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標題: | 軟球粒子之擴散泳現象探討 Diffusiophoretic Motion of an Isolated and Suspended Charged Soft Particles |
作者: | Wen-Chun Chang 張雯鈞 |
指導教授: | 李克強(Eric Lee) |
關鍵字: | 擴散泳,電雙層極化效應,電泳效應,軟球,懸浮系統, diffusiophoretic motion,chemiphoresis component,electrophoresis component,charged soft particle,suspension system, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 本研究分探討高電位軟球粒子於電解質溶液中的擴散泳現象,針對化學泳成分與電泳成分效應驅動研究,並分為單顆粒子與密集系統詳盡討論,共分成三個章節。
首先,研究發現電泳成分效應作用方向會受β factor影響,若陰陽離子擴散係數相差愈大,則給予系統的電泳效應驅動力更強。此外,溶液電解質濃度(κa)會大幅影響擴散泳動度,甚至左右粒子的泳動方向,而此起因為化學泳效應與電泳效應之角力,因在NaCl溶液中,化學泳效應與電泳效應分別會使粒子往不同方向泳動,一般情況下,粒子泳動以電泳效應驅動為主,因此會使粒子往低濃度方向泳動;而在κa極大時,硬球核之化學泳效應會十分顯著,兩者拉鋸下使粒子速度下降,甚至發生速度反轉的反物理直覺之現象。 另外,可藉由調整硬球核之比例來協調化學泳效應之比例,並控制軟球粒子在高離子濃度溶液中的泳動方向。而調整軟球層的穿透度與硬球核帶電量,也會使軟球粒子更加趨近硬球粒子的泳動表現。而當軟球粒子處於懸浮系統時,密集度愈大的系統粒子之間的距離愈短,其外圍離子分布更加緊密,施加濃度場後會產生較大驅動力,使軟球粒子泳動度上升。總而言之,本研究可適切地預測軟球粒子之擴散泳現象,將之應用於藥物輸送與分離程序。 Diffusiophoresis refers to the particle motion in the solution in response to a superimposed concentration gradient of solutes surrounding it. In this study, diffusiophoresis of a charged soft particle is investigated theoretically. We found that the direction of the soft particle is dependent on difference diffusivity of cation and anions, β factor. In particular, the direction of electrophoresis component is the same as the sign of β factor. Moreover, the direction of particle change at various ionic strengthen of electrolyte solution (κa), due to the competition between electrophoresis component and chemiphoresis component. For example, the chemiphoresis component dominates at large κa value, or very thin double layer, so the direction of particle reverse in NaCl solution. In this study, the velocity reversal of soft particle with a high ratio of rigid core is observed at high κa value in NaCl solution. It is attributed to the dominant of the electrophoresis component of the rigid core. Also, the mobility of soft particle tends to be closer to that of a rigid particle with the appropriate selection of the permittivity of the soft layer and the zeta potential of the rigid core. The higher the volume fraction ratio is, the higher the mobility. This is due to the ionic clouds get dense between the soft particle and neighboring particles, resulting in the increasing of the driving force. The current study provides important fundamental information about the diffusiophoretic behavior of charged soft particle, which is critical for the application of drug delivery and separation process involving charged soft particles such as SPB and core-shell nanoparticles. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/74671 |
DOI: | 10.6342/NTU201902007 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學工程學系 |
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