ELECTROSTATIC INTERACTIONS IN COLLOIDAL SUSPENSIONS : TESTS OF PAIRWISE ADDITIVITY
ELECTROSTATIC INTERACTIONS IN COLLOIDAL SUSPENSIONS : TESTS OF PAIRWISE ADDITIVITY
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胶体悬浮液中的静电相互作用：成对可加性测试
DOI：
10.1002/aic.690370604
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发表时间：
1991
期刊：
影响因子：
3.7
通讯作者：
C. Radke
中科院分区：
文献类型：
--
作者：
Eric S. Reiner;C. Radke
双电层自由能的数值计算模型胶体悬浮液的带电，六角形包装的单分散圆柱体在对称的电解质溶液中使用泊松-玻尔兹曼方程。比较了两种径向对称胞元模型的能量估计值：一种是选择圆柱胞元的外边界，使近似模型中的粒子体积分数Φ与全点阵模型一致;另一种是选择胞元外边界的位置为点阵中最近邻间距的一半。计算的粒子体积分数范围从无限稀释到98%的最紧密堆积，离子强度（德拜长度与粒子半径的比值λ/a）从0.1到10.0，无量纲表面电位和电荷密度从0.1到10.0。
对近似只有在典型的粒子间距大于德拜长度时才有效。细胞模型的第一个实现证明是相当准确的，而第二个只是定性正确。粒子表面电荷密度或电位的大小对这些结论的影响很小。
The electrical double-layer free energy is computed numerically for a model colloidal suspension of charged, hexagonally-packed monodisperse cylinders in a symmetric electrolyte solution using the Poisson-Boltzmann equations. Comparison is made to the energies estimated from sums of pair interactions and from two versions of a radially-symmetric cell model: one in which the outer boundary of the cylindrical cell is chosen to make the particle volume fraction Φ in the approximate model agree with that of the full lattice and the other in which the position of the outer boundary is chosen as half the nearest neighbor separation in the lattice. Calculations are performed for ranges of particle volume fractions from infinite dilution to 98% of closest packing, ionic strengths (in terms of the ratio of Debye length to particle radius λ/a) from 0.1 to 10.0, and dimensionless surface potentials and charge densities from 0.1 to 10.0.
The pair approximation is valid only when typical interparticle spacings are greater than the Debye length. The first implementation of the cell model proves quite accurate, while the second is only qualitatively correct. The magnitude of particle surface charge density or potential has little effect on these conclusions.