單一多孔球擴散泳之電泳成分效應暨離子液體溶液中之液滴電泳現象探討

Diffusiophoresis of a Highly Charged Porous Particle Induced by Diffusion Potential and Electrophoresis of a Liquid Droplet in the Ionic Liquid Solutions

蔡善琪(Shan Chi Tsai)

指導教授 ： 李克強

國立臺灣大學/工學院/化學工程學研究所/博士(2019年)

https://doi.org/10.6342/NTU201902023

摘要

本研究分為兩部份，探討兩種重要的電動力學現象。第一部份研討高電位多孔粒子於電解質溶液中的擴散泳現象，並且針對電泳成分效應驅動做了詳盡研究。第二部分則是研討單一液滴於離子液體溶液中的電泳現象。

第一部份的研究發現高穿透度多孔粒子的擴散泳動度會非常高，穿透度若差十倍，擴散泳動度可以差到二到三個數量級。並且在特定區域，化學泳效應會逐漸消失，而粒子泳動以電泳效應驅動為主。而極化效應以及反離子凝聚效應有可能造成高帶電粒子比低帶電粒子泳動度更慢的反物理直覺之現象。在本研究也發現H2CO3十分適合用於擴散泳現象，可以給予系統的電泳效應驅動力強，並且多孔球模型可以用於模擬多種生物聚電解質。總的來說，本研究可適切地預測生物聚電解質之擴散泳現象，將之應用於生醫工程程序。

第二部分則是單一液滴於離子液體溶液中的電泳現象。離子液體近年，因其多項優勢特質，被視為應用廣泛的綠色溶劑。然而直至目前為止，仍沒有人對於離子液體溶液中的液滴電泳系統進行研討。因此我們進行了詳盡的研究，而影響此系統的參數主要有四個，第一：離子有效體積，考慮了體積後，粒子表面的電荷量才可以符合真實物理系統。而研究結果顯示離子體積越大，泳動度越快。第二：離子間交互作用力特徵長度，δc，可以合理預測特殊且真實的物理現象：電位反轉以及泳動度反轉。

第三：內外黏度比，σ，內外黏度比大會使泳動度下降，反之亦然。第四：表面電位，ζ，在同時考慮離子體積以及離子間交互作用力時，泳動度會隨電位增加，有一個先升後降的趨勢，與物理直覺不同。綜上所述，可以發現離子液體溶液系統與傳統電解質溶液系統十分不同，有許多有趣的現象，無論在實驗上或理論預測上均可以看到。本研究利用理論模擬的方式預測此有趣且應用廣泛的系統，可做為學界與工業界進一步探討與應用的基礎。

關鍵字

電泳 ； 擴散泳 ； 電雙層極化效應 ； 電泳效應 ； 離子液體 ； 液滴 ； 多孔球

並列摘要

The electrokinetic behavior including diffusiophoresis of a porous particle in dilute electrolyte system and electrophoresis of droplet in ionic liquid solution is investigated in this study.

The first part is about diffusiophoresis of a charged porous particle is investigated theoretically in this study, focusing on the diffusiophoretic motion resulted from the diffusion potential induced by the distinct diffusivities of electrolyte ions in the suspension. In this study, we found that huge increase of particle velocity is observed for highly or extremely porous particles in a carbonic acid electrolyte solution, with λa=0.1 or 0.2 there. More than three orders of magnitude increase in particle diffusiophoretic mobility is predicted under some circumstances, should the permeability of the particle increases by ten-fold.

The electrophoresis component dominates at large κa value, or very thin double layer. The chemiphoresis component diminishes there, on the other hand, due to the strong counterion condensation by the double layer suppression effect. Local minima are observed in mobility profiles expressed as a function of κa for κa values around unity. This is attributed to the motion-deterring double layer polarization effect. The study exhibits the powerful potential of utilizing electrolyte solution with large diffusion potential, such as the carbonic acid solution studied here, to drive the particle in diffusiophoretic motion.

The second part is about electrophoresis of liquid droplets in electrolyte solutions containing ionic liquids.The scope of liquid droplets here covers over microemulsion, nanoemulsion, and micelles as well, which is regarded as a droplet with smaller size. Hence, the results are applicable to micelle electrophoresis in general as well.
We found that the electrophoresis of droplet in electrolyte solutions containing ionic liquids is fundamentally different from that in the conventional electrolyte solution. Because the size of the common electrolyte is much smaller than that of the ionic liquid, and the electrostatic interaction between ions is more complicated with ionic liquid in the electrolyte solution. As a result, a modified Poisson-Boltzmann equation and a modified Nernst-Planck equation considering the steric volume effect and the complicated electrostatic interaction between ions are adopted to describe the real system. Unique behaviors pertinent to ionic liquid systems are unveiled, such as the overscreening and the reversal of the electrophoretic mobility.

並列關鍵字

Electrophoresis ； Diffusiophoresis ； Double layer ； Double layer polarization ； ionic liquid ； Droplet ； Porous particle

參考文獻

1. Lechlitner, L. R.; Annunziata, O., Macromolecule diffusiophoresis induced by concentration gradients of aqueous osmolytes. Langmuir 2018, 34 (32), 9525-9531.

2. Annunziata, O.; Buzatu, D.; Albright, J. G., Protein diffusiophoresis and salt osmotic diffusion in aqueous solutions. The Journal of Physical Chemistry B 2012, 116 (42), 12694-12705.

3. McAfee, M. S.; Zhang, H.; Annunziata, O., Amplification of salt-induced polymer diffusiophoresis by increasing salting-out strength. Langmuir 2014, 30 (41), 12210-12219.

4. Yadav, V.; Freedman, J. D.; Grinstaff, M.; Sen, A., Bone-crack detection, targeting, and repair using ion gradients. Angewandte Chemie 2013, 52 (42), 10997-1001.

5. Hartman, S. V.; Božič, B.; Derganc, J., Migration of blood cells and phospholipid vesicles induced by concentration gradients in microcavities. New biotechnology 2018, 47, 60-66.