我們實驗主要探討一微米大小的膠體球在有著氯化鈉溶液(葡萄糖溶液)的濃度梯度微通道中的動力學行為。實驗裝置由微通道連結了兩個槽：其中一個槽注滿了氯化鈉溶液(葡萄糖溶液)，另外一個則是注滿去離子水。又兩邊槽的濃度不同，因此離子(分子)會從高濃度擴散到低濃度，所以會在微通道內建立起濃度梯度。我們藉由顯微鏡記錄膠體球位置隨時間的變化，因此就可以量測出膠體球在氯化鈉溶液(葡萄糖溶液)濃度梯度下的平均速度，然而我們發現膠體球在此兩溶液的運動方向相反。此外我們也發現到膠體球在氯化鈉溶液中，膠體球的速度正比氯化鈉溶液濃度開方根，而這符合了由Debye-Huckel的理論為基礎出發所推出的關係式。最後我們也把結果代入了Deryagin的團隊所提出來的理論，結果發現表面電荷隨著氯化鈉的濃度上升而上升，而這也符合了由Prieve的團隊所做出的實驗結果。 In this thesis we investigate dynamical properties of 1 micrometer colloids placed in a narrow channel which is filled with a sodium chlorine solution and a glucose solution with a concentration gradient. Our device contains two reservoirs: one contains a NaCl solution, and the other is pure water. They are connected by a narrow channel of 60 micrometer depth and 0.5 mm in width. Because of the different NaCl/glucose concentration in the reservoirs, the ions of NaCl and molecules of glucose would diffuse from the high concentration reservoir to the low-concentration one, and a concentration gradient set up. By recording the motion of colloids under a microscopic, we study the colloids random motion and average flux induced by concentration of the NaCl. However, we find the the direction of the migration of the colloids in the NaCl solution are very different to be compared in the glucose solution. The colloids in the NaCl solution move from the higher concentration to the lower one, and the opposite direction occur in the glucose solution. We find that the velocity of colloid is proportional to square root of concentration in dilute region which is consistent with the derivation of the relation between the concentrations and the velocities in dilute concentration based on Debye-Huckel theory. Furthermore, we compare the experimental result with the theory proposed by Deryagin and co-workers, the surface charges increase with the concentration of the electrolyte solutes increasing.
