electrode Geometry

2009 ◽  
Author(s):  
G. Naga Siva Kumar ◽  
Sushanta K. Mitra ◽  
Subir Bhattacharjee
Keyword(s):  
Electric Field ◽  
Cell Activation ◽  
Colloidal Particles ◽  
Colloidal Suspension ◽  
Three Dimensional ◽  
Colloidal Suspensions ◽  
Navier Stokes ◽  
Mixing Efficiency ◽  
Computational Domain ◽  
Element Analysis

Electrokinetic mixing of analytes at micro-scale is important in several biochemical applications like cell activation, DNA hybridization, protein folding, immunoassays and enzyme reactions. This paper deals with the modeling and numerical simulation of micromixing of two different types of colloidal suspensions based on principle of dielectrophoresis (DEP). A mathematical model is developed based on Laplace, Navier-Stokes, and convection-diffusion-migration equations to calculate electric field, velocity, and concentration distributions, respectively. Mixing of two colloidal suspensions is simulated in a three-dimensional computational domain using finite element analysis considering dielectrophoretic, gravitational and convective (advective)–diffusive forces. Phase shifted AC signal is applied to the alternating electrodes for achieving the mixing of two different colloidal suspensions. The results indicate that the electric field and DEP forces are maximum at the edges of the electrodes and become minimum elsewhere. As compared to curved edges, straight edges of electrodes have lower electric field and DEP forces. The results also indicate that DEP force decays exponentially along the height of the channel. The effect of DEP forces on the concentration profile is studied. It is observed that, the concentration of colloidal particles at the electrodes edges is very less compared to elsewhere. Mixing of two colloidal suspensions due to diffusion is observed at the interface of the two suspensions. The improvement in mixing after applying the repulsive DEP forces on the colloidal suspension is observed. Most of the mixing takes place across the slant edges of the triangular electrodes. The effect of electrode pairs and the mixing length on degree of mixing efficiency are also observed.

PS Colloidal Particles Stabilized by Graphene Oxide

Langmuir ◽  
2011 ◽  
Vol 27 (3) ◽  
pp. 1186-1191 ◽  
Author(s):  
Xiaohui Song ◽  
Yongfang Yang ◽  
Jinchuan Liu ◽  
Hanying Zhao
Keyword(s):  
Graphene Oxide ◽  
Colloidal Particles

Tuning the oxygen functional groups in reduced graphene oxide papers to enhance the electromechanical actuation

RSC Advances ◽  
2015 ◽  
Vol 5 (83) ◽  
pp. 68052-68060 ◽  
Author(s):  
Ganaka G. Chandrakumara ◽  
Jin Shang ◽  
Ling Qiu ◽  
Xi-Ya Fang ◽  
Frank Antolasic ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Graphene Oxide ◽  
Theoretical Model ◽  
Reduced Graphene Oxide ◽  
Oxygen Content ◽  
Key Factors ◽  
Actuation Mechanism ◽  
Reduced Graphene ◽  
Electromechanical Actuation ◽  
Actuation Strain

Tuning oxygen content in rGO paper is found to enhance its actuation strain. The developed theoretical model and in-depth experimental investigation show that capacitance and stiffness are two key factors in the actuation mechanism of rGO papers.

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