Tohru Inoue, Miyako Matsuda, Y. Nibu
Feb 8, 2001
Citations
0
Influential Citations
27
Citations
Journal
Langmuir
Abstract
The phase behavior of heptaethylene glycol dodecyl ether (C12E7) and its aqueous mixture was investigated by means of differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy in the temperature range from −20 to 70 °C. Phase boundaries among various phases including mesomorphic phases were determined on the basis of DSC thermograms, from which the binary phase diagram of this mixture system was constructed. According to the phase diagram, the mixture with the composition of 31 wt % H2O exhibits the following phase sequence with increasing temperature: solid → H1 (normal hexagonal) → V1 (normal bicontinuous-type cubic) → Lα (lamellar) → liquid. FT-IR measurements for the mixture with this composition revealed the following features concerning the conformational structure of the C12E7 molecule and the interaction between the surfactant and D2O in each phase. In the solid phase, the polyoxyethylene (POE) chain of the surfactant molecule has a rather extended structure with ...