陳立仁臺灣大學：化學工程學研究所葉松峰Yeh, Sung-FengSung-FengYeh2007-11-262018-06-282007-11-262018-06-282006http://ntur.lib.ntu.edu.tw//handle/246246/52302對於一個三相（α,β,γ）共存的平衡系統中，各平衡相密度關係為ργ＞ρβ＞ρα。極少量的中間相（β）可能以非濕透、部分濕透或是完全濕透的形式存在於上（α）、下（γ）兩相之間。而由部分濕透與非濕透（或是完全濕透）之間的互相轉變，稱為濕透轉變。現今我們所關心的是三臨界點附近的濕透行為，以及是否有濕透轉變的發生。通常可藉由系統參數的改變，如溫度、壓力、鹽類濃度及界面活性劑強度等，來逼近三臨界點。在多成分的溶液中，三臨界點定義為三共存的液相同時轉變為相同一相之臨界點。因此，本實驗的一部份是利用水＋油＋界面活性劑系統中油碳鍊長度的改變來逼近三臨界點。而結果發現，隨著油碳鏈的減少，可成功逼近三臨界點。 在本實驗三成份的系統中，主要研究的系統為“water＋alkane（octane、nonane、decane） +C4E1”，其中所用的C4E1（ethylene glycol n-butyl ether）屬於非離子型的界面活性劑CiEj。CiEj為CH3(CH2)i-1(OCH2CH2)jOH之縮寫，其中i代表非極性碳氫鏈長度，而j代表的是極性乙烯氧基的長度。我們利用懸附液滴張力儀所測得的界/表面張力值並計算濕透係數來判斷系統的濕透行為。結果得知，當系統由下臨界溫度升至上臨界溫度時，我們可觀察到此三個系統皆存在兩個濕透轉變（完全濕透→部分濕透→完全濕透）。此行為符合Cahn（J. Chem. Phys., 66, 3667, 1977）在1977年提出的臨界濕透理論：針對一個三相共存的系統，當溫度相當接近其中兩相的臨界溫度時，必能觀察到濕透轉變。 此外，在此論文的另一部份，我們還研究了兩成份系統：“water＋CiPj（C3P1、C3P2、C4P1、C4P2、C4P3）”。其中CiPj（n-alkyl propylene glycol ethers）為另一種親水端為丙烯氧基之界面活性劑，也屬於非離子型的界面活性劑。CiPj為CH3(CH2)i-1(OCH2CH(CH3))jOH之縮寫，其中i代表非極性碳氫鏈長度，而j代表的是極性丙烯氧基的長度。我們想要了解在不同的界面活性劑下，隨著溫度逐漸逼近系統的臨界溫度是否會有濕透轉變發生並加以討論。結果發現到，在我們實驗的操作溫度範圍下（10~40℃），C3P1系統在可實驗溫度範圍下（35-40℃）皆呈現完全濕透外，C3P2系統隨著溫度的下降逼近臨界點，β相會有濕透轉變發生（部份濕透→完全濕透），也符合臨界濕透理論。而water＋C4P3、water＋C4P2、water＋C4P1三個系統皆呈現部份濕透。此外，本論文也探討界面活性劑碳氫鏈長度和丙烯氧基的長度對親疏水性和濕透行為的影響。For a three-phase (α,β,γ) coexisting equilibrium system, the densities of these three phase are in the order ργ＞ρβ＞ρα and the middle phase (β) may exist in the form of non-wetting, partial wetting or complete wetting between the upper（α）and lower（γ）phases. The transition from a partial wetting region to a non-wetting (or a complete wetting) region is called a wetting transition. Consequently, what we are concerned about is the wetting behavior near the tricritical point and whether there are wetting transitions or not. By adjusting the system parameters, such as temperature, pressure, salt concentration and kinds of surfactants, we can make the system approach to its tricritical point. In a multi-component liquid mixture, a tricritical point (TCP) is defined as a point at which three coexisting liquid phases become simultaneously single phase. Thus, in this study, we try to approach the tricritical point by changing the oil-chain length of the system “water +oil +surfactant”. With the decrease of the oil chain length, we can successfully approach the tricritical point. In the study, the main three-component systems are “water＋alkane（octane、nonane、decane）＋C4E1” and pendant bubble/drop tensionmetry was applied to measure interfacial/surface tensions and calculate the wetting coefficients to judge the wetting behaviors of the systems. The symbol C4E1（ethylene glycol n-butyl ether） is a nonionic surfactant CiEj and CiEj is the abbreviation of CH3(CH2)i-1(OCH2CH2)jOH. From the conclusion of the study, when rising temperature from the lower critical point to upper critical point, we can find both two wetting transitions: complete wetting→partial wetting→complete wetting. Importantly, these behaviors obey Cahn’s theory（J. Chem. Phys., 66, 3667, 1977）, which asserts that for a three-phase coexisting system, complete wetting should be observed near the critical temperature. Besides, we also experiment on the two-component systems “water＋CiPj（C3P1、C3P2、C4P1、C4P2、C4P3）”. CiPj is another nonionic surfactant which is the abbreviation of CH3(CH2)i-1(OCH2CH(CH3))jOH. From the systems, we want to understand that whether there are wetting transitions or not by changing the temperature with different surfactants. In the conclusion, we can find that there is a wetting transition (partial wetting→complete wetting ) in the system “water＋C3P2” which also obey Cahn’s critical wetting theory and the system “water＋C3P1” expresses complete wetting in our operating temperature range (10~40℃). However, three systems “water＋C4P3”, “water＋C4P2”and “water＋C4P1” all express partial wetting in the range from 10~40℃. Besides, we also discuss the effects of the hydrocarbon chain length and oxypropylene group length for wetting behaviors.表目錄…………………………………………………………………Ⅰ 圖目錄…………………………………………………………………Ⅱ 第一章 簡介…………………………………………………………1 第二章 理論部分……………………………………………………5 一、水＋油＋界面活性劑系統之相行為…..…………………….5 二、界/表面張力與濕透為…………………..……………………8 三、逼近三臨界點…………………………………………………11 四、懸附液滴法測張力之原理……………………………………13 第三章 實驗部分………………………………………………….19 一、實驗藥品………………………………………………………19 二、實驗儀器………………………………………………………20 三、實驗方法………………………………………………………22 第四章 結果與討論……………………………………………….27 第五章 結論……………………………………………………….38 參考文獻...……………………………………………………….40 附錄………...…………………………………………………….1031373766 bytesapplication/pdfen-US濕透行為濕透轉變界面活性劑wetting behaviorwetting transitionsurfactantthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/52302/1/ntu-95-R93524029-1.pdf