Dihedral Angle of Lens and Interfacial Tension of Air/Long Chain Alcohol/Water Systems

Abstract

The dihedral angle of an alcohol lens at the air/water interface and the three kinds of interfacial tensions of air/1-octanol/water and air/1-decanol/water systems have been measured as a function of temperature from 288.15 to 313.15 K at 2.5 K intervals under atmospheric pressure. In order to measure a dihedral angle, the new experimental apparatus was constructed and the new procedure was adopted. By comparing the dihedral angles measured with those calculated by applying Neumann's relations to the interfacial tension values, it was concluded that the dihedral angle measurement was performed with a satisfactory accuracy. The properties of the interfacial film and also the occurrence of the intruding of water phase on the air/alcohol interface were discussed.

Interfacial tension studies of crown ethers at air/water and hexane/water interfaces

“…Interfacial tension σ of 18-crown-6 and dicyclohexano-18-crown-6 at the air/water interface were measured by home made drop volume tensiometer [19] and those at hexane/water interface were measured by home made pendant drop tensiometer [20,21] at various concentrations and at 25.0 ± 0.1 • C. The estimated experimental error of σ was within ±0.05 mN/m. The equilibrium values of σ at air/water and hexane/water interfaces were obtained respectively after about 30 and 60 min later when the hanging drops were formed at the glass capillary tip.…”

Thermodynamics of Formation of and Adsorption at Interfaces with a Floating Lens

“…[9] and [10] simultaneously and therefore is purely algebraic, and the other is to introduce undetermined multipliers (25). We employ the latter because it has been reported that it offers distinct physical meanings to the undetermined multipliers (25 [11] where the superscript indicates that a quantity with is the surface excess one introduced in Eq. [4] and is defined by…”

“…[29] is reduced to Eq. [11] if v ,␥ is chosen to be zero. Now it is recognized that employing T, p ␣ , p ␤ , p ␥ , 4 , .…”

“…In our previous papers, the new apparatus and procedure for dihedral angle measurements have been shown to be very successful (11), and the state and phase transition of the interfacial films, the wetting behavior, the intruding phenomena, and the mutual relation among them have been discussed thoroughly with respect to the air/long-chain alcohol/water systems with a floating alcohol lens (12). In the thermodynamic analysis of the experimental interfacial tension data, however, only the resulting equations have been used without description of the detail formulation and convention employed.…”

Wetting Behavior of Mixtures of Water and Nonionic Polyoxyethylene Alcohol

“…This finding is consistent with that of Yeh et al, 17 which demonstrated that σ Rβ (n-C 6 E 0 ) > σ Rβ (n-C 5 E 0 ) > σ Rβ (n-C 4 E 0 ) and σ Rβ (n-C 5 E 0 ) > σ Rβ (2-C 5 E 0 ) > σ Rβ (t-C 5 E 0 ). It was suggested 15,16 that the longer hydrocarbon chains interact more strongly than the shorter ones in the alcohol-rich phase, and the transfer of alcohol molecules from bulk phase to the airliquid interface is energetically unfavorable for longer chain alcohols. Thus the iso-C 4 E 0 + water system provides lower surface tension σ Rβ due to its shorter "effective" chain length.…”