Física Aplicada I, Universidad de Málaga, 29071 Málaga, Spain.
J Colloid Interface Sci. 2012 Dec 1;387(1):153-61. doi: 10.1016/j.jcis.2012.07.094. Epub 2012 Aug 9.
We analyze the influence of finite ion size effects in the response of a salt-free concentrated suspension of spherical particles to an oscillating electric field. Salt-free suspensions are just composed of charged colloidal particles and the added counterions released by the particles to the solution that counterbalance their surface charge. In the frequency domain, we study the dynamic electrophoretic mobility of the particles and the dielectric response of the suspension. We find that the Maxwell-Wagner-O'Konski process associated with the counterions condensation layer is enhanced for moderate to high particle charges, yielding an increment of the mobility for such frequencies. We also find that the increment of the mobility grows with ion size and particle charge. All these facts show the importance of including ion size effects in any extension attempting to improve standard electrokinetic models.
我们分析了有限离子尺寸效应对无盐浓悬浮球形颗粒对振荡电场响应的影响。无盐悬浮液仅由带电胶体颗粒和由颗粒释放到溶液中的抗衡离子组成，以平衡其表面电荷。在频域中，我们研究了颗粒的动态电泳迁移率和悬浮液的介电响应。我们发现，与抗衡离子凝聚层相关的 Maxwell-Wagner-O'Konski 过程在中等至高颗粒电荷下得到增强，从而导致此类频率下迁移率的增加。我们还发现，迁移率的增加随离子尺寸和颗粒电荷的增加而增加。所有这些事实都表明，在任何试图改进标准电动模型的扩展中，都必须考虑离子尺寸效应。
