Comparison Study on Temperature Dependence of the Interfacial Tension of n-Alkane Water and n-Alcohol Water Two Binary Systems

A pendant drop shape technique, enhanced by video-image digitization, was applied to measure the interfacial tension for n-alkanewater and n-alcoholwater of 69 carbon atoms binary systems at the temperature of 293.2 to 343.2 K. The experimental results of interfacial tension measured by this method were correlated for each binary system as a function of temperature. For n-alkanewater binary system, it could be seen from the results that the interfacial tension decreases with increasing temperature. Further, for each n-alkanewater binary system investigated, all data points determined in the present investigation fall approximately on a straight line, that is, the temperature coefficients of the interfacial tension are uniformly negative. For n-alcoholwater binary system, results demonstrate that all gamma T curves present parabolic profiles, that is, the interfacial tension first increases with increasing temperature, then goes through a maximum and eventually decreases with increasing temperature. Moreover, the temperature at which the maximum of the interfacial tension occurs also increases with the number of carbon atoms in the alcoholic molecular chain. The agreement between the values by this method and those from the literature is fairly good.