TY - JOUR

T1 - Electrostatic interactions of a string-like particle with a charged plate

AU - Tsao, Heng Kwong

N1 - Funding Information:
This research is supported by National Council of Science of Taiwan under Grant No. NSC 86-2621-E-008-012-T.

PY - 1998/6/15

Y1 - 1998/6/15

N2 - The electrostatic interactions for a string-like particle with a charged plate are investigated on the basis of the Poisson-Boltzmann equation under the Debye-Huckel approximation. During the interaction, the plate is assumed to be with constant surface potential or constant surface charge density. The interaction energy is found to consist of two terms. The first term is simply the result of Gouy-Chapman theory, and it is the work required to insert a ghost particle into the undisturbed electric field established by the electrolyte solution and the charged wall. The second term represents the interaction between the particle and its image with respect to the plate. The interaction energy, which is nondimensionalized by QΨ(p0), depends on the distance between the particle and the plate, the contour length, and the orientation of the particle. Q is the total charge carried by the particle, and Ψ(p0) is the undisturbed surface potential. At short distance, the relative importance of the image to the plate contribution grows with increasing KQ/Ψ(p0). For QΨ(p0) > 0, the interaction can become attractive if KQ/Ψ(p0) is large enough. Here κ-1 is the Debye screening length. The results have been applied to fiber- and ring-like particles. Analytical expressions are obtained in some limiting cases. The free energy contributions due to the plate and the image are maxima when the plane containing the fiber or the ring is perpendicular to the wall. The effect of nonuniform charge distribution of the fiber has also been discussed.

AB - The electrostatic interactions for a string-like particle with a charged plate are investigated on the basis of the Poisson-Boltzmann equation under the Debye-Huckel approximation. During the interaction, the plate is assumed to be with constant surface potential or constant surface charge density. The interaction energy is found to consist of two terms. The first term is simply the result of Gouy-Chapman theory, and it is the work required to insert a ghost particle into the undisturbed electric field established by the electrolyte solution and the charged wall. The second term represents the interaction between the particle and its image with respect to the plate. The interaction energy, which is nondimensionalized by QΨ(p0), depends on the distance between the particle and the plate, the contour length, and the orientation of the particle. Q is the total charge carried by the particle, and Ψ(p0) is the undisturbed surface potential. At short distance, the relative importance of the image to the plate contribution grows with increasing KQ/Ψ(p0). For QΨ(p0) > 0, the interaction can become attractive if KQ/Ψ(p0) is large enough. Here κ-1 is the Debye screening length. The results have been applied to fiber- and ring-like particles. Analytical expressions are obtained in some limiting cases. The free energy contributions due to the plate and the image are maxima when the plane containing the fiber or the ring is perpendicular to the wall. The effect of nonuniform charge distribution of the fiber has also been discussed.

KW - Electrostatic interactions

KW - Fiber

KW - Image method

KW - Poisson-Boltzmann equation

KW - Ring particle

UR - http://www.scopus.com/inward/record.url?scp=0032527032&partnerID=8YFLogxK

U2 - 10.1006/jcis.1998.5471

DO - 10.1006/jcis.1998.5471

M3 - 期刊論文

AN - SCOPUS:0032527032

VL - 202

SP - 527

EP - 540

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 0021-9797

IS - 2

ER -