Kuo J, Keh HJ
Department of Chemical Engineering, National Taiwan University, Taipei, 106-17, Taiwan, Republic of China
J Colloid Interface Sci. 1997 Nov 15;195(2):353-67. doi: 10.1006/jcis.1997.5144.
The effects of adsorbed polymer on the slow motion of two spherical particles along the line of their centers are examined semianalytically. The particles may have unequal radii, and their surface polymer layers are allowed to differ in characteristics. The surface polymer layer on each particle is assumed to be thin relative to the radius of the particle and to the surface-to-surface distance between the particles. A method of matched asymptotic expansions in small parameters lambdai (where i = 1 and 2) combined with a boundary collocation technique is used to find the solution for the creeping flow field within and outside the adsorbed polymer layers, where lambdai is the ratio of the polymer-layer length scale to the radius of particle i. The results for the hydrodynamic forces exerted on the particles in a resistance problem and for the particle velocities in a mobility problem are expressed in terms of the effective hydrodynamic thicknesses (Li) of the polymer layers, which are accurate to O(lambdai2). The O(lambdai) term for Li normalized by its value in the absence of the other particle is found to be independent of the polymer segment distribution, the hydrodynamic interactions among the segments, and the volume fraction of the segments. The O(lambdai2) term for Li, however, is a sensitive function of the polymer segment distribution and the volume fraction of the segments. In general, the effects of particle interactions on the motion of polymer-coated particles can be quite significant, especially when the particles are moving in the opposite directions. Copyright 1997 Academic Press. Copyright 1997Academic Press
通过半解析方法研究了吸附聚合物对两个球形颗粒沿其中心连线缓慢运动的影响。颗粒半径可能不等，且其表面聚合物层的特性也可能不同。假定每个颗粒上的表面聚合物层相对于颗粒半径和颗粒间的表面间距较薄。采用小参数λi（其中i = 1和2）的匹配渐近展开法与边界配置技术相结合，来求解吸附聚合物层内外的蠕动流场，其中λi是聚合物层长度尺度与颗粒i半径的比值。在阻力问题中作用于颗粒的流体动力以及在迁移率问题中颗粒速度的结果，用聚合物层的有效流体动力厚度（Li）表示，其精度为O(λi2)。发现Li相对于在不存在另一个颗粒时其值的归一化O(λi)项与聚合物链段分布、链段间的流体动力相互作用以及链段的体积分数无关。然而，Li的O(λi2)项是聚合物链段分布和链段体积分数的敏感函数。一般来说，颗粒相互作用对聚合物包覆颗粒运动的影响可能相当显著，尤其是当颗粒沿相反方向运动时。版权所有1997年学术出版社。版权所有1997年学术出版社
