TY - JOUR

T1 - Dynamic mobility of two spherical particles with thick double layers

AU - Ennis, J.

AU - Shugai, Alexander A.

AU - Carnie, Steven L.

PY - 2000/3/1

Y1 - 2000/3/1

N2 - The dynamic electrophoretic mobility of a pair of nearby spherical particles is analyzed in the case when the thickness of the electrical double layer around each particle is comparable to the particle radius. By means of an integral reciprocal relation, a formal expression is obtained for the force and torque on N spheres subject to an oscillating electric field which may be spatially varying. Upon linearizing in the surface potential, this expression is shown to depend upon a set of purely hydrodynamic problems involving N neutral spheres, the calculation of the electric field around N neutral spheres, and the equilibrium charge distribution around N charged spheres. In the case of a single particle, the known analytic formula for the dynamic mobility is recovered. For a pair of identical particles, the dynamic mobility is calculated numerically, using known solutions to the required subproblems. An analytical expression for the mobility of a pair of widely separated spheres is also obtained by a method of reflections, and this is in excellent agreement with the numerical results outside the range of double layer overlap. (C) 2000 Academic Press.

AB - The dynamic electrophoretic mobility of a pair of nearby spherical particles is analyzed in the case when the thickness of the electrical double layer around each particle is comparable to the particle radius. By means of an integral reciprocal relation, a formal expression is obtained for the force and torque on N spheres subject to an oscillating electric field which may be spatially varying. Upon linearizing in the surface potential, this expression is shown to depend upon a set of purely hydrodynamic problems involving N neutral spheres, the calculation of the electric field around N neutral spheres, and the equilibrium charge distribution around N charged spheres. In the case of a single particle, the known analytic formula for the dynamic mobility is recovered. For a pair of identical particles, the dynamic mobility is calculated numerically, using known solutions to the required subproblems. An analytical expression for the mobility of a pair of widely separated spheres is also obtained by a method of reflections, and this is in excellent agreement with the numerical results outside the range of double layer overlap. (C) 2000 Academic Press.

KW - Dynamic mobility

KW - Electroacoustic

KW - Particle interactions

KW - Thick double layers

UR - http://www.scopus.com/inward/record.url?scp=0034051461&partnerID=8YFLogxK

U2 - 10.1006/jcis.1999.6587

DO - 10.1006/jcis.1999.6587

M3 - Article

SN - 0021-9797

VL - 223

SP - 21

EP - 36

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

IS - 1

ER -