橢球在充滿無鹽電解質溶液之球型孔洞內之電泳

Abstract

本論文以有限元素分析法研究一橢球形粒子在充滿無鹽電解質溶液之球型孔洞中的任意位置電泳行為的影響，其中，無鹽電解質溶液即為溶液相中僅包含從粒子上官能基解離出的反離子而不含其它鹽類介質。 數值模擬的結果顯示，對粒子電泳的定性行為有重大影響的參數如下：粒子表面的總帶電量、分散在溶液當中的反離子價數、球型孔洞與粒子之間的相對大小、橢球粒子的縱橫軸長度比、粒子在球型孔洞中的位置。許多有趣的結果在此論文中被觀察到，例如：當粒子表面總帶電量固定時，大致上電泳動度的大小排序為：長橢球＞球＞扁橢球；反離子凝聚效應導致電泳動度依反離子價數的增加而遞減的情形；電泳動度對橢球粒子的縱橫軸長度比做圖出現極大值。

The electrophoretic behavior of a spheroid at an arbitrary position in a spherical cavity is analyzed numerically under a salt-free condition, that is, the liquid phase contains only counterions which come from the dissociation of the functional groups of particle. The influences of the key parameters of the system under consideration, including the total amount of surface charge on the particle, the valence of the counterion, the relative size of the cavity, the aspect ratio of the particle and its position in the cavity. Several interesting results were observed. For example, if the total amount of surface charge is fixed, the magnitude of the electrophoretic mobility for various types of particle generally ranks as prolate>sphere>oblate. The effect of counterion condensation yields a small value of electrophoretic mobility in the case of high valence of the counterions. In addition, it exhibits a local maximum in the electrophoretic mobility as the aspect ratio of the particle varies.