軟性膠體之多孔層結構對其水力與電泳行為的影響

Influence of the Porous Layer Structure of a Soft Colloid on its Hydrodynamic and Electrophoretic Behaviors

周志浩(Chih-Hao Chou)

指導教授 ： 徐治平

國立臺灣大學/工學院/化學工程學研究所/博士(2012年)

https://doi.org/10.6342/NTU.2012.02349

摘要

本論文係以有限體積法，研究具表面多孔層之軟質膠體粒子在受一外加電場之作用而產生之電泳動行為。吾人延伸前人的成果將研究方向朝具非均質表面(層)結構的圓球形/超環形膠體粒子，討論該等粒子之表面(層)結構對其電泳行為之影響。探討的主題包括不同方向孔隙度對軟質膠體(膠羽)的流力行為之影響、超環形膠體粒子的電泳行為、具非均質表面(層)結構之圓球形軟質膠體粒子的電泳行為，及具非均質表面(層)表面結構之超環形軟質膠體粒子的電泳。在計算技巧上，由於低粒子表面電位及弱外加電場的假設條件，將相互偶合的電場及流場方程式線性化，因此可用疊加原理求解。
研究結果發現下列幾項因素對軟質膠體粒子的電泳速度有顯著的影響：多孔層固定電荷密度、多孔層阻力係數、多孔層均勻度、及多孔層之厚度等。研究結果顯示多孔層固定電荷密度高、多孔層阻力係數小、多孔層均勻度高、及多孔層之厚度較厚，對軟質膠體粒子之電泳動遷移率有提升的效果，且在前述多個因素中，多孔層固定電荷密度之高低會直接影響電泳動驅動力的大小，故其對膠體粒子電泳行為所產生的效應最為明顯。另外，當膠體粒子之電雙層厚度大時，表面(層)結構對其電泳行為之影響最為顯著。

關鍵字

電泳 ； 表面(層)結構 ； 超環形粒子 ； 軟質膠體 ； 固定電荷密度 ； 均勻度

並列摘要

The electrophoretic mobility of soft colloidal particles is investigated in this study for various types of problems by using finite volume method. For the present study, we consider the effect of surface (layer) structure on the electrophoresis behaviors of a soft colloid, and also extend the integrated soft (porous) particle to non-integrated one like the toroid. The analysis include 3D simulations of hydrodynamic drag on a nonhomogeneously structured permeable sphere and advective flow thereof, electrophoresis of an arbitrarily oriented toroid in an unbounded electrolyte solution, importance of the porous structure of a soft particle on its electrophoretic behavior, and electrophoresis of a soft toroid with exponential segment distribution in an unbounded electrolyte solution. Referring to the skill of calculation, the coupled flow field and electric field equations or so-called electrokintic equations can be linearized assuming the applied electric field is weak and the surface potential is low, and therefore, a superposition is used to solve problem.
We found that the particle mobility is affected by several factors, the fixed charge density of the porous layer, the drag (resistance) coefficient of the porous layer, the uniformity of the porous layer, and the thickness of the porous layer. Results reveal that when the fixed charge density is higher, the drag (resistance) coefficient is smaller, the porous layer is more uniform, or the porous layer is thicker, the electrophoresis mobility of a soft colloid will be enlarged. In addition, when the thickness of electric double layer is larger, the effect of surface (layer) structure on the electrophoresis behavior of a soft colloid will be more obvious.

並列關鍵字

Electrophoresis ； Surface (layer) structure ； Toroid ； Soft colloid ； Fixed charge density ； Uniformity

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