Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan.
Electrophoresis. 2011 Nov;32(21):3053-61. doi: 10.1002/elps.201100193. Epub 2011 Oct 11.
The influence of the physical properties of the membrane layer of a soft particle, which comprises a rigid core and a porous membrane layer, on its electrophoretic behavior, is investigated. Because that influence was almost always neglected in the previous studies, the corresponding results can be unrealistic. The applicability of the model proposed is verified by the available theoretical and experimental results. The electrophoretic mobility of the particle under various conditions is simulated through varying the dielectric constant, the thickness, and the drag coefficient of the membrane layer, and the bulk ionic concentration. We show that under typical conditions, the deviation in the electrophoretic mobility arising from assuming that the dielectric constant of the membrane layer is the same as that of the bulk liquid phase can be in the order of 50%. In addition, the thicker the membrane layer and/or the higher the bulk ionic concentration, the larger the deviation. If the surface of the core of the particle is charged, as in the case of inorganic particles covered by an artificial membrane layer, the deviation at constant core surface potential is larger than that under other types of charged conditions. However, if the surface of the core is uncharged, as in the case of biocolloids, then that deviation becomes negligible. These findings are of fundamental significance to theoreticians in their analysis on the electrokinetic behaviors of soft particles, and to experimentalists in the interpretation of their data.
研究了由刚性核和多孔膜层组成的软粒子的膜层的物理性质对其电泳行为的影响。由于在以前的研究中几乎总是忽略了这种影响，因此相应的结果可能不现实。通过可用的理论和实验结果验证了所提出模型的适用性。通过改变介电常数、膜层的厚度和阻力系数以及本体离子浓度，模拟了各种条件下粒子的电泳迁移率。结果表明，在典型条件下，假设膜层的介电常数与本体液相相同所引起的电泳迁移率偏差可能在 50%左右。此外，膜层越厚和/或本体离子浓度越高，偏差越大。如果粒子的核表面带电，例如被人工膜层覆盖的无机粒子，则在恒定核表面电势下的偏差大于其他类型的带电条件下的偏差。但是，如果核表面不带电，例如生物胶体，则该偏差可以忽略不计。这些发现对理论家在分析软粒子的电动行为以及实验者在解释其数据方面具有重要的理论意义。
