| Summary: | 博士 === 國立臺灣大學 === 化學工程學研究所 === 99 === In this study, we investigate the phase behavior and the wetting behavior of the ternary water + oil + nonionic surfactant system. The oils are n-alkanes and the nonionic surfactants are CiPj. The symbol CiPj is the abbreviation of a propylene glycol ether CH3(CH2)i-1(OCH2CH(CH3))jOH. There are three-liquid-phase- coexisting regions in water + decane + C3P1, water + dodecane + C3P1, water + tetradecane + C3P1, water + hexadecane + C3P1, water + dodecane + C3P2, water + tetradecane + C3P2, and water + hexadecane + C3P2 systems. Experiments of fish-shaped phase diagrams for these seven systems under atmospheric pressure were performed at constant water/n-alkane weight ratio (1/1) to locate the critical end points. The ternary system of the alkane with the longer carbon chain length has the higher upper and lower critical solution temperatures and the larger three-liquid-coexisting temperature window in the fish-shaped phase diagram. The upper and lower critical solution temperatures are lower in these systems with larger j number of C3Pj. Precise liquid-liquid equilibrium data of mixtures for six ternary systems water + alkane (dodecane, tetradencane, and hexadecane) + C3Pj (j=1 or 2) under atmospheric pressure were determined by using gas chromatography. The evolution of phase behavior of the ternary water + n-alkane + C3Pj system as a function of temperature is qualitatively consistent with that of the water + oil + CiEj system. The experimental liquid-liquid equilibrium data were successfully correlated with the NRTL model. We use pedant drop method to measure the interfacial tensions and investigate the wetting behavior of four ternary systems, water + dodecane + C3P1, water + tetradecane + C3P1, water + hexadecane + C3P1, and water + hexadecane + C3P2 system. In these ternary systems, the middle surfactant-rich phase exhibits complete wetting in the temperature window of the three-liquid-phase-coexisting region.
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