Electric-field-induced aggregation in dilute colloidal suspensions

1990 ◽  
Vol 90 ◽  
pp. 17 ◽  
Author(s):  
Paul M. Adriani ◽  
Alice P. Gast
Keyword(s):  
Electric Field ◽  
Colloidal Suspensions ◽  
Induced Aggregation

scholarly journals Optical and X-ray scattering studies of the electric field-induced orientational order in colloidal suspensions of pigment nanorods

2018 ◽  
Vol 267 ◽  
pp. 286-296 ◽  
Author(s):  
Oleksandr Buluy ◽  
Natalie Aryasova ◽  
Oleksandr Tereshchenko ◽  
Yuriy Kurioz ◽  
Vassili Nazarenko ◽  
...  
Keyword(s):  
Electric Field ◽  
Orientational Order ◽  
Colloidal Suspensions ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

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.

scholarly journals New Generalized Viscosity Model for Non-Colloidal Suspensions and Emulsions

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 150
Author(s):  
Rajinder Pal
Keyword(s):  
Volume Fraction ◽  
Colloidal Suspensions ◽  
High Ratio ◽  
Solid Particles ◽  
Viscosity Model ◽  
Viscosity Data ◽  
Liquid Droplets ◽  
Newtonian Liquids ◽  
Liquid Suspensions ◽  
Induced Aggregation

The viscous behavior of solids-in-liquid suspensions and liquid-in-liquid emulsions of non-Brownian solid particles and liquid droplets dispersed in Newtonian liquids is thoroughly discussed and reviewed. The full concentration range of the dispersed particles/droplets is covered, that is, 0<ϕ<ϕm, where ϕ is the volume fraction of inclusions (particles or droplets) and ϕm is the maximum packing volume fraction of inclusions. The existing viscosity models for suspensions and emulsions are evaluated using a large pool of experimental viscosity data on suspensions and emulsions. A new generalized model for the viscosity of suspensions and emulsions is proposed and evaluated. The model takes into consideration the influence of shear-induced aggregation of particles and droplets. It also includes the effect of the droplet-to-matrix viscosity ratio λ on the viscosity of emulsions. In the limit of high ratio of droplet viscosity to matrix viscosity (λ→∞), the model reduces to the suspension viscosity model. The proposed model uncovers some important and novel characteristics of suspension systems rarely discussed heretofore in the literature. The model is validated using twenty sets of experimental viscosity data on solids-in-liquid suspensions and twenty-three sets of experimental viscosity data on liquid-in-liquid emulsions.

PHASE SEPARATION AND TURBIDITY OF ELECTRORHEOLOGICAL FLUIDS

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3093-3101 ◽  
Author(s):  
S. CUTILLAS ◽  
A. MEUNIER ◽  
E. LEMAIRE ◽  
G. BOSSIS ◽  
J. PERSELLO
Keyword(s):  
Electric Field ◽  
Silicone Oil ◽  
Average Length ◽  
Coupling Parameter ◽  
Electrorheological Fluids ◽  
Electrostatic Energy ◽  
Theoretical Interpretation ◽  
Debye Theory ◽  
Induced Aggregation ◽  
Kinetics Of

The turbidity of a suspension of silica particles in a silicone oil is studied in the presence of an electric field. We present experimental results which show a very strong attenuation of a laser beam when the electric field is switched on. We give a theoretical interpretation of these results with the help of a Rayleigh Gans Debye theory applied to cylinders. This model allows us to obtain the average length of the aggregates as a function of the coupling parameter λ, which is me ratio of the electrostatic energy to kT. These results agree with a theoretical prediction and also with the results of Monte-Carlo simulations. The kinetics of the beginning of field induced aggregation can be obtained from the change of the turbidity with time after the application of a voltage step.

MONODISPERSE COLLOIDAL SUSPENSIONS OF SILICA AND PMMA SPHERES AS MODEL ELECTRORHEOLOGICAL FLUIDS: A REAL-SPACE STUDY OF STRUCTURE FORMATION

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2328-2333 ◽  
Author(s):  
ANAND YETHIRAJ ◽  
ALFONS VAN BLAADEREN
Keyword(s):  
Electric Field ◽  
Structure Formation ◽  
Colloidal Particles ◽  
Intermediate Phase ◽  
Finite Size ◽  
Colloidal Suspensions ◽  
Real Space ◽  
Three Dimensions ◽  
Electrorheological Fluids ◽  
Crystal Formation

Colloidal particle coordinates in three dimensions can be obtained in 3D samples with a combination of the increased resolution and optical sectioning capabilities of confocal microscopy and fluorescently labeled model core-shell silica colloids. In this work we show how this capability can be used to analyze structure formation in electrorheological fluids on a quantitative basis. We find body-centered-tetragonal (BCT) crystals for colloidal particles in an electric field. Metastable sheet like structures were identified as an intermediate phase prior to BCT crystal formation. Due to finite-size effects induced by the electrode surface the sheets are not randomly oriented, but grow preferentially with a 60° tilt with respect to the electric field. Preliminary measurements indicate that flow-aligned sheets form under shear. Finally, we show that in the case that the ionic strength is very low, electric-field-induced dipolar interactions can be present in addition to long-range repulsions between the colloids leading to interesting metastable and equilibrium structures with possibilities for applications in photonic bandgap crystals as well as in model ER studies.

Sign in / Sign up

Export Citation Format

Share Document